Abstract Book
www.biosensor2016.hacettepe.edu.tr
Biosensors 2016 3rd International Congress on Biosensors Biomaterials, Bioinformatics, Biosensors, Electrochemistry, Nanobiotechnology, Nanomaterials, Single-cell detection & analysis, Natural & synthetic receptors, MicroPADs, Microfluidic systems and more….
Hacettepe University, Mehmet Akif Ersoy Hall, Beytepe Campus
5-7 October 2016 Ankara, Turkey
Organized by
Hacettepe University Gazi University Bilkent University Dear Colleagues,
It was a great pleasure for us to see you in the 3rd International Congress on Biosensors. The congress was organized by Hacettepe University with the jointly contribution of Bilkent and Gazi Universities.
Located at the capital of Turkey, the congress attracted top scientists, decision and policy makers, high-tech companies, start-up companies, entrepreneurs, investors and students from all around the region.
This three day Conference provided access to the most up-to-date and authoritative knowledge from both commercial and academic worlds, sharing best practice in the field as well as learning about case studies of successfully integrated bio-sensing technologies. The meeting provided the opportunity to highlight recent developments and helped many to identify the emerging and future areas of growth in this exciting field.
We are so happy to have you welcomed to Ankara for 3rd International Congress on Biosensors.
Sincerely yours,
Assoc. Prof. Dr. Memed Duman
3rd International Congress on Biosensors 5-7 October 2016 Mehmet Akif Ersoy Hall
Honorary President
Prof. Dr. A. Haluk Özen, Hacettepe University Congress Chair
Assoc. Prof. Dr. Memed Duman, Hacettepe University Congress Co-Chair
Assoc. Prof. Dr. Çağlar Elbüken, Bilkent University
Assoc. Prof. Dr. Gökhan Demirel, Gazi University Organizing Committee
Gülgün Aylaz, Hacettepe University
Esma Sari, Hacettepe University
Meltem Okan, Hacettepe University
Selim Sülek, Hacettepe University
İpek Akyılmaz, Hacettepe University
Congress Topics
Bioinformatics
Biomaterials
Commercial biosensors, manufacturing and markets
Electrochemistry
Microfluidics/Lab-on-a-chip devices
Molecular biology
Nanobiotechnology
Nanomaterials and nanoanalytical systems
Natural and synthetic receptors
Next generation sequencing microRNA
Organism- and whole cell-based biosensors
Aptamer based biosensors
DNA microarray chips and sensors
Enzyme biosensors
Immunosensors
Neurosensor
Optical sensors
MicroPADs
Printed biosensors and organic electronics
Sensors to Monitor Food Quality and Safety
Single-cell detection and analysis
WEDNESDAY, OCTOBER 5, 2016, 3rd INTERNATIONAL CONGRESS ON BIOSENSORS
08:30-09:30 Registration Opening Talk 09:30-09:45 Memed Duman (Congress Chair), Hacettepe University Prof. Dr. A. Haluk Özen (Rector-Honorary President), Hacettepe University Session Chair: Dirk Mayer Plenary Speaker- Arben Merkoçi, Catalan Institute of Nanoscience and Nanotechnology 09:45-10:30 PS0101-“Nanomaterials-based sensors for diagnostics applications” Invited Speaker- Vural Gökmen, Hacettepe University 10:30-11:00 IS0101-“Machine Vision-Tool to Monitor Food Quality and Safety During Processing” 11:00-11:15 Coffee Break
Session Chair: Arben Merkoçi Invited Speaker- Suna Timur, Ege University 11:15-11:45 IS0102-“Integration of Biomolecules to Electrochemical and Optical Systems” Invited Speaker- Alper Kiraz, Koç University 11:45-12:15 IS0103-“Optofluidic Microresonators for Bio/Chemical Sensing Applications” Oral Presentation- Gökhan Bakan, Antalya International University 12:15-12:30 OP0101-“Pattern-Free, CMOS Compatible Infrared-Absorption-Spectroscopy Surfaces for Sensing Bio-Molecule Monolayers” Oral Presentation- Müslüm Kaan Arıcı, Middle East Technical University 12:30-12:45 OP0102-“Salmonella Detection via Silica Nanoparticle based Lateral Flow Test Platform” Oral Presentation- Nilgün Dükar, Ordu University 12:45-13:00 OP0103-“miRNA Sensing Self-Propelled Hybrid Micromotors” 13:00-14:30 Lunch Break
Session Chair: Mustafa Kemal Sezgintürk Invited Speaker- Canan Dağdeviren, Harvard University 14:30-15:00 IS0104-“An ‘Unusual’ Story: The Biology Meets Its Match “ Invited Speaker- Filiz Kuralay, Ordu University 15:00-15:30 IS0105-“Impact of Nanotechnology on Biomedical Sciences: Biosensing and Drug Delivery” Oral Presentation- Murat Serhatlıoğlu, Bilkent University 15:30-15:45 OP0104-“Fabrication and Characterization of Miniaturized Optical Flow Cytometry Design” Oral Presentation- Zeynep Çağlayan, Middle East Technical University 15:45-16:00 OP0105-“Dielectrophoretic Spectra of Polymorphonuclear White Blood Cells” 16:00-16:15 Coffee Break
Session Chair: Suna Timur Invited Speaker- Humphrey Yiu, Heriot Watt University 16:15-16:45 IS0106-“Surface Functionalization of Nanoparticles for Immunosensing of Biomolecules” Oral Presentation- Rükan Genç, Mersin University 16:45-17:00 OP0106-“Synthesis of Functionalized Fluorescent Carbon Nanoparticles as Artificial Enzymes and Signaling Tools for Their Use in Bioanalysis” Oral Presentation- Selmihan Şahin, Süleyman Demirel University 17:00-17:15 OP0107-“Preparation of Polypyrrole based Electrodes for Glucose 6-Phosphate Determination”
17:15-19:00 Poster Presentations Session 1 PP0101-PP0156
THURSDAY, OCTOBER 6, 2016, 3rd INTERNATIONAL CONGRESS ON BIOSENSORS
Session Chair: Haluk Külah Invited Speaker- Dirk Mayer, Forschungszentrum Jülich 09:00-09:30 IS0201-“Aptamer-based Biosensor with Electrochemical Current Rectification as Signal Amplification Strategy” Invited Speaker- Selim Ünlü, Boston University 09:30-10:00 IS0202-“Multiplexed Digital Detection of Protein Biomarkers for Cancer Diagnosis” Oral Presentation- Hilay Şencan, Boğaziçi University 10:00-10:15 OP0201-“Investigation of Protein Adsorption on Gradually Reduced Graphene Oxide Modified Surfaces by QCM” Oral Presentation- Erhan Zor, Necmettin Erbakan University 10:15-10:30 OP0202-“Paper-based Sensors as Optical Chiral Discrimination Platform” 10:45-11:00 Coffee Break
Session Chair: Selim Ünlü Invited Speaker- Haluk Külah, Middle East Technical University 11:00-11:30 IS0203-“BioMEMS and Microfluidic Devices for Lab-on-a-Chip Applications” Invited Speaker- Mustafa Kemal Sezgintürk, Namık Kemal University 11:30-12:00 IS0204-“ITO based Disposable Biosensors and New Immobilization Agents” Oral Presentation- Ziya Işıksaçan, Bilkent University 12:00-12:15 OP0204-“Point-of-Care Measurement of Erythrocyte Sedimentation Rate” Oral Presentation- Fatma Doğan, Eskişehir Osmangazi University 12:15-12:30 OP0205-“Nanopore-Integrated Microfluidic Biosensors with Single Molecule Detection Capability” Oral Presentation- Yeliz Yavuz Çelik 12:30-13:00 S0201- “Metrohm Autolab and DropSens News” 13:00-14:30 Lunch Break
Session Chair: Yıldız Uludağ Invited Speaker- Uğur Tamer, Gazi University 14:30-15:00 IS0205-“Rapid Detection Strategies for Pathogens Using Functionalized Nanoparticles” Oral Presentation- Murat Uygun, Adnan Menderes University 15:00-15:15 OP0206-“Biomimetic Carbon Dioxide Sequestration by Using Carbonic Anhydrase Attached Micromotors” Oral Presentation- Mustafa Yorulmaz, ASELSAN Research Center 15:15-15:30 OP0207-“Single-Particle Imaging for Biosensor Applications” Oral Presentation- Kutay İçöz, Abdullah Gül University 15:30-15:45 OP0208-“Cell Phone Microscopy + Image Processing: Low Cost Readout Method for BioMEMS” Oral Presentation- Sevde Altuntaş, TOBB Economics and Technology University 15:45-16:00 OP0209-“Detection of Alzheimer`s Protein on Polycarbonate Nanopillared Films by Using Surface Enhanced Raman Spectroscopy” 16:00-16:15 Coffee Break
Session Chair: Alper Kiraz Invited Speaker- Yıldız Uludağ, TÜBİTAK BİLGEM 16:15-16:45 IS0206- “MiSens Device as a New Automated Biosensing Platform based on Real-time Electrochemical Profiling (REP)” Oral Presentation- Eda Çelik, Hacettepe University 16:45-17:00 OP0210-“Glycophage based Array as an Alternative Biosensor for Pathogen Detection” Oral Presentation- Resul Sarıtaş, Siirt University 17:00-17:15 OP0211-“Detection of Micro and Nanoparticles in a Microfluidic Device Using Resistive Pulse Sensing Technique” 17:15-19:00 Poster Presentations Session 2 PP0201-PP0256 19:30 Gala Dinner
FRIDAY, OCTOBER 7, 2016, 3rd INTERNATIONAL CONGRESS ON BIOSENSORS
Session Chair: Filiz Kuralay Invited Speaker- Urartu Özgür Şafak Şeker, Bilkent University 09:00-9:30 IS0301- “Synthetic Genetic Circuits Operated Whole Cell Biosensors” 09:30-10:00 Invited Speaker- Adil Denizli, Hacettepe University Oral Presentation- Fatih Şen, Dumlupınar University 10:00-10:15 OP0301-“Next Generation Biosensors: Near-Infrared Fluorescent Single-Walled Carbon Nanotubes” Oral Presentation- Meltem Okan, Hacettepe University 10:15-10:30 OP0302-“Molecularly Imprinted Polymer based Microcantilever Sensor for the Selective Determination of Erythromycin in Water Resources” 10:30-10:45 Coffee Break
Session Chair: Urartu Özgür Şafak Şeker Invited Speaker- Ömür Çelikbıçak, Hacettepe University 10:45-11:15 IS0303-“Mass Spectrometry in Biomedical Research” Oral Presentation- Hasret Subak, Yüzüncü Yıl University 11:15-11:30 OP0303-“Electrochemical Detection of Interaction Between Plantago Anatolica and DNA by Using Disposable Biosensors” Oral Presentation- Mehmet Yılmaz, Sinop University 11:30-11:45 OP0304-“ Thin Films of p-type Organic Semiconductors as SERS Substrates” Oral Presentation- Gözde Aydoğdu Tığ, Ankara University 11:45-12:00 OP0305-“Simultaneous Electrochemical Determination of Ascorbic acid, Dopamine and Uric Acid based on Gold Nanoparticles-Graphene oxide-Poly-(2,6-Pyridinedicarboxlic Acid) Modified Electrode” Oral Presentation- Irmak Karaduman, Gazi University 12:00-12:15 OP0306-“Acetone Gas Sensor based on ZnO Nanostructure Produced by Successive Ionic Layer Adsorption and Reaction (SILAR) Method” Oral Presentation- Pınar Kara, Ege University 12:15-12:30 OP0307-“Biosensing Strategy for Detection of Bacterial Susceptibility Against Beta Lactamases” Oral Presentation- Dilber Ece Sezgin, Eskişehir Osmangazi University 12:30-12:45 OP0308-“RNA SELEX for Green Fluorescent Protein and Application of Selected Aptamer to Optic Biosensors” 12:45-14:30 Lunch Break
Session Chair: Ömür Çelikbıçak Invited Speaker- Arzum Erdem Gürsan, Ege University 14:30-15:00 IS0304-“Nanomaterials Integrated Electrochemical Biosensors” Oral Presentation- Günnur Güler- Ege University 15:00-15:15 OP0309-''Rapid Detection of Disease Biomarkers with ATR-FTIR Spectroscopy'' Oral Presentation- Derya Koyuncu Zeybek, Dumlupınar University 15:15-15:30 OP0310-“A Label-Free Electrochemical Immunosensor based on ERGO for Determination of Hemoglobin A1c” Oral Presentation- Gülgün Aylaz, Hacettepe University 15:30-15:45 OP0311-“A Novel Fiber based MALDI Probe for Selective Detection of Ciprofloxacin” Oral Presentation- Zeeshan Rashid, Koç University 15:45-16:00 OP0312-“Smart Surface based Guiding of Microdroplets Over Laser Ablated Sinusoidal Rail” Oral Presentation- Recep Üzek, Hacettepe University 16:00-16:15 OP0313-“ Functional GQDs Nanocomposite Fabricated for Direct and Rapid Detection of BPA with Paper Based Fluorescent System”
16:15-17:15 Closing and Award Ceremony
ABSTRACTS
Invited Speakers
Nanomaterials-based sensors for diagnosticsapplications
Arben Merkoçi1
1 CREA Research Professor & Group Leader Nanobioelectronics & Biosensors Group Catalan Institute of Nanoscience and Nanotechnology (ICN2) Campus de la UAB 08193 Bellaterra (Barcelona) Spain& CIN2 (ICN-CSIC) Barcelona, Catalonia, Spain
Machine Vision-Tool to Monitor Food Quality and Safety During Processing
Vural Gökmen1
1Food Engineering Department, Hacettepe University, Ankara, Turkey
Integration of Biomolecules to Electrochemical and Optical Systems
Suna Timur1
1Ege Üniversitesi, Fen Fakültesi, Biyokimya Bölümü, Bornova, İzmir, Turkey
Surface Functionalization of Nanoparticles for Immunosensing of Biomolecules
Humphrey Yiu1
1School of Engineering & Physical Sciences; Mechanical Process & Energy Engineering, Heriot-Watt University, Edinburgh, Scotland, UK
Aptamer-based Biosensor with Electrochemical Current Rectification as Signal Amplification Strategy
Dirk Mayer1
1Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich, Jülich, Germany
MiSens Device as a New Automated Biosensing Platform based on Real-time Electrochemical Profiling (REP)
Yıldız Uludağ1
1TÜBİTAK BİLGEM
Synthetic Genetic Circuits Operated Whole Cell Biosensors
Urartu Özgür Şafak Şeker1
1UNAM National Nanotechnology Research Center, Bilkent University, Ankara, Turkey
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Optofluidic Microresonators for Bio/Chemical Sensing Applications
Alper Kiraz1*
Departments of Physics and Electrical-Electronics Engineering
1Koç University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey
Abstract
Fluids possess unique properties for designing optical components and systems: (i) they have optically smooth interfaces and (ii) they provide a great flexibility in shape and refractive index. Optofluidics has recently emerged as an exciting new research field employing these unique properties of fluids to design optical components and systems that cannot be realized with classical solid-state materials. Optofluidic platforms usually exploit established design and manufacturing principles developed within the past two decades for the production of microfluidic chips. In this presentation, I will present some alternative approaches we have followed in my research group which can serve as inspirations for future optofluidic platforms.
Microdroplets of water and other polar liquids take almost spherical shapes when standing on a superhydrophobic surface. With their truncated microsphere geometry, they act as optical microcavities hosting whispering gallery modes. I will summarize the novel spectral tuning techniques, and organic/bio emitting device concepts, we developed using microdroplets that are standing on a superhydrophobic surface or trapped using different manipulation methods. I will discuss the recent experiments we have performed on optical spectroscopy of microdroplets using tapered optical fibers.
I will also discuss our results on hydrogen and humidity sensing using microdisk structures fabricated by SU-8 photoresist. The results that I will describe were partially supported by TÜBİTAK Grants No: 110T803, 112T972, and 115F446.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Nanomaterials Integrated Electrochemical Biosensors
Arzum Erdem1
1Ege University, Faculty of Pharmacy, Analytical Chemistry Department, 35100 Bornova, Izmir, Turkey
[email protected] [email protected]
Abstract
The nanoscale materials integrated sensors based on References nanoparticles, nanowires, dendrimers, nanotubes and other nanomaterials have recently received the 1. Palecek E., Bartosik M., (2012) Chem. Rev., considerable attention [1-6]. The development of 112; 3427. advanced biosensor platforms could impact significantly the areas of genomics, proteomics, 2. Gao W., Wang J., (2014) Nanoscale, 6; 10486. biomedical diagnostics and drug discovery. Electrochemical biosensors coupling the inherent 3. Patolsky F., Lieber C.M., (2004) Materials specifity of biorecognition reactions with high Today, 8; 20. sensitivity of physical transducers, present a great promise for sequence-specific nucleic acid 4. Sassolas A. , Leca-Bouvier B.D., Blum L.J., detection (DNA, RNA etc.) for clinical, (2008) Chem. Rev., 108; 109. environmental or forensic investigations [1-6]. 5. Ma W., Situ B., Lv, W. et al., (2016) Biosens An overview to nanomaterials integrated Bioelectron., 80; 344. electrochemical biosensors has been presented 6. Erdem A., (2007) Talanta, 74; 318. herein for monitoring of spesific biomolecular recognitions; such as, nucleic acid hybridization, aptamer-protein or drug-DNA interactions with their advantages and further applications.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
An ‘Unusual’ Story: The Biology Meets Its Match
Canan Dağdeviren1
1Koch Institute for Integrative Cancer Research, MIT, USA
Abstract In this talk, I describe novel materials, mechanics and device designs for emerging classes of wearable health Multifunctional sensing capability, ‘unusual’ formats monitoring systems and implantable, minimally with flexible/stretchable designs, lightweight invasive medical devices. These include a variety of construction and self-powered operation are desired electrodes, sensors, and energy harvesting components, attributes for electronics that directly interface with the with promising applications in bio-integrated human body. Today’s electronics are stiffer by up to six electronics, such as self-powered cardiac pacemakers, orders of magnitude compared to soft tissue. Thus, wearable blood pressure sensors, modulus sensor present systems limit intimate integration with biology. patches, and brain injectrodes. The devices can be I have focused on novel microfabrication techniques twisted, folded, stretched/flexed and wrapped onto and tricks to use active piezoelectric materials and curvilinear surfaces or implanted without damage or required electronic components, which have the shape significant alteration in operation. The fabrication and the mechanical properties that match with those of strategies and design concepts can be applied to various human tissues, in order to allow intimate integration biological substrates and geometries of interest, and thus without any irritation and/or harm on body. have the potential to broadly bridge the gap that exists between rigid, boxy electronics and soft, curvy biology.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Impact of Nanotechnology on Biomedical Sciences: Biosensing and Drug Delivery
Filiz Kuralay1
1Faculty of Art and Sciences, Ordu University, Ordu, Turkey
Abstract science for developing new detection methods and Nanoscale materials have drawn great attention in scientific investigations of the materials obtained. recent decades for the development of new Nanomaterials-based methods have various technologies. These materials including carbon commercial and technological applications with the nanotubes, graphene, nanoparticles, nanowires and advantage of eliminating the use of laborious, nanostructured polymers are widely used in expensive and complex methods. The aim of this biomedical, pharmaceutical, forensic, food safety, talk will be focusing on various nanomaterials- energy storage and environmental applications due based studies developed for the detection of nucleic to their excellent chemical, mechanical, electrical, acids and neurotransmitters and nano/ structural, optical and thermal properties. They microactuators for controlled drug release and constitute an emerging, interdisciplinary field of delivery.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
BioMEMS and Microfluidic Devices for Lab-on-a-Chip Applications
Haluk Külah1,2
1METU MEMS Center, Ankara, Turkey 2METU, Electrical and Electronics Engineering Department, Ankara, Turkey
Abstract examples for such applications include on-chip electrophoresis systems, polymerized-chainreaction (PCR) units, DNA This presentation introduces MEMS and microfluidics sequencing chips, and complex lab-on-a-chip devices [2-6]. technology for biomedical applications, including their These kinds of systems can be incorporated with wireless applications with examples from the literature. BioMEMS electronics technology and can be implanted inside the body related projects at METU-MEMS Center will be presented. for real time measurement of blood chemical values. Even Since the first introduction in 1970’s, MEMS technology is further, it is possible to form small reservoirs on the same chip becoming popular in many different application areas, for storing drugs and releasing them to the body according to including military, automotive, and consumer electronics, as it the analysis results. Similar systems can be used for diagnosis provides cheap, small, and smart sensors and actuators. This purpose. In this case, the technology is used to detect technology is especially critical for biomedical applications, predefined sort of cells, viruses, bacteria, proteins, or enzymes resulting in a new research area shortly called BioMEMS. in blood or in another liquid environment. This application is BioMEMS can be defined in general as “devices or systems very critical for prevention of diseases as well as early constructed using techniques inspired from microfabrication detection of them. Another interesting application for that are used for processing, delivery, manipulation, analysis, BioMEMS is smart bio-implants. Combining this technology or construction of biological and chemical entities [1].” with complex CMOS circuitry, it is possible to produce Application areas of BioMEMS range from diagnostics to biocompatible, small, smart and esthetic implants. There are micro-fluidics, systems for drug delivery, tissue engineering, currently various BioMEMS related projects going on at and implantable biomedical systems. One of the most METU-MEMS, including DNA electrophoresis systems [3], interesting application areas for this technology is the micro dielectrophoresis chips for cell seperation [4], gravimetric total analysis systems (Micro-TAS). Biological samples can sensors for cancer cell detection, microvalves and pumps for be analyzed in a very small area with considerably reduced lab-on-a-chip systems [5], and electrochemical sensors for cost and time, by forming micro-fluidic channels on silicon bacteria and toxin detection. Figure 1-3 show pictures of some substrate and combining them with onchip electronics. Some prototypes developed in our group.
Figure 1 Micro-channels and valves developed at METU-MEMS Figure 2 DEP-based cell separation chips
Figure 3 Microfluidic bacteria detection Figure 4 Parylene-based neural probes developed system and droplet-based drug effect at METU-MEMS analysis chips. system for rapid mutation detection via heteroduplex analysis," Electrophoresis J., Vol. 29, No. 18, pp. 3752-58, 2008. References [1] R. Bashir, “BioMEMS: state-of-the-art in detection, opportunities and [4] G. Yılmaz et. al. "A Dielectrophoretic Cell/Particle Separator prospects,” Advanced Drug Delivery Rev., Vol: 56, 11, 1565-86, 2004. Fabricated By Spiral Channels and Concentric Gold Electrodes,” TRANSDUCERS'07, pp. 73-76, June 2009. [2] V.M. Ugaz et. al. “Microfabricated electrophoresis systems for DNA sequencing and genotyping applications: current technology and future [5] E. Yıldırım et. al." An Electrostatic Parylene Microvalve for directions,” Philos Transact A Math Phys Eng Sci.; 362: 1105-1129, Controlling In-Plane Flow,” μTAS 2009, October 2009. 2004. [6] A.C.R. Grayson et. al., “A BioMEMS review: MEMS technology for [3] S. Sukas et. al., "A parylene based double-channel physiologically integrated devices,” Proceedings of the IEEE, Volume 92, microelectrophoresis Issue 1, pp. 6 – 21, Jan. 2004.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
ITO based Disposable Biosensors and New Immobilization Agents
Mustafa Kemal Sezgintürk1
1Namık Kemal University, Faculty of Arts and Science, Chemistry Department, Biochemistry Division, Tekirdağ, Turkey
1. Introduction conductivities, excellent substrate affinity, wide range electrochemical working area, stable The development biosensors has attracted a great electrochemical and physical properties and also deal of interest due to their high sensitivity and very low costs although i thas disposable properties. selectivity, and they are being increasingly used in many fields, such as analytical chemistry, industrial In this study, different biosensor systems based on process monitoring and control, clinical ITO substrates are reviewed. In these biosensing diagnostics, environmental monitoring and security, devices, new immobilization agents are used and food safety. Biosensors are also attractive for successively. Especially cancer biomarkers are pharmaceutical and biomedical analysis due to their prefered as the targets of these newly developed sensitivity (ng/mL or less) and high selectivity, and biosensor systems. sometimes their specificity, high benefit/cost ratio, simple use and rapidity of data collection [1]. Acknowledgement: This study was supported by
The Scientific and Technological Research Council The major advantages of biosensors over of Turkey (TUBİTAK) by the project number of traditional analytical methods, which will certainly 113 Z 678. lead in the near future to their even more pronounced use in the biomedical field, are: the fact that analyte detection can very often be made References without prior separation; the short response times that make possible the real-time monitoring of [1] Cristea C, Hârceagă V, Săndulescu R. biological and manufacturing processes; their ease Electrochemical sensor and biosensors. In: of use, allowing in-field or point-of-care Moretto LM, Kalcher K, editors. Environmental measurements; the flexibility and simplicity of Analysis by Electrochemical Sensors and preparation; the possibility of mass production and Biosensors. Vol. 1 Fundamentals. 1st ed. New low production costs; and the possibility of York: Springer; 2014. p. 155-165. miniaturization and automatization. [2]. [2] Morrison DWG, Dokmeci MR, Demirci U, Khademhosseini A. Clinical applications of As for the electrochemical transducer, important micro- and nanoscale biosensors. In: Gonsalves advances have been recently made thanks to the KE, Halberstadt CR, Laurencin CT, 22 introduction of new platforms for biosensor design, Biosensors - Micro and Nanoscale Applications such as nanotechnological materials and Nair LS, editors. Biomedical Nanostructures. nanostructured architectures (i.e., nanoparticles, 1st ed. New York: John Wiley & Sons Inc.; carbon nanotubes and nanofibres, graphenes, 2008. p. 1-10. nanostructured surfaces, etc.), which have improved [3] Farré M, Kantiani L, Pérez S, Barceló D. ( the sensitivity of the assembly [3]. 2009) Sensors and biosensors in support of EU di‐ rectives. TrAC Trends Anal. Chem. 2. Results and Discussion 28(2):170-185.
Materials used for the electrode and supporting substrate are usually conductive materials exhibiting low currents in an electrolyte solution, free of any electroactive species, over a relatively wide potential window.
Among the most frequently used materials for the electrode and supporting substrate is indium tin oxide, ITO) based materials. Recently the applications of indium tin oxide(ITO) film elec trodes have increased interest in biosensor fabrications owing to their high electrical
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Mass Spectrometry Applications in Biomedical Research
Ö. Çelikbıçak1
1Department of Chemistry, Hacettepe University, Ankara
Abstract References
Mass spectrometry's characteristics including [1] Hoffmann, Edmond De., and Vincent unequaled sensitivity and detection limits have Stroobant. Mass Spectrometry: Principles and raised it to an outstanding position among the other Applications. Chichester, West Sussex, analytical methods for diverse applications such as; England: J. Wiley, 2007. Print. atomic physics, reaction physics, reaction kinetics, [2] Hansell, Claire. “Enter the Matrix.” Nat Meth geochronology, all forms of chemical analysis (2015). doi:10.1038/nmeth.3527. (especially in biomedicine and ion-molecule [3] Setou, Mitsutoshi, and Hisao Oka. reactions) and determination of thermodynamic “Biomedical Mass Spectrometry.” Anal parameters [1]. By the early 1980s, mass Bioanal Chem (2011) 400: 1827. spectrometry was a well-established laboratory doi:10.1007/s00216-011-4944-0 technique for the characterization of small organic molecules. But larger molecules - particularly biological ones, including proteins, DNA and complex carbohydrates - were proving to be a challenge. Because mass analysis relies on the ionization and detection of species in the gas phase, the key problem was transferring sufficient energy to these large molecules to send them into the gas phase without destroying them [2]. Mass spectrometry has progressed extremely rapidly during the last three decades: production, separation and detection of ions, data acquisition, data reduction, etc. This has led to the development of entirely new instruments and applications. Today, intact analysis of the high molecular weight compounds (e.g. proteins, peptides, oligonucleotides, carbohydrates, synthetic polymers, large inorganic complexes etc.) are possible using soft ionization mass spectrometry techniques having high precision and accuracy. The most important soft ionization techniques of mass spectrometry are Electrospray Ionization Mass Spectrometry (ESI-MS) and Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) which are well-suited for macromolecular analysis. Additionally, complexes of these macromolecules, formed by weak noncovalent interactions, can be followed and complex stabilities, stoichiometries and interaction regions can be determined using the soft ionization mass spectrometry as well. More recently, after the genome era, proteomics and metabolomics are becoming more popular in the many fields of biology and medicine. In those “omics” approach, mass spectrometric techniques are not only useful but also nearly essential [3]. Nowadays, advances of mass spectrometry are serving the expectation of comprehensive coverage for those studies that focus on complex interactions within biological systems.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Multiplexed Digital Detection of Protein Biomarkers for Cancer Diagnosis
M. S. Ünlü1,2,3*, Fellow IEEE, F. Ekiz Kanik1, N. Lortlar Ünlü2,3, A. Usubütün4 and E. Ç. Seymour5 1 Electrical and Computer Engineering, Boston University, Boston, USA 2 Biomedical Engineering, Boston University, Boston, USA 3 Faculty of Medicine, Bahcesehir University, Istanbul, Turkey 4 Faculty of Medicine, Hacettepe University, Ankara, Turkey 5Aselsan, Ankara, Turkey
1.Introduction Due to the lack of molecular analysis devices, clinical diagnosis relied mostly on medical history and physical examination until about a hundred years ago. In modern medicine, in vitro tests are indispensable components of clinical practice with the sensitivity of standard immunoassays measuring protein biomarkers at picomolar concentrations. This level of sensitivity is sufficient for the diagnosis of infectious diseases when clear symptoms are present, however, it falls short for the detection of proteins that are important in cancer [1]. Perhaps one of the most exciting recent technological developments in biomarker analysis is single-molecule Figure 1 SP-IRIS detection platform. a) Optical setup counting or digital detection, an approach that provides which consist of LED lighting module, imaging objective resolution and sensitivity beyond the reach of ensemble and CCD imaging camera. b) Illustration of SP-IRIS measurements [2-4]. Digital detection not only provides sensor utilized for protein and nucleic acid detection. c) very high sensitivity, but also has the potential of making A sample image showing response from individual the most advanced disease diagnostic tools available at nanoparticles. low cost. We have developed a single molecule detection technology and we are exploring applications in highly sensitive diagnosis assays for cervical cancer. 3.Clinical Application We propose to apply the SP-IRIS platform to cervical 2.Interferometric Reflectance Imaging for Single cancer which is one of the most common and high Particle Detection mortality rate cancers among women worldwide due to The Interferometric Reflectance Imaging Sensor (IRIS) is its few early stage symptoms, poor diagnosis and a low-cost, compact and simple to use biosensing treatment possibility, and low survival rates. Early and platform developed at Boston University. IRIS has accurate detection of cervical cancer is important demonstrated high-throughput detection and especially in developing countries. We will translate quantification of protein-protein binding, DNA-protein emerging single-molecule counting or digital detection binding and DNA-DNA hybridization in real-time with methods to develop a highly sensitive multiplexed protein high sensitivity and reproducibility [5]. Recent significant assay. This technique will enable the detection of cervical advancements have allowed us to detect and identify cancer at an early stage while providing valuable individual captured nanoparticles [6]. This new modality information about the high-risk lesions at the first of IRIS is termed single-particle IRIS (SP-IRIS). SP-IRIS screening of the patient. shines light from an LED source on nanoparticles bound to the sensor surface, which consists of a silicon dioxide References layer on top of a silicon substrate (Figure 1a). [1] P.R. Srinivas, P.R. et al. “Trends in biomarker research for cancer detection,” Lancet Oncol. 2, 698–704, (2011) Interference of light reflected from the sensor surface is [2] M. Cretich, G. G. Daaboul, L. Sola, M. S. Ünlü, and M. Chiari "Digital detection modified by the presence of particles producing a distinct of biomarkers assisted by nanoparticles: application to diagnostics," Trends in Biotechnology, 33 (6), 343-351, (2015) signal that is captured by a conventional CCD camera. [3] A. Yurt, G. G. Daaboul, J. H. Connor, B. B. Goldberg, and M. S. Ünlü "Single Single molecule detection/counting is a disruptive nanoparticle detectors for biological applications," Nanoscale, Vol. 4, No. 3, pp. 715 – 726, (2012) technology and digital detection of proteins in microarray [4] D. Walt, “Optical methods for single molecule detection and analysis,” Anal. format is poised to become one of the most powerful Chem. 85, 1258–1263, (2013) [5] O. Avci, N. Lortlar Ünlü, A. Yalcin, and M. S. Ünlü, “Interferometric Reflectance tools in the field of biomarker detection because of its Imaging Sensor (IRIS)-A Platform Technology for Multiplexed Diagnostics and enormous potential in diagnostics. The SP-IRIS platform Digital Detection,” Sensors 15 (7), 17649-17665. (2015) [6] G. G. Daaboul, "High-Throughput Detection and Sizing of Individual Low-Index Nanoparticles and Viruses for Pathogen allows single molecule digital detection readout for Identification," Nano Letters, Vol. 10, No. 11, pp. 4727-4731 (2010). different targets on one chip/test with up to 1000 times [7] M. Monroe et al. “Single nanoparticle detection for multiplexed protein diagnostics with attomolar sensitivity in serum and unprocessed whole blood,” Anal Chem 85 (7), more sensitive (at atto-molar concentration) compared to 3698-3706 (2013). conventional fluorescence systems [7].
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Rapid detection strategies for pathogens using functionalized nanoparticles
Uğur Tamer1
1Department of Analytical Chemistry, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey
[email protected] Abstract (see Figure 1). In this work, we have synthesized The identification and the rapid detection of magnetic nanoparticles which are suitable for bacteria and viruses have been one of the most immunomagnetic separation of microorganism. The important issues for diagnostic, environment and surface of nanoparticles is modified with controlled food industry analysis. Many serious and even fatal orientation of antibodies. medical conditions result from bacterial or virus After immunomagnetic separation of bacteria from infection or contamination. Additionally it is matrix, labeled nanoparticles were immobilized to possible to have faults by erroneously negative the target bacteria on the surface of chip surface. tests. The created problems, however in term of Then, SERS measurement was performed on the public health or economic and industrial test line. SEM image of the test line of lateral flow development, suggest the development of immunoassay platform also indicated the alternative techniques of detection of these interaction of E.coli and gold particles with labeled microorganisms. Most accurate and reliable method antibody (Figure 2). of indicating the presence of bacteria is culture assay, but the conclusion of the culture assay require at least a period of 24 hours or more. It is very difficult to detect these bacteria in a short time which makes this subject very important all over the world. Therefore, rapid antigen tests (RAT) have been developed based on an antigen-antibody reaction. Particularly, fast, simple and inexpensive spot test applications based on the color change are used for qualitative analysis of bacteria. To get highly sensitive results in RAT test, it is necessary to increase the number of bacteria in broth media for at least 8 hours. However, the most important disadvantage of rapid antigen tests is low sensitivity and low accuracy for the detection of pathogens. Figure 1. Schematic diagram of the analytical Additionally it is possible to have faults by procedure erroneously negative tests. For quantitative analysis, highly sensitive and accurate detection methods are needed to reach a lower limit of detection limits, instead of the measuring color change. Although optical methods such as surface enhanced Raman Scattering (SERS) or fluorescence measurements have been used for pathogen detection, the construction of sensitive and reproducible substrate is still a challenge. Especially, the paper microfluidics or microchip- based measurement is a novel approach and will be a powerful alternative to the expensive Figure 2. SEM image of the test line after E.coli conventional techniques that necessitate the interaction consumption of excess amount of sample and materials. The present study aims to find out the The design, preparation and surface modification of most proper bioactive chip preparation method to immunoassay platform could be useable for the develop rapid, sensitive and selective biosensor for detection of of target bacteria from complex the quantitative determination of bacteria. This matrices. The optimization strategies and the presentation is mainly devoted to the tag based analytical performance of the chip-based assays immunoassay technique without the need for will be presented. multiple washing process and SERS or fluorescence labels will be placed in the system prior to analysis
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Oral
Presentations
Oral Presentation – OP0203
Biochar-Metalic Nanocomposite Based Glassy Carbon Paste Electrode Glucose Biosensors
Derya Bal Altuntaş1*, Gökçen Akgül2, Eduardo Moreno Jiménez3 and Elena Diaz 4
1 Department of Bioengineering, University of Recep Tayyip Erdogan University, Faculty of Engineering , 53100, Rize, Turkey 2 Department of Energy Systems Engineering, Recep Tayyip Erdogan University, Faculty of Engineering.. 53100, Rize, Turkey 3 Universidad Autonoma de Madrid, Department of Agricultural and Food Chemistry, Madrid, Spain 4 Universidad Autonoma de Madrid, Department of Chemical Engineering, Madrid, Spain
*Presenter: [email protected]
Abstract Biosensors are frequently used for the detection of components such as drugs, harmful pathogens, heavy metals or used for medical diagnoses by converting chemical and biological information together into easily detectable signals [1]–[5]. As reconstitution approach, a porous solid material as conductive support or transducer is developed and employed to the electrode surface. Novel researches on support materials integrated with biochar [6]–[9]. Biochar is a carbonaceous material, derived from Figure 2. EDS image of Mg-impregnated biochar biomass pyrolysis. For biosensor applications, some properties of biochar may be improved by some activations or modifications that would enhance biochar applicability. The surface area and average pore diameter of biochar can be developed by metal impregnation to excellent highly microporous structures. In this work, electro-analytical properties of metal impregnated-biochar was investigated as support material with biochar carbon paste electrode (BCPE). Biochar was derived from industrial tea waste (BCTW). Biochar from tea waste was Figure 3. EDS map of Mg-impregnated biochar impregnated with MgCl2 salt and calcinated. The structure contains MgO which dominates The electrochemical performances of The Mg- microporosity of biochar (Figure 1-3). BCPE was tested in glucose biosensor transducers. Acknowledgement: We are thankful to Universidad Autonoma de Madrid, Department of Agricultural and Food Chemistry and Chemical Engineering, Madrid, Spain for the opportunity to use their laboratory facilities. We gratefully acknowledge the financial support for chemical analyses provided by Recep Tayyip Erdoğan University, Scientific Research Projects Coordinator Unit (BAP) (Project No: RTEU-2014.29.109.04.01 and RTEU- 2015.53008.109.07.01). References Figure 1. Mg-impregnated biochar [1] R. Jain et al., Appl. Surf. Sci., 369, 151–158 (2016). The biochar has mostly micro-size particles alongside [2] M. Soler et al.., Biosens. Bioelectron. 66, 115–123 (2015). [3]H. Liu et al., Sensors Actuators, B Chem. 218, nano ones. This simply nano-sized biochar was used with 60–66 (2015). [4]X. Wang et al., Biosens. Bioelectron. glucose oxidase enzyme and in glassy carbon paste 81, 349–357 (2016). electrode (GCPE) as biosensor support material [5] S. Han et al., Biosens. Bioelectron. 80, 265–272 (2016). contributing to the sensitivity of glucose biosensors. [6] D. Agustini et al., Talanta 142, 221–227 (2015). [7] A. Gevaerd et al., Mater. Sci. Eng. C 62, 123–129 Among other sensing platforms, glucose biosensors are (2016). of special clinical and industrial significance because of [8] P. R. Oliveira et al., Food Chem. 171, 426–431 (2015). their role in monitoring blood-glucose levels in diabetes [9] T. M. Suguihiro et al, Bioresour. Technol. 143, 40–45 mellitus, one of the most prevalent metabolic disorders (2013). [10]A. A. Saei et al. Trends in Analy. Chem. 42, 216-227 (2013). worldwide. Similar to other sensing platforms, glucose biosensors have been the target to incorporate nanomaterials, including metal nanoparticles (MNPs) [10]. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0310
A label-free electrochemical immunosensor based on ERGO for determination of Hemoglobin A1c
Derya Koyuncu Zeybek1* and M. Özge Karaşallı1
1Department of Biochemistry, Faculty of Science and Arts, University of Dumlupınar, Kütahya, Turkey
*Presenter: [email protected]
Introduction GC/ERGO/HbA1cAb/BSA electrode). Finally, different concentrations of HbA1c antigen solutions Diabetes Mellitus (DM) is a group of metabolic prepared in PBS (pH 7.4) were added onto diseases characterized by hyperglycemia affecting GC/ERGO/HbA1cAb/BSA electrode and incubated about 150 million people around the world. For at 37°C (denoted as diagnosis and prevention of diabetes, measurement GC/ERGO/HbA1cAb/BSA/HbA1c electrode). of blood glucose value is the most commonly used
method. However, when blood glucose levels are 2.3. Electrochemical Measurement determined in this approach, which can fluctuate and Electrochemical behaviors of proposed electrodes reflect a glucose level can be affected by the daily were studied by CV and DPV in 10 mM pH 7.4 PBS diet and should be measured at regular intervals [1]. containing 5 mM Fe(CN) -3/Fe(CN) -4 and 0.1 M Hemoglobin A1c (HbA1c) or glycated hemoglobin 6 6 KCl. is defined as the gold standard in the diagnosis of HbA1c detection was performed via DPV in 10 mM DM [2] The level of HbA1c reflects the average pH 7.4 PBS containing 5 mM Fe(CN) -3/Fe(CN) -4 blood glucose levels over 2-3 months and is not 6 6 and 0.1 M KCl in the potential range from -0.1 to affected by daily fluctuations of glucose levels. -1 0.6 V with a scan rate of 0.05 V s . The change or Several methods have been reported for relative change in peak current of the redox couple determination of HbA1c, such as boronate-affinity was used to analyze the formation of antibody- chromatography, HPLC and capillary antigen complex. electrophoresis [3-5]. Besides, electrochemical immunosensors based on the specificity of antigen- 3. Results antibody interactions have been attracted increasing attention owing to their significant advantages such To characterize the fabrication process of the as simple procedure, high sensitivity, small immunosensor, CVs and DPVs were recorded at all analytical volumes, low cost, easy miniaturization, immobilization steps. According to the obtained and rapid detection [6]. results, the GC/ERGO/HbA1cAB/BSA electrode In this work, we reported a novel label-free can be used for label-free detection of HbA1c. electrochemical immunosensor capable of sensitive The antibody coating time and antibody-antigen detection of the DM biomarker HbA1c. The incubation time were optimized. The inferences immunosensor was fabricated based on effects of some biomolecules were evaluated. electrochemical reduced graphene oxide modified A linear relationship between DPV current change glassy carbon electrode. Quantitative determination and HbA1c concentration from 10 to 150 ng/mL of HbA1c was based on decreasing electrochemical (correlation coefficient of 0.9999) was obtained. -3 -4 signal for Fe(CN)6 /Fe(CN)6 redox couple. 4. Conclusions 2. Experimental In this study, we developed a novel label-free 2.1. Preparation of the GC/ERGO electrode electrochemical immunosensor for sensitive Graphene Oxide (GO) was prepared based on determination of HbA1c. modified Hummers method. 10 µl of GO (1mg/1mL ultrapure water) was dropped onto bare glassy 5. References carbon electrode surface, and then dried at room temperature. Subsequently, GO was [1] Pundir C.S., and Chawla S. 2014. Analytical Biochemistry 444, 47–56. electrochemically reduced in 0.1 M KCl by cyclic [2] Tanaka T., Kojiro I., Okochi M., Lim T-K.,Watanabe S., voltammetry. Harada M., and Matsunaga T. 2009. Analytica Chimica Acta 638 ,186–190. 2.2. Fabrication of the immunosensor [3] Tanaka T., Tsukube S., Izawa K., Okochi M.,Lim T- To immobilize anti-HbA1c antibody on GC/ERGO K.,Watanabe S.,Harada M.,ve Matsunaga T. 2007. Biosensors electrode, an adequate amount of anti-HbA1c and Bioelectronics 22, 2051–2056. [4] Little, Randie R., and Roberts, William L. 2009. Journal of antibody solution was dropped on the electrode Diabetes Science and Technology 3(3), 446-451. surface and incubated at 37°C (denoted as [5] Heli Siren , Laitinen P., Turpeinen U. and Karppinen P. 2002. GC/ERGO/HbA1cAb electrode). This procedure Journal of Chromatography 979, 201–207. was followed by incubation with BSA% to block [6] Danilowicz C. and Manrique J.M. 1999. Electrochemistry nonspecific binding sites (denoted as Communications 1(1), 22-25.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0308
RNA SELEX for Green Fluorescent Protein and Application of Selected Aptamer to Optic Biosensors
Dilber Ece Sezgin1* and Mehmet Mutlu2
1 Department of Biotechnology and Biosafety, Eskisehir Osmangazi University, 26480, Turkey 2 Department of Bioengineering, TOBB University of Economics and Technology, 06520, Turkey
*Presenter: [email protected]
Introduction via simple drop-coating. In order to confirm the avidin immobilization, surfaces were examined with FT-IR. There has been growing interest in identification and Poly-(A) tail addition to the 3’ end of the aptamer development of more specific and sensitive molecular molecules obtained by SELEX was envisaged would be recognition elements [1]. Aptamers have distinct ineffective on secondary structure and confirmed by M- advantages of over others including enzymes and Fold. 3’ biotinylated poly-(T) oligonucleotides antibodies as molecular recognition elements [2]. The immobilized on to avidin coated gold surfaces. Then distinguished molecular recognition properties of poly-(A) tail was added final selected aptamer pool artificially synthesized, short, single stranded DNA or immobilized with poly-(T) oligonucleotides on the RNA aptamers come from the in vitro selection strategy, surface. Thus, selected aptamer molecules immobilized which is, used combinatorial chemistry, called SELEX on to the gold surface via interaction between poly-(A) (Systematic Evolution of Ligands by EXponential and poly-(T) sequences. Aptamer target molecule enrichment) [3-5]. A typical SELEX procedure interaction on the gold surface has been shown by fundamentally consists of repetitive cycles of nucleic fluorescence microscopy. acid library preparation, selection, amplification and Results &Discussion isolation of ligand binding sequences [6]. At the end of the iterative cycles successful ligand binding sequences After 8 SELEX cycle final aptamer sequences analyzed are selected from chemically synthesized initial with DNA sequence analysis. Accordingly, it could be oligonucleotide library of about 1014 different sequences. easily seen that all sequences pass whole selection steps Despite the analytic potential of aptamer molecules they successfully. Unfortunately we could not be able to could not sufficiently come into use yet. This problem reduce the pool to one specific sequence because of the summarized as “thrombin problem” [7]. Potential of the limited number of SELEX cycles. We selected a number ability of construct any aptamer for any target limited by of better variant final sequences of previously described the focusing only a few aptamer especially thrombin sequence that binding GFP. We determined a novel; fast, aptamer usage. However thrombin aptamer, which is the reliable, easy and cheap affinity-SELEX method based first protein binding aptamer, selected as a therapeutic on known the strongest non-covalent avidin-biotin tool at first [8], it has become the major target in interaction that can be further used for any protein aptamer-based bioanalytic applications. Its use in mass molecule. Utilization of thiolated avidin molecules was sensitive bioanalytical sensing systems has brought some made the immobilization step easier. Additionally simple limitations with and there has been a growing need for poly-(A) poly-(T) interaction was made the any secondary confirmation about binding. immobilization step more reliable because secondary In this study, we investigate the applicability of GFP and structure of aptamers was not affected. Optical its aptamer as a model aptamer system for biosensor observations of interactions between selected aptamer applications with a higher reliability because it also will molecules and GFP were successfully demonstrated that provide an additional validation for the system with selected aptamer molecules and GFP could be used as a giving an optical signal besides the mass change signal. model system at biosensor research in terms of it permits Materials & Methods the dual control of immobilization. Here we report the first application of GFP aptamer system as a model Previously described, constructed and optimized RNA system for biosensor studies. aptamer library was used in this study. Selection steps of References SELEX cycles were carried out with an avidin-agarose matrix based affinity column. Target molecule GFP was [1] McKeague, M., et al., Int J Mol Sci 2010, 11, 4864-4881. biotinylated with a commercial kit (Sigma). In vitro [2] Balamurugan, S., et al., Analytical and bioanalytical chemistry 2008, 390, 1009-1021.D transcribed and purified RNA library was incubated with [3] Ellington, A.D.; Szostak, J.W., Nature 1990, 346, 818-822. GFP and binding sequences were separated, collected [4] Robertson, D.L.; Joyce, G.F. , Nature 1990, 344, 467-468 and purified with Sephadex-G25 column. Collected RNA [5] Tuerk, C.; Gold, L., Science 1990, 249, 505-510. molecules after each selection step were reverse [6] James, W., Encyclopedia of analytical chemistry 2000. [7] Baird, G.S., Am J Clin Pathol 2010, 134, 529-531. transcribed and subsequently PCR amplified. Thiolated [8] Bock, L.C., et al., Nature 1992, 564-566. avidin immobilization onto gold surfaces was carried out
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0210
Glycophage Based Array as an Alternative Biosensor for Pathogen Detection
E. Çelik1,2*
1Department of Chemical Engineering, Hacettepe University, Beytepe, 06800 Ankara, Turkey 2Institute of Science, Bioengineering Division, Hacettepe University, Beytepe, 06800 Ankara, Turkey
*Presenter: [email protected]
Introduction supernatant was obtained. When the phage preparations were analyzed by immunoblotting, a ladder of higher Printed carbohydrate microarrays (glycoarrays) have molecular weight bands were detected by the anti-Ec- emerged in the last decade as powerful, high-throughput OAg (O78) antiserum. The high-molecular-weight bands tools for screening glycan-protein interactions and have were absent in the samples obtained from cells that were been applied in areas such as disease detection, drug not infected with helper phage, lacked the phagemid, or discovery and host-pathogen interaction studies. lacked the O-antigen biosynthesis pathway as negative However, glycoarray applications are still limited by the controls, suggesting that O78 polysaccharide was expensive and complex methods available to synthesize covalently linked to MBP4xDQNAT-CT fusion protein glycans or by the challenges in identifying and isolating displayed on the phage particles. After optimized array glycans from natural sources. binding, probing and washing conditions, the signal-to- We have recently extended the power of phage display noise ratio was higher than 2.5. technique for the production and selective enrichment of phages that display N-linked glycoproteins [1] and Conclusion further engineered these so called “glycophages” for use in glycan microarray fabrication [2]. The advantages of glycophage-based arrays presented In this study, a simplified version of glycophage array here, include the low cost and scalability of phage/glycan was developed with phages displaying E. coli O78 O- production, which are biosynthetic processes involving antigen (a signature model molecule for a specific the cultivation of recombinant E. coli cells, and the ease pathogen), to study glycan binding proteins (GBPs) and with which glycophages can be recovered from the then optimized for specific phage production as well as culture supernatant without laborious purification steps. for array binding, probing and washing conditions. Furthermore, an array of O-antigens, which are the signature surface molecules of gram-negative bacteria, Experimental displayed on the phage particles provide the basis of a high-throughput technique for pathogen detection. Helper phage VCSM13 (Stratagene) was produced in E. coli TG1 and the glycophage particles were produced References in E. coli TG1ΔwaaL transformed with the phagemid pBAD-MBP4xDQNAT-CT::PglB and the plasmids [1] Çelik, E., Fisher, A.C., Guarino, C., Mansell, T.J., pMW07pglΔB or pMW07-O78, as described previously DeLisa, M.P. Protein Science., 19, (2010) 2006-2013. [2]. For array studies, high binding, half-area 96-well microtiter plates (Corning) were coated with 1-20x1011 [2] Çelik, E., Ollis, A.A., Lasanajak,Y., Fisher, A.C., glycophage particles and probed, blocked and washed Gur, G., Smith D.F., DeLisa, M.P. Biotechnology. using various strategies. The absorbance in each well Journal, 10, (2015) 199-209. was read at 492 nm after treatment with the o- Phenylenediamine dihydrochloride (OPD) substrate Acknowledgments- Marie Curie FP7 Career Integration (Sigma). Grant under REA grant agreement # 322096 and UNESCO-L’Oréal Young Women in Science Award. Results and Discussion Phage titers of ~2x1011 PFU per mL of culture
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0202
Paper-based Sensors as Optical Chiral Discrimination Platform
Erhan Zor1*, M. Esad Sağlam2 and Haluk Bingol3
1 Department of Science Education, Necmettin Erbakan University, Konya, Turkey 2 Institute of Science, Necmettin Erbakan University, Konya, Turkey 3 Department of Chemistry Education, Necmettin Erbakan University, Konya, Turkey
*Presenter: [email protected]
Introduction different papers such as common paper, filter paper, cellulose acetate membrane, cooking paper and Chirality, defined as the geometric property of a nanopaper (Figure 1) at various configurations including structure of being non-superimposable onto its mirror spots and signs (sensor) that are printed on papers using image, is a fundamental characteristic of life processes a filtration method or commercial inkjet printer (Figure [1]. The majority of bioactive materials and drugs are 2). It can be seen that color changes from red to violet in mainly composed of enantiomers of chiral molecules. the presence of only L-enantiomer for metallic For living systems, one enantiomer may influence nanoparticles and also photoluminescent quenching desirable property whereas the other may often displays effect is observed in the case of carbon quantum dot. a different biochemical activity or may cause serious side-effects [2]. Therefore, the development of simple and robust sensors for discriminative sensing of enantiomers of chiral substances is enormously important for drug discovery and pharmaceutical industry. Within this respect, paper-based (bio)sensing platforms which permit the performance of low-cost and fast response with good robustness have increased great attention for applications in diagnostics, environmental monitoring and food safety. Cost-efficient and eco- friendly green materials and large-scale processes are (1) (2) (3) attracting intensive research and commercial interests because they enable fabrication of a range of disposable Figure 2 Nanoparticles (NPs) embedded membrane (by devices for consumers [3]. filtration) for discrimination of D-/L-enantiomer (1). Ink-jet printed enantioselective carbon quantum dot signs (2) and spots (3) on transparent nanopaper.
Taking advantage of the inherent chirality of metallic NPs and chiral carbon/graphene quantum dots, we herein point out simple paper-based sensor platforms that can be used as a convenient colorimetric probe to discriminate enantiomers of chiral molecules, which can be a promising model and platform for discrimination of other biologically important enantiomers of chiral drugs and molecules. Figure 1. As-prepared wet nanopaper. Inset is SEM image of dried nanopaper. Acknowledgements: We express our deep thanks to the Scientific and Technological Research Council of With the recent advances in nanomaterials, great effort Turkey (TÜBİTAK) for financial support (215Z222). has been devoted to the development of miniaturized analytical platforms for paper-based optical sensing 4. References platforms [4]. However, paper-based platforms has been scarcely used for optical (bio)sensing applications and [7] Wattanakit et al., Nature Commun., 2014, 3325, 1-8. even no published study exists for optical chiral [8] Zor et al., Biosens.Bioelectron. 42, 2013, 321–325. discrimination explored by paper-based systems to date. [9] Huang et al., ACS Nano, 2013, 7 (3), 2106–2113. Hence, we sought to design, fabricate, and test simple, [10] Morales-Narvàez et al., ACS Nano, 2015, 9 (7), disposable and versatile chiral discrimination platforms 7296–7305. based on paper. Herein, we describe nanoparticle- embedded paper-based platforms that exhibit plasmonic or photoluminescent properties which can be used as optical chiral discrimination platform. We tested
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0301
Next Generation Biosensors: Near-Infrared Fluorescent Single-Walled Carbon Nanotubes
F. Sen1*
1 Sen Research Group, Department of Biochemistry, Dumlupinar University, Kütahya, Turkey
*Presenter: [email protected]
Abstract Single-walled carbon nanotube based biosensors are References particularly attractive for biomedical applications, because they exhibit a highly efficient fluorescent [1] Kim, J. H. et al. The rational design of nitric oxide signal in a near-infrared region where there is selectivity in single-walled carbon nanotube near- minimal interference from biological media. infrared fluorescence sensors for biological detection. Although single-walled carbon nanotubes have been Nature Chem. 1, 473–481 (2009). used as highly sensitive detectors for various compounds, their use as in vivo biomarkers requires [2] Zhang, J. Q. et al. Single molecule detection of nitric the simultaneous optimization of various oxide enabled by d(AT)15 DNA adsorbed to near parameters, including biocompatibility, molecular infrared fluorescent single-walled carbon nanotubes. J. recognition, high fluorescence quantum efficiency Am. Chem. Soc. 133, 567–581 (2011). and signal transduction. Adrressed herein, a new type of near infrared- fluorescent single-walled [3] Heller, D. A. et al. Optical detection of DNA carbon nanotubes sensors have been developed and conformational polymorphism on single-walled carbon polyethylene glycol ligated copolymer stabilizes nanotubes. Science 311, 508–511 (2006). their fluoresecent efficiency in solution, enabling intravenous injection into mice and the selective [4] Ahn, J. H. et al. Label-free, single protein detection detection of local nitric oxide concentration with a on a near-infrared fluorescent single-walled carbon very low detection limit. After localization within nanotube/protein microarray fabricated by cell-free the organelles, it is possible to follow the transient synthesis. Nano Lett. 11, 2743–2752 (2011). inflammation using nitric oxide as a marker and signalling molecule. Finally, we demonstrate that [5] Barone, P. W., Baik, S., Heller, D. A. & Strano, M. alginate-encapsulated single-walled carbon S. Near-infrared optical sensors based on single-walled nanotubes can function as implantable inflammation carbon nanotubes. Nature Mater. 4, 86–U16 (2005). sensors for nitric oxide detection. [6] Liu, Z. et al. Drug delivery with carbon nanotubes for in vivo cancer treatment. Cancer Res. 68, 6652– 6660 (2008). hν [7] Heller, D. A. et al. Multimodal optical sensing and e- analyte specificity using single-walled carbon nanotubes. Nature Nanotech. 4, 114–120 (2009). h+
Figure 1 DNA based carbon nanotube biosensor
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0205
Nanopore-integrated microfluidic biosensors with single molecule detection capability
F Dogan1,2,3*, F. Citak2, T. Albrecht3, J. B. Edel3 and M. Winterhalter2
1Nanoscience and Nanotechnology Section, Osmangazi University, Eskisehir, 26480, Turkey 2Faculty of Science and Engineering, Jacobs University, Bremen 28759, Germany 3Department of Chemistry, South Kensington Campus, Imperial College London, London, SW7 2AZ, UK
*Presenter: [email protected]
1. Introduction molecules may interact with the porin. As for solid-state nanopores, many non-porous Nanopores, both solid-state and biological ones, are semiconducting and insulating material (e.g. Si, SiO , excellent tools to detect single molecules with high 2 graphene, ploymers) can be employed for nanopore chip precision. They are being utilized in many applications fabrication. To date, there have been numerous reports so far including DNA-RNA sensing, epigenetics, DNA- over the material selection and the sensing ability of the protein interactions and even antibiotic resistance [1, 2]. solid-state nanopores. Next appears to increase its utility Detection using nanopores has numerous advantages by constituting an engineered device which can perform over conventional techniques (e.g. gel electrophoresis) multiple tasks within the capability of a single chip. and these are label-free detection, use of low sample 2. Devices and Detection Concept volumes and the ability to extract single molecule information. A nanopore can be either biological or Here, we present compact nanopore-integrated fabricated on a solid-state microchip. Biological microfluidic devices with single molecule detection nanopores exists naturally and can be experimentally capability. Both solid-state and biological nanopores inserted into artificially created lipid bilayers, allowing (single one of them) are integrated into a single the electrophysiological study of the ionic current microfluidic channel for the detection of single DNA across. The list for their utility can also be extended to molecules in flow and the investigation of antibiotic antibiotic research [3]; searching into a global problem permeability, respectively (Figure 1, Figure 2). faced today: Multi-drug resistance of Gram-negative bacteria.
Figure 2. Schematic of the device, a photography image and representative data for detection signal.
Figure 1. Schematic of biological nanopore-based The detection concept is simple: upon the application of biosensor-antibiotic permeability assay. the electric field, an ionic pathway is created from the channel to the back side of the device through a single Antibiotic research is important, because an unfortunate nanopore. As shown in Figure 2c, this is recorded as a end to the golden age of antibiotic era is approaching stable current trace due to the passage of the electrolyte and the world is in urgent need of new antibiotics, new ions. Once DNA is added to the channel, DNA blocks assays and new techniques to understand the resistance the pore for a certain amount of time and current and stop it if not too late. The problem clearly blockage events are observed, referring to individual intensifies from day to day. To address the issue, a DNA translocations. The shape of the events changes European Union initiative has recently been launched; depending on the charge, conformation and size of the ‘New Drugs for Bad Bugs’ (ND4BB)-Translocation molecule inside the pore. (www.translocation.eu) Project by Innovative 3. Conclusion Medicines Initiative (IMI) [4]. The project is devoted to In conclusion, these studies demonstrate that nanopore- understand the permeability of antibiotics to cross the integrated microfluidic sensors can be used for single cell wall of Gram-negative bacteria and to reach their molecule detection in flow, successfully. target. As a part of the Translocation project, we have 4. References developed an on-chip permeability assay characterizing single biological pores-porins that exist in the outer cell [1]. Miles BN et al. Chemical Society Reviews. 2012. wall of Gram-Negative bacteria and are responsible for [2]. Dekker C. Nat Nano. 2007;2(4):209-15. [3]. Nestorovich EM et al. PNAS. 2002;99(15):9789-94. the uptake of several hydrophilic molecules, nutrients [4]. Kostyanev T et al. The J. of An. Chem. 2016;71(2):290-5. and antibiotics- and addressing how single antibiotic
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0101
Pattern-free, CMOS compatible infrared-absorption-spectroscopy surfaces for sensing bio-molecule monolayers
G. Bakan1,2*, S. Ayas2, E. Ozgur2*, K. Celebi and A. Dâna2
1Department of Electrical and Electronics Engineering, Antalya International University, Antalya, Turkey 2UNAM, Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey
*Presenter: [email protected]
1.Introduction IR light (a) (b) Infrared (IR) vibrational spectroscopy is one of the 2 2 |E| /|Eo| widely used tools in chemistry and biology for 0 2 4 Monolayer 0 characterization of materials [1]. Absorption signatures -1 a-Si of materials due to molecular vibrations can be sensed -2 in the far-field signals (reflection or transmission (400 nm) (%) Signal spectrum) when a broadband infrared light source is Al 2 4 6 8 10 used. Current infrared measurement techniques such as λ (µm) Fourier Transform Infrared Spectroscopy (FTIR), however, require large amounts of molecules for Figure 1 (a) Illustration of the sensor surface with measureable absorption signals. Increasing the near- atop 5 nm PMMA layer as the probe material. field intensities in the vicinity of small amount of probe The enhancement factor at λ~5.77 µm as a molecules can result in similar absorption signals. This function of the vertical position is shown on top technique is known as Surface Enhanced Infrared of the illustration. (b) Simulated absorption Absorption Spectroscopy (SEIRA) and commonly uses signal of the PMMA layer. plasmonic surfaces for the field enhancement [2]. 2.2 Experiments Depending on the vibrational bands to be enhanced, the The surfaces are fabricated using both plasma- geometry of nano-patterns has to be tuned. Here, we enhanced-chemical-vapor-deposition and electron-beam demonstrate pattern-free surfaces which can consist of evaporation of a-Si on 80-nm-Al coated Si substrates. CMOS compatible materials such as Al and Si and For proof of concept experiments, the surfaces are provide large absorption signals when coated with coated with 5 nm PMMA layer, used as the probe monolayers of biological and chemical molecules [3]. material to test the sensing performance of the surfaces. The a-Si thickness is chosen to tune the surface’s first 2. Results order resonance to be close to the PMMA’s major vibrational band at 1732 cm-1 (λ~5.77 µm). The 2 Electric field intensity (|E| ) enhancement factor is measured signal intensities are ~6 % after background almost zero on the surface of a metal and increases up to subtraction. The sensing performance of the surface is 4 at a distance quarter wavelength (λ/4) away from the preserved up to extreme angles of incidence (75°) for surface when the metal is exposed to infrared light. both p- and s-polarizations. The surfaces are also Therefore, when a thin layer of probe material, such as a studied for other dielectric materials and tested with monolayer bovine serum albumin (BSA), is positioned other biological and chemical monolayers. quarter wavelength away from the surface, the absorption signal is expected to be enhanced by a factor 3. Conclusions of 4 compared to the absorption of a free-standing layer. We propose a pattern-free, CMOS compatible surface 2.1. Simulations structure for sensing monolayers of bio-molecules using The resonance wavelength, at which the electric field is infrared absorption spectroscopy. The surfaces can be enhanced to its maximum, is determined by the optical fabricated with low cost, on large area, and can provide properties of the dielectric material between the metal large absorption signals for very thin probe materials. and the probe material. The maximum enhancement Acknowledgements: This work is supported by factor of 4 can be achieved when air (n=1) is used as the TUBITAK grant #114E960 and EU FP7:People-IAPP dielectric material. However, leaving an air gap between NanoBacterPhageSERS. the metal and a thin layer of probe material complicates 4. References the fabrication process. Alternatively, IR-transparent materials can be used as the dielectric material for an [1] Kendall, C. et al., Analyst 134, 1029–45 (2009) easy fabrication at the expense of the enhancement [2] Adato, R. & Altug, H., Nat. Commun. 4, 2154 (2013). [3] Ayas, S. et al., ACS Photonics 3, 337 (2016). factor. For example, enhancement factors for some of the IR transparent materials are 3.95 for CaF2 (n=1.25), 3.7 for amorphous silicon (a-Si) (n=3.3) (Figure 1), and 3.6 for chalcogenides (Ge2Sb2Te5, n=3.6).
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0305
Simultaneous Electrochemical Determination of Ascorbic acid, Dopamine and Uric Acid Based on Gold Nanoparticles-Graphene oxide-Poly-(2,6- Pyridinedicarboxlic Acid) Modified Electrode
Gözde Aydoğdu Tığ*1, Gülendem Günendi1 and Şule Pekyardımcı1
1 Department of Chemistry, Faculty of Science, Ankara University
*Presenter: [email protected]
1. Introduction electrochemical determining of AA, DA and UA for the first time. The composite film was characterized by Ascorbic acid (AA), dopamine (DA) and uric acid (UA) scanning electron microscopy (SEM). Electrochemical play critical roles in human metabolism, central nervous behavior of GCE/AuNPs/P(PDCA)-GO was and renal systems. Abnormal concentration levels of investigated by using CV and EIS and compared with AA, DA and UA can cause serious health problems those of the bare GCE. Fig. 1 depicts the DPV response such as mental illness, cancer, Parkinson’s disease, of AA, DA and UA at bare GCE (a), GCE/P(PDCA) hyperuricaemia and gout [1, 2]. AA, DA and UA (b), GCE/AuNPs (c), GCE/AuNPs/P(PDCA) (d), coexist in human body fluids, thus simultaneous GCE/P(PDCA)-GO (e) and GCE/AuNPs/P(PDCA)-GO determination of these substances is important not only (f) electrodes. As shown in curve f, searching their physiological functions but also GCE/AuNPs/P(PDCA)-GO resolved the merged diagnosing diseases. However, the oxidation potentials voltammetric peak into three well-defined peaks. The of these compounds are too close to be separated at bare peak separations between AA and DA, AA and UA, DA electrodes for their overlapping signals. and UA were 161 mV, 336 mV and 175 mV, In this study, we propose a novel and simple strategy for respectively. Moreover, a remarkable increase in each simultaneous determination of AA, DA and UA based peak current was observed with comparison to the other on gold nanoparticles (AuNPs), graphene oxide (GO) modified electrodes. The effect of pH and pre- and poly(2,6-pyridinedicarboxlic acid) (P(PDCA)) concentration time were selected as 3.0 and 2.0 min, modified glassy carbon electrode (GCE).The modified respectively. Furthermore, the reproducibility, electrode shows excellent selectivity, sensitivity and repeatability, stability and applicability of the analysis reproducibility for the determination of AA, DA and in urine samples were also investigated. These results UA with lower detection limits. showed that the proposed method is a promising tool for 2. Materials and Methods simultaneous determination of AA, DA and UA in All electrochemical measurements were carried out by urine. using an AUTOLAB-PGSTAT 302N electrochemical analyzer connected with a three-electrode cell stand (Bioanalytical Systems, BAS, Inc., USA). A conventional three-electrode system consist of the bare or modified GCE as working electrode, a platinum wire as counter electrode, and Ag/AgCl (3 mol L−1 NaCl,) as reference electrode. The CVs and DPVs were analyzed by using NOVA 11.0 software (ECO Chemie). The AuNPs were electrodeposited on the surface of GCE −1 with 0.6 mmol L HAuCl4 solution in H2SO4 0.5 M for 15 cycles in the potential range of 0.2 to +1.2 V and a scan rate of 100 mVs–1 [3]. A freshly prepared monomer −1 solution containing 0.1 mol L−1 KCl and 1.0 mmol L−1 Figure 1 The DPVs responses of 100 µmol L AA, −1 −1 PDCA was prepared and then mixed with GO (1 mg/1 10 µmol L DA and 25 µmol L UA in 0.1 −1 mL) and sonicated for 1 h to form homogeneous mol L PBS (pH 3.0) at the bare GCE (curve mixture. The P(PDCA)-GO composite film was a) and modified electrodes (curve b-f) fabricated on the electrode surface by CV scanning of GCE/AuNPs in the above mixture solution from 0.0 V 4. References –1 to +2.0 V at a scan rate of 60 mVs for 10 cycles. [1] X. Niu, W. Yang, H. Guo, J. Ren, F. Yang, J. Gao, Talanta, 99 (2012) 984-988. 3. Result and Discussion [2] G. Zhang, P. He, W. Feng, S. Ding, J. Chen, L. Li, H. He, S. Zhang, F. Dong, Journal of Electroanalytical Chemistry, 760 In this study, GCE/AuNPs/P(PDCA)-GO was (2016) 24-31. constructed and this electrode was used for the [3] R.-S. Saberi, S. Shahrokhian, G. Marrazza, Electroanalysis, 25 (2013) 1373-1380.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0311
A Novel Fiber based MALDI Probe for Selective Detection of Ciprofloxacin G. Aylaz1*, A. Tevlek2, Ö. Çelikbıçak3 and M. Duman1 1 Nanotechnology and Nanomedicine Division, Hacettepe University 2 Department of Bioengineering, Hacettepe University 3 Department of Chemistry, Hacettepe University *Presenter: [email protected] Abstract As a result, signal/noise ratio (S/N) of CPX on PLLA Matrix-assisted Laser Desorption/Ionization Mass films in MALDI was higher than PLLA fibers. By the Spectrometry (MALDI-MS) has become a popular way, using MIP has risen the S/N ratio. DHB effect of the surface-based technique to analyze peptides, proteins and S/N ratio has not hold significant for detection CPX on many other molecules with biological origin. Large molar films and fibers in existence MIPs. excess of a matrix, which is usually a organic acid, is used for increasing the ultraviolet (UV) absorbing. In MALDI, the analyte is first co-crystallized with matrix compound, and then analyte-matrix mixture evaporates with laser. The matrix is an important point for absorbing the laser energy and transporting the analyte to the detector [1][2]. New generated fibers have been produced with electrospinning technique. Electrospun fibers have already been used in MALDI as substrates. Different polymer solutions travel by high electric field. When polymer solution is exposed to the electrical effect, solvent of the solution evaporates quickly and charged polymer is jet- transferred to the metal collector. The feed rate of polymer solution, the distance of solution input point and collector, the electric field range, solvent and polymer type are the important parameters for diameter of electrospun fibers [3]. Molecularly Imprinted Polymer (MIP) technology is a new approach for enrichment, selective detection studies and separation of molecules from undesired molecules. Monomer, initiator, cross linker and template molecule Figure 1.MALDI-MS Spectrums of CPX on MIP modified are mixed at optimum conditions for producing. After the electrospun PLLA fiber (a) and MIP modified electrospun polymerization proses, the template molecule is washed PLLA fiber with %2,5 DHB Matrix. away with desorption solution for creating template molecule imprinted polymer [4]. References [1] Harrison Alex G, “Chemical Inonization Mass In this study, Ciprofloxacin (CPX) which is antibiotic was Spectrometry”.CRC Press,2nd Edition,1992. imprinted. The films and electrospun fibers were [2] Hansell, Claire. “Enter the Matrix.” Nat Meth (2015). synthesized with Poly L Lactic Acid (PLLA) polymer and doi:10.1038/nmeth.3527. they were characterized by Fourier transform infrared [3] Md. Abdul Awal,” Development Of Continuous Bio-Composite spectroscopy (FTIR) and Scanning Electron Microscopy Fibres”, Doctor of Philosophy (SEM). Some type of films and fibers were produced with Faculty of Forestry, University of Toronto, 2012. 2,5-Dihydroxybenzoic acid (DHB) because to seek [4] Giuseppe Vasapollo, Roberta Del Sole, Lucia Mergola, Maria Rosaria Lazzoi, Anna Scardino, whether increasing of the ionization efficiency in Sonia Scorrano and Giuseppe Mele,”Molecularly Imprinted MALDI-MS or not. Polymers: Present and Future Prospective” International Journal of Molecular Sciences,2011,12,5908-5945.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0309
Rapid Detection of Disease Biomarkers with ATR- FTIR Spectroscopy
Günnur Güler1* and Ercüment Karasulu1
1Department of Biosimilar Drugs, Center for Drug R&D and Pharmacokinetic Applications, ARGEFAR, Ege University, Izmir, Turkey
*Presenter: [email protected]
1. Introduction samples. For instance, IR spectra provide fingerprint- Infrared (IR) spectroscopy is a molecular vibrational like signatures of nucleic acids originating from base, spectroscopy that yields information about the sugar and phosphate groups. Thus, the ATR-FTIR biochemical composition, bonding properties and technique as a high-sensitive optical biosensor can be a molecular structure (and environment) of biological potential alternative tool which paves the way for the macromolecules. It is a time-saving and non-destructive rapid, simple and label-free detection of disease technique which requires low setup and running cost. biomarkers in early clinical diagnosis and biomedical Therefore, it is frequently used for analyzing of tissue, research area. cell and body fluids which composed mainly of proteins, lipids, carbohydrates and nucleic acids (DNA, RNA and microRNA). Any changes in these biological macromolecules are considered to be biomarkers for diagnosis and monitoring of some human diseases (i.e., cancer); therefore, IR technique can be used for rapid, simple and label-free detection of disease biomarkers [1-4]. 2. Experimental The current talk deals with the theoretical and experimental aspects of attenuated total reflection- Fourier transform infrared (ATR-FTIR) spectroscopy for the study of synthetic nucleic acids (DNA, RNA and Figure 1: ATR-FTIR absorbance spectra of rat tissues microRNA), cell lines as well as tissues in the mid-IR (unpublished data). spectral region of 4000-700 cm-1. Measurements of the samples were performed with a IRTracer-100 FTIR 4. References spectrometer (Shimadzu, Japan) combined with an ATR [1] Güler, G., Gärtner, R.M., Ziegler, C. and Mäntele, accessory and equipped with a DLATGS detector. A M. (2016). “Lipid-Protein Interactions in the Regulated total of 128 scans were averaged for each interferogram Betaine Symporter BetP Probed by Infrared at 4 cm-1 resolution. Spectroscopy.” The Journal of Biological Chemistry 291(9): 4295–4307. 3. Results FTIR enables to follow the proteomic, lipidemic and [2] Kaplan, M., Kılıc, T., Guler, G., Jihane, M., Amine, metabolic changes in real samples (i.e., cell, tissue, A., Ozsoz, M. “A novel method for sensitive microRNA body fluids) induced by diseases or drug treatment. On detection: electro polymerization based doping.” the basis of the FTIR data of rat tissues (Fig. 1), a peak Biosensors and Bioelectronics, in Press, accepted of the protein amide I band can be seen around 1650 manuscript, cm-1 and the amide II band appears around 1550 cm-1. http://dx.doi.org/10.1016/j.bios.2016.09.050. Lipid CH2 and CH3 signals appear between 2800 and [3] Movasaghi, Z., Rehman, S. and Rehman,I. (2008). 3000 cm-1 region while lipid ester carbonly groups are -1 “Fourier Transform Infrared (FTIR) Spectroscopy of detected around 1740 cm . Nucleic acid signals arising Biological Tissues.” Applied Spectroscopy Reviews from base, sugar and phosphate molecules are detected 43(2): 134–79. in the 1800-800 cm-1 region. Therefore, this technique can be used for deciphering of disease biomarkers. [4] Banyay, M., Sarkar, M. and Gräslund, A. (2003). “A Library of IR Bands of Nucleic Acids in Solution.” ATR-FTIR is a well-established tool for fast, label-free Biophysical Chemistry 104(2): 477–88. and cost-effective detection of biomolecular targets (i.e. nucleic acids) and requires a small amount of sample (a few µl) without particular sample preparation. With tracking of IR spectral changes, it is possible to observe alterations in the molecular structure as well as expression level of biological macromolecules in real
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0303
Electrochemical Detection of Interaction between Plantago Anatolica and DNA by Using Disposable Biosensors
Hasret Subak1,2*, Abdullah Dalar3 and Dilsat Ozkan-Ariksoysal1*
1*Ege University, Faculty of Pharmacy, Analytical Chemistry Department, Izmir, Turkey 2Yuzuncu Yil University, Faculty of Pharmacy, Analytical Chemistry Department, Van, Turkey 3Yuzuncu Yil University, Faculty of Pharmacy, Pharmaceutical Botany Department, Van, Turkey
*Presenter: [email protected]
Introduction References Plantago anatolica is an endemical and ethnomedical traditional folk medicine used in eastern anatolia for analgesic purposes. In this study, the plant extract (as [1] Ozkan-, D. Karadeniz-,H. Erdem, A. Mascini,M. lyophylisated powder) was prepared in different Ozsoz, M. Journal of Pharmaceutical and Biomedical solvents such as n-hekzan, acetone, ethanol, methanol or Analysis 35 (2004) 905. pure water. There has still been groving interest in studying the [2] E. Palecek, M. Bartosik, Chemical Reviews. (2012), recognition and quantification of the compound-DNA 112, 3427. interactions by using electrochemical biosensors because they give good information about the [3] D. Ozkan-Ariksoysal, B. Tezcanli, B. Kosova, M. interaction mechanism of the drug and DNA with their Ozsoz, Anal. Chem. (2008) 80, 588. fast, simple and cost-effective methodologies. In this study, the electrochemical behavior of the plant [4] Ceren Sengiz, Gulsah Congur, Ece Eksin, Arzum extract was monitored and the effect of this extract on Erdem, Electroanalysis 2015,27, 1855 –1863. DNA was investigated by using biosensor technology. The interaction mechanism of the extract was also [5] F. Lucarelli, G. Marrazza, A. P. F. Turner, M. studied and evaluated with bare or nanomaterial Mascini, Biosensors & Bioelectronics. (2004), 19, 515. modified disposable carbon electrodes by using differential pulse voltammetry (DPV). Thus, the optimal [6] Y.U. Kayran, D.Ozkan-Ariksoysal, B.Tezcanli, B. experimental parameters were determined and obtained Kosova, Mehmet Ozsoz, Electroanalysis (2013), 25, 12, results showed that newly-developed biosensor could be 2668. used for the rapid, cost effective and sensitive detection of plant extract–DNA interaction.
Figure 1 Schematic illustration of the electrochemical sensor for the detection of Plantago anatolica and DNA interaction.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0242
Electrochemical Impedimetric Immunosensor Based on Gold Nanoparticles Functionalized Screen-Printed Gold Electrode for Carcinoembryogenic Antigen (CEA) Tumor Marker Detection
Ş. Sultan1*, Ç. K. Rabia1 and K. Merve2
1 Department of Bioengineering, Yıldız Technical University, İstanbul, Turkey 2 Department of Medical Biology, Süleyman Demirel University, Isparta, Turkey
*Presenter: [email protected]
Abstract References
Impedimetric immunosensors are constructed with [1] M.I. Prodromidis, Impedimetric immunosensors-A antibody immobilization of working electrode and their review, Electrochimica Acta, 55 (2010) 4227-4233. working principle is that occuring a correlation between [2] M. Taheri, U. Saragovi, A. Fuks, J. Makkerh, J. antigen concentration and obtained resistance after an Mort, C.P. Stanners, Self recognition in the Ig electrochemical Ab-Ag interaction. EIS is generally superfamily - Identification of precise subdomains in used to characterize these type detections in biosensor carcinoembryonic antigen required for intercellular applications [1]. Electrochemical impedimetric adhesion, Journal of Biological Chemistry, 275 (2000) biosensors have significant advantages for sensitive 26935-26943. detection of cancer biomarkers which are being smaller, [3] X.L. Li, R. Yuan, Y.Q. Chai, L.Y. Zhang, Y. Zhuo, Y. faster, more sensitive, cheaper devices, without Zhang, Amperometric immunosensor based on toluidine radiation hazards, allowing label-free, concurrent blue/nano-Au through electrostatic interaction for detection, simple production, less time consuming, rapid determination of carcinoembryonic antigen, Journal of detection, having longer shelf life, and not complicated Biotechnology, 123 (2006) 356-366. procedure. These properties will substantially get easier [4] J. Wu, J. Tang, Z. Dai, F. Yan, H. Ju, N. El Murr, A early dianostic of cancer at beginning phases. disposable electrochemical immunosensor for flow Carcinoembryogenic antigens which are cell surface injection immunoassay of carcinoembryonic antigen, glycoproteins [2] are used as an important biomarker in Biosensors & Bioelectronics, 22 (2006) 102-108. human serum associated with colorectal, lung, breast [5] J. Wang, Electrochemical biosensors: Towards point- cancer and ovarian carcinoma [3, 4]. CEA of-care cancer diagnostics, Biosensors & Bioelectronics, quantification analysis with electrochemical impedance 21 (2006) 1887-1892. spectroscopy promotes early diagnosis of cancer which [6] S.Y. Xu, X.Z. Han, A novel method to construct a is crucial for the successful treatment of the disease and third-generation biosensor: self-assembling gold increases health standards of people[5]. The gold layer nanoparticles on thiol-functionalized poly(styrene-co- has various advantages during immobilization process acrylic acid) nanospheres, Biosensors & Bioelectronics, thereby the easy adsorption of biomaterials relates to 19 (2004) 1117-1120. hydrophobic and thiol–gold interactions. In recent years, [7] D. Hernandez-Santos, M.B. Gonzalez-Garcia, A.C. gold nanoparticles (AuNPs) are commonly used to Garcia, Metal-nanoparticles based electroanalysis, enhance more sensitive electrochemical immunoassay Electroanalysis, 14 (2002) 1225-1235. for immobilization of antibody. AuNPs provide strongly [8] J.M. Pingarron, P. Yanez-Sedeno, A. Gonzalez- adsorbtion of antibody on working electrode during Cortes, Gold nanoparticle-based electrochemical immobilization due to its large specific surface area, biosensors, Electrochimica Acta, 53 (2008) 5848-5866. good biocompatibility, surface free energy of nanosized particles [6, 7]. AuNPs facilitate electron transfer between redox proteins and electrode surfaces, provide effective mass transport in electrochemical biosensor applications as making closer redox protein (monoclonal CEA antibody) to the electrode via nanosized structure. In the other words, AuNPs is a desirable intermediator for immobilization of antibodies [8]. In this study, the gold electrode is modified with thiol and AuNPs to develop an impedimetric biosensor to detect CEA as an important cancer biomarker.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0306
Acetone gas sensor based on ZnO nanostructure produced by Successive ionic layer adsorption and reaction (SILAR) method
Irmak Karaduman1*, Tuğba Çorlu1, Memet Ali Yıldırım2, Aytunç Ateş3 and Selim Acar1
1 Department of Physics, Science Faculty, Gazi University, Ankara, Turkey 2Department of Electric Electronics Engineering, Engineering Faculty, Erzincan University, Erzincan, Turkey 3Department of Material Engineering, Engineering and Natural Sciences Faculty, Yıldırım Beyazıt University, Ankara, Turkey
*Presenter: [email protected]
Abstract In this study, ZnO nanostructure is grown by With the rapid development of industrialization and Successive ionic layer adsorption and reaction urbanization in the past few decades, environment (SILAR) method and investigated its acetone gas pollution caused by the volatilization of hazardous sensing properties. The acetone sensing properties of gases has become an important issue. Acetone, as a the ZnO nanostructure was measured at different widely used solvent in industry and laboratory, can operating temperatures and depending on different volatilize easily and affect human health when its concentrations. Gas sensing measurements showed concentration is higher than 173 ppm [1]. Although the good acetone sensing performance of such the study on acetone sensor is necessary, the present sample at low operating temperature. The sample reported acetone sensors have suffered from some showed a fast response and recovery times, disadvantages, such as poor selectivity, inadequate excellent repeatability, and great potential for sensitivity [2]. Therefore, it is highly desirable to practical applications. develop high performance sensors for rapidly selective detection of acetone [3].
Among various metal oxide semiconductor (MOS)- based gas sensing materials studied so far, ZnO, as a nontoxic, inexpensive and wide-band-gap II-VI compound semiconductor, has been proved to be one of the promising materials for gas sensors [4]. It's well known that the properties of ZnO depend highly on its nanostructures, including crystal size, orientation and morphology. As a consequence, ZnO nanocrystals with highly controlled microstructures have been investigated extensively in recent years.
Figure 1 XRD pattern of ZnO nanostructure The traditional gas sensors using semiconductor produced by SILAR method oxides detect an objective gas in air from a change in current caused by the adsorption and/or References reaction of gases. When the sensors are exposed to [1] L.F. da Silva , A. C. Catto , W. Avansi Jr. , L. S. air, oxygen molecules adsorbed on the surface Cavalcante ,V. R. Mastelaro , J. Andres , K. would be ionized to O2−, O−or O2− by capturing free Aguir , E. Longo, Journal of Alloys and electrons from the conduction band which causes a Compounds 683, (2016) 186-190 [2] D. Chen, L. Ge, L. Yin, H. Shi, D. Yang, J. Yang, Sens. depletion layer and a potential barrier to charge Actuators B Chem. 205 (2014) 391-400 transport is developed. The possible reactions are [3] A.M. Diskin, P. Spanel, D. Smith, Physiol. Meas. 24 expressed as follows [4]; (2003) 107–119. − − 푂2(푔푎푠) + 2푒 → 푂 (1) [4] P. P. Sahay, Journal Of Materials Science 40 (푎푑푠) (2005) 4383 – 4385 The acetone gas sensing mechanism of sensing [5] W. Ping, T. Yi, H.B. Xie, F.R. Shen, Biosens. surface can be explained by Bioelectron. 12 (1997) 1031–1036. [5]: − − Acknowledgements: This work was supported by the 퐶퐻3퐶푂퐶퐻3(푔푎푠) + 8푂 → 3퐶푂2(푔) + 3퐻20 + 8푒 (2) TUBITAK (Grant 115M658) and Gazi University
Scientific Research Fund under Project No:05/2015-09.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0208
Cell Phone Microscopy + Image Processing: Low Cost Readout Method for BioMEMS
Kutay İçöz1*
1 Department of Electrical and Electronics Engineering, Abdullah Gül University, Kayseri, Turkey
*Presenter: [email protected]
1. Introduction 3. Cell Phone Microscopy According to data from World Bank approximately 7 Low cost spherical lenses are integrated with cell billion cell phones are being used worldwide. phones to develop portable microscopes [4]. These Advancements in micro fabrication technology enable systems can provide a resolution on the order of 1 to integrating various sensors in cell phones. Technical 10 μm. The cost of a single spherical ball lens is features and extensiveness make cell phones a tool for less than 10 cents. 100X magnification can be telemedicine. reached using a ball lens of 3.5 mm in diameter. Micro cantilevers are used to detect and measure In this work we discuss using cell phone microscopy proteins, cells and DNA using two operation modes: + image processing as a new readout method for resonant mode and static mode. Common techniques of cantilevers not replacing the existing ones but a signal readout from cantilevers are measurement of complementary low-cost, fast and portable changes in laser intensity, position, or piezoresistance alternative (Figure 1). Existing measurement (Table 1). methods for cantilevers provide detection of single In this study we investigate cell phone microscopy and bacteria and virus or cell measurements such as image processing as an alternative readout method for weighing. Cell phone microscopy can’t reach to micro cantilevers. This approach has limitations sensitivities for detecting viruses and can’t provide compared to conventional sensitive methods but weighing for any cell type however its current provides low cost, fast and mobile measurements and capability is sensitive enough for detecting most of can be considered as a first step analysis for micro the cell types and can be improved for bacteria. cantilevers. Image processing can also provide shape and size information of each cell. 2. Cantilevers Micro/nano cantilevers, are mostly fabricated from silicon, silicon oxide and silicon nitride, have been designed and used as label-free biomolecular detectors. Cantilever transducers convert biological signals into mechanical deflections that can be detected using optical, electrical and magnetic methods [1]. Figure 1 Left: Microcantilever imaged by optical light microscope, Middle: Spherical Ball Lens Table 1 Comparison of cantilever signal readout attached to cellphone Right: Microcantilever techniques imaged by the cellphone. Scale bar 100 μm.
Sensor Meas Resolut 4. References Type ured ion Quan [1] S. K. Vashist, “A Review of Microcantilevers for Sensing tity Applications A Review of Microcantilevers for Sensing Sandeep Kumar Vashist,” J. Nanotechnol. Online, pp. 1–16, Laser 0.01 Å Interfero 2007. Intens metry [2] K. S. Hwang, S.-M. Lee, S. K. Kim, J. H. Lee, and T. S. ity Kim, “Micro- and nanocantilever devices and systems for Laser 0.1 Å biomolecule detection.,” Annu. Rev. Anal. Chem. (Palo Alto. Optical Positi Calif)., vol. 2, pp. 77–98, 2009. Lever on [3] H. Etayash, K. Jiang, S. Azmi, T. Thundat, and K. Kaur, Piezoresis Resist 0.1 Å “Real-time Detection of Breast Cancer Cells Using Peptide- tive ance functionalized Microcantilever Arrays,” Sci. Rep., no. August, pp. 1–13, 2015. [4] Z. J. Smith, K. Chu, A. R. Espenson, M. Rahimzadeh, A. Numerous biosensor systems based on surface Gryshuk, M. Molinaro, D. M. Dwyre, S. Lane, D. functionalized cantilevers have been implemented for Matthews, and S. Wachsmann-Hogiu, “Cell-phone-based platform for biomedical device development and education detection of various biological targets such as bacteria, applications,” PLoS One, vol. 6, no. 3, 2011. virus, proteins, DNA/RNA and cells [2], [3].
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0304
Thin Films of p-type Organic Semiconductors as SERS Substrates
Mehmet Yilmaz1,2, Dilek Ozden1, Hakan Usta3 and Gokhan Demirel1*
1Bio-inspired Materials Research Laboratory (BIMREL) Department of Chemistry, Gazi University, Ankara, Turkey 2Department of Bioengineering, Sinop University, Sinop, Turkey 3Department of Materials Science and Nanotechnology Engineering, Abdullah Gül University, Kayseri, Turkey
*Presenter: [email protected] 1. Introduction signal intensities relative to that of the smooth gold film Since its discovery in 1974, surface-enhanced Raman as a result of the tip-focusing, cavity resonances and spectroscopy (SERS) has arisen as a powerful and antenna effects. Interestingly, although C8-BTBT thin- sensitive vibrational spectroscopic method providing the films deposited at α = 10o does not show any obvious 3D detection of various molecules at ultra-low morphology, a dramatic enhancement in the SERS signal concentrations. Numerous studies have been performed to is also observed, possibly due fabricate novel SERS platforms for different applications to formation of charge transfer covering chemistry, physics, medicine, and biology. mechanisms. Despite of attempts in this research field, the present SERS platforms still have some drawbacks such as stability and reproducibility limiting their practical applications. Small organic semiconductors, with their facile film deposition on flexible plastic substrates and compatibility with low-cost and large-area manufacturing/direct-write printing technique, exhibit exceptional charge transport/light manipulation properties and excellent contact formation with metals such as Au and Ag in various optoelectronic devices. In this study, to employ the advantages of these materials as SERS Figure 1 Top-view and cross-sectional SEM images of platform, thin layer of p-type organic semiconductor (2,7- C8-BTBT films fabricated by vapor deposition at a,b) α = dioctyl[1]benzothieno[3,2-b]-[1]benzothiophene,C8 90° and vapor deposition c,d) at α = 10° [1]. BTBT) was deposited through oblique angle physical vapor deposition (PVD) technique. The resultant organic Figure 2 SERS spectra of MB on Au-coated C8-BTBT thin film with conformal thin layer of gold (32 nm) films fabricated at a) α = 90° and b) α = 10°, and of c) a exhibited remarkable SERS performances in terms of smooth gold film on silicon [1]. enhancement (≈108), stability (>90 days), and reproducibility (RSD < 0.14). Two feasible routes for charge transfer may occur upon laser excitation, which are either from C8-BTBT/gold 2. Results and Discussion substrate to adsorbed MB molecule or from MB molecule to C8 BTBT/gold substrate. As shown in Figure 3, the SEM images (Figure 1) depict that the film morphologies highest occupied molecular orbital (HOMO) and lowest depend on dramatically the deposition method and the unoccupied molecular orbital (LUMO) energy levels of o deposition angle, α. For vapor-deposition at α = 10 2D C8-BTBT molecule, the work function of the gold as well microstructures with highly interconnected plate-like as the HOMO and LUMO energy levels of MB exhibit o grains are observed (Figure 1 c,d). For the case of 90 proper characteristics to create charge transfer complexes deposition angle, high density arrays of vertically aligned and the resultant SERS effect. ribbon-like micro-/nanostructures, which are highly favorable for SERS applications, were detected (Figure 1 a,b) as a result of π–π stacking interactions between the planar benzothieno[3,2-b]-[1]benzothiophene aromatic cores and van der Waals interactions between lipophilic alkyl chains at the molecular termini and also variations in film-growth mechanisms due to different deposition Figure 3 Schematic representations for possible thermodynamics/kinetics and shadowing effects. charge- SERS activity of these films was evaluated by using transfer mechanisms (a and b) between MB and the methylene blue (MB) as the Raman reporter molecule Au/C8-BTBT film [1]. (Figure 2). Due to its 3D ribbon-like micro- /nanostructures, gold-coated C8-BTBT films fabricated at References α = 90o exhibit a remarkable increment of the SERS [1] Yilmaz et al. Adv. Funct. Mater. 2015, 25, 5669– 5676.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0102
Salmonella Detection via Silica Nanoparticle based Lateral Flow Test Platform Müslüm Kaan Arıcı1*, Onur Bulut1,2, Oya Akça3, Meral Yücel1 and Hüseyin Avni Öktem1,2,4
1Department of Biological Sciences, Middle East Technical University, Ankara, Turkey 2 Faculty of Agriculture and Natural Sciences, Konya Food & Agriculture University, Konya, Turkey 3 Department of Molecular Biology and Genetics, Harran University, Şanlıurfa, Turkey 4 Nanobiz NanoBioTechnological Systems R&D Limited, Ankara, Turkey
*Presenter: [email protected]
1. Introduction target amplicon is applied to the sample pad, it Target-responsive nanodevices and nanostructures migrates along the strip and reaches the based on mesoporous silica nanoparticles (MSN) have oligonucleotide capped MSNs. Pore opening occurs been used for different purposes such as controlled drug by a displacement reaction in the presence of a delivery, diagnostic, sensing, and biomedical imaging. target complementary strand. This results in Unique features of MSNs provide advantages including hybridization of the two oligonucleotides, the large surface area, controllable particle and pore size, and uncapping of the pores, and release of the entrapped modifiable surface over other systems. TMB molecules. Released TMB is oxidized through In the present study, we report a target-responsive H2O2/HRP reaction, yielding a blue color. oligonucleotide-capped MSN based system immobilized Additional control experiments such as using on lateral flow test platform to detect Salmonella uncomplementary target DNA, capping the MSN enterica. In the presence of PCR-amplified target surface with uncomplementary probes were also sequence, the oligonucletide caps on the surface of MSNs conducted and verified the accuracy of the platform hybridize with the complementary target sequence which (Figure 2). results in opening of the pores and the release of previously loaded 3,3',5,5'-Tetramethylbenzidine (TMB), a chromogen molecule. Released TMB molecules are subjected to a redox reaction catalyzed by horse radish peroxidase (HRP) with the presence of H2O2 and yield a blue colored product for detection.
2. Materials and Methods Genomic DNA isolated from pre-enriched Salmonella enterica (typhimurium, enteritidis, and infantis) cultures was used as template DNA. Primers selectively amplify a 284 base-pair Salmonella specific Figure 2 Visualization of MSN- region were used in PCR, and the resulting amplicons based lateral flow strips under were applied as the target [1]. microscope. The 284 base-pair The external surface of TMB-loaded MCM-41 target sequence, mesoporous silica nanoparticles was functionalized with uncomplementary control (3-Aminopropyl) triethoxysilane, then separately capped 4. ConclusionsDNA, and only H2O2 were with single-stranded oligonucleotides (Probes 1 and 2) MSN-basedapplied lateral to flow the test strips platform 1, 2, and developed in that are complementary to the target amplicon. this study 3, can respectively. be reckoned as rapid, accurate and Components of the lateral flow strips (sample pad, cost- effective systems that can be utilized in nitrocellulose card, and backing pad) were placed on an laboratory and field or point- of-care environments. overlapping order. Prepared MSNs and HRP were immobilized on the strip, 4 mm and 6 mm away from the References sample pad, respectively (Figure 1). Pre-denatured target amplicons were mixed with H2O2, then applied to lateral [1] Rahn, K., et al. "Amplification of an invA gene sequence of Salmonella typhimurium by polymerase chain reaction as flow strips. a specific method of detection of Salmonella." Molecular and cellular probes 6.4 (1992): 271-279.
Figure 1 Schematic representation of a MSN-based lateral flow strip.
3. Results and Discussion The lateral flow and MSN platform developed in this study triggers the chromogen molecule release only in the presence of target sequence. When the denaturated
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0302
Molecularly Imprinted Polymer Based Microcantilever Sensor for the Selective Determination of Erythromycin in Water Resources M. Okan1*, Esma Sari2 and M. Duman1
1 Department of Nanotechnology and Nanomedicine, Institute of Science, Hacettepe University, Ankara, Turkey 2Department of Chemistry, Faculty of Science, Hacettepe University, Ankara, Turkey
*Presenter: [email protected]
Abstract fold lower binding affinities were observed, respectively. Erythromycin (ERY) is a class of antibiotic that is Reusability studies showed that the sensor system can be suggested as one of the priority drinking water used up to 3 times. The sensor system developed is low- contaminants at latest European Union Water Framework cost and is easily applicable by the user. This ERY Directive (EU-WFD). The main goal of this study is to specific MIP-NPs based nanosensor has the potential to be develop molecularly imprinted polymer (MIP) based a pioneer in the microcantilever mass sensing via microcantilever sensor for the selective determination molecular imprinting technology, as it is one of its very ERY in water resources. ERY imprinted polymeric first examples. nanoparticles (MIP-NPs) were synthesized with miniemulsion polymerization and their size was measured Acknowledgement: This study was supported by The to be 40±10 nm with high monodispersity. Scientific and Technological Research Council of Turkey (TÜBITAK). Project No: 113Z222.
Figure 5 Schematic representation of ERY imprinted polymeric nanoparticles.
The immobilization of MIP-NPs on the microcantilevers was accomplished by EDC/NHS activation, which provides monolayer covalent binding. The validation of microcantilever sensor was performed in air for a concentration range of 0.68- 67.94 µM, employing the dynamic sensing mode. Binding experiments showed that decrease in frequency was observed as the MIP-NPs were exposed to the template molecule. Results show that air studies performed with a cantilever that has a resonance frequency of 150 kHz works with 96% accuracy. The detection limit and the sensitivity of the sensor were determined as 1 µM and 1.58 Hz/pg, respectively. The control studies of MIP-NPs were carried out with competing agent Spiramycin (SPI) and non-imprinted polymeric nanoparticles (NIP-NPs). Namely, 8 fold and 3
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0104
Fabrication and Characterization of Miniaturized Optical Flow Cytometry Design
S. Murat1,2*, O. Bülend1,2, E. Çağlar1,2, B. Necmi1,2 and S. E. Mehmet3
1 UNAM - National Nanotechnology Research Center, Bilkent University, Ankara, Turkey 2 Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey 3 Department of Electrical and Electronics Engineering, Izmir Katip Celebi University, Izmir, Turkey
*Presenter: [email protected]
1.Introduction can be seen in figure 2 in detail. Laser source and optical fibers are placed through fiber slots which are at Flow cytometry (FC) is used in the diagnosis and the same size fibers so that it holds fiber tightly. monitoring of various diseases by inspecting, counting and sorting the particles, cells and/or tissues which are driven from patient. Optical flow cytometers use side scattered light (SSC), forward scattered light (FSC) and also fluorescence light (FL) to detect physical and chemical characteristics of flown particles. It is a technique where cellular parameters are extracted using a focused beam of light while they are in a fluid stream. Examples to such parameters are cell size, granularity, DNA content, counting of cells with specific antibody, and protein content. Figure 2 Fabricated FC chip, a. illustrative design, Commercial FC’s include bulk optics, which cause b. camera image general, and c. closer lookup alignment issues, require large amount of sample volume and are expensive to buy and maintain. Miniaturization of such microfluidic systems and 3.Conclusion combining fluidic, acoustic and fiber optical We were able to focus 6µm polystyrene beads with 3D components on the same glass chip is essential. hydrodynamic focusing using only one sheath fluid inlet In this study, we used femtosecond laser and one sample inlet. While focused particles passing microfabrication which is a maskless flexible and through laser light interrogation region, we measured simple technique for concept of lab-on-a-chip FSC and SSC signals with 5 mW optical power and 405 miniaturized devices and enables rapid prototyping, 3D nm wavelength of blue laser (figure 3). microstructuring into fused silica [1]. In future work, we are going to add FL measurement with fluorescence dye labeled particles and we will 2.Experimental Details improve on the signal processing capabilities with very Fabrication of miniaturized optofluidic FC microchip fast signal processing through LabVIEW FPGA. starts with, CAD design and followed by the femtosecond laser irradiation step through high precision automated XYZ stage on the one face of two fused silica samples at very high accuracy in 3D. Radiated samples are then immersed into HF solution in order to develop the microchannel. Finally developed surfaces are bonded to each other with fusion bonding using no adhesive layer using thermal annealing for 7 hours in high temperature furnace at 650°C. The inlet tubings are placed at last. Fabrication steps are illustrated in figure 1. Figure 3 FSC and SSC signals obtained by oscilloscope.
4.References [1] R. Osellame et al, Opt. Express 17, 8685-8695 (2009).
Figure 1 Femtosecond laser fabrication steps of FC
Solidworks design and camera images of fabricated chip
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0206
Biomimetic Carbon Dioxide Sequestration by Using Carbonic Anhydrase Attached Micromotors
Murat Uygun1,2*, Virendra V. Singh1, Kevin Kaufmann1, Deniz A. Uygun1,2, Severina D. S. de Oliveira1 and Joseph Wang1
1Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA 2Department of Chemistry, Adnan Menderes University, Aydın, Turkey
*Presenter: [email protected]
1.Introduction CaCO3
Carbon dioxide emissions are considered to be one of 3.Results the major contributions to climate change. Considerable efforts aimed at mitigating the accumulations of CO2 are The CA modified micromotors undergo efficient currently underway. New approaches are thus being propulsion at high speeds (e.g., 106 µms-1 using 2% developed to capture and sequester CO2, from effluents peroxide), with curved, circular, and self-rotating and the atmosphere, including adsorption on oxides, trajectories. zeolites, metal–organic frameworks, and ionic liquids. The mobile modified micromotors result in a high yield Each of these CO2 capture processes has its own of CaCO3, corresponding to a 90% efficiency within 5 disadvantages, such as high cost, high energy input, use min (Fig 1.). of harsh chemicals, and generation of pollutants.[1] Storing the dissolved CO2 (as solid calcium carbonate) is one of the most promising and environmentally reliable methods to reduce the amount of CO2 dissolved in water samples.[2] Recent advances in the field of synthetic nano/micromotors have expanded the performance, capabilities, and functionalities of these tiny vehicles. These developments have opened up a breadth of applications in diverse fields, ranging from energy generation, environmental cleanup, or disease diagnosis and treatment. For example, various detoxification reactions and sensing protocols have been shown to be rapidly accelerated by the autonomous motion of Figure 1 Micromotor-based CO2 sequestration and control catalytic micromotors and the enhanced fluid mixing experiments. CO2 sequestration efficiency in the presence [3,4] of A) unmodified motor, B) modified motor with generated by such movement. denaturated CA, C) static CA-modified motors, D) the Herein we describe a new approach based on carbonic static free CA; E) CA modified motors without sodium anhydrase (CA) functionalized micromotors for greatly cholate. F,G) CA-modified motors in pure water and in sea water, respectively. enhanced CO2 sequestration. This approach combines the biocatalytic activity of CA with the self-propulsion In conclusion, we have described a mobile CO2- scrubbing platform that couples the biocatalytic activity of chemically powered micromotors through CO2- saturated samples to act as highly efficient mobile of CA with the autonomous movement of chemically biocatalytic microscrubbers. powered micromotors to offer highly efficient and rapid 2.Methods CO2 sequestration. The self propelled CA- functionalized micromotors are shown to accelerate the COOH-PPy:PEDOT/Pt tubular micromotors were hydration of CO2 because of dramatically enhanced modified with the CA enzyme. The exposed surface fluid transport and continuous movement of CA. These carboxyl groups were activated using 1-ethyl-3-(3- factors result in significant improvements in the CO2 dimethylaminopropyl)-carbodiimide / N-hydroxy sequestration efficiency and reaction time. The practical succinimide (EDC/NHS) for conjugation with CA. utility of the new biomimetic micromotor approach has The catalytic decomposition of the hydrogen peroxide been demonstrated in seawater. fuel at the inner Pt layer of the micromotor generates the oxygen bubble thrust and leads to an efficient 4.References autonomous motion of the enzyme-modified [1] Ss G. Bhattacharjee, A. Kumar, T. Sakpal, R. Kumar, ACS microengine. The micromotor-based rapid “on the- Sustainable Chem. Eng. 2015, 3, 1205. move” biocatalytic hydration of CO2 to form a [2] T. R. Karl, K. E. Trenberth, Science 2003, 302, 1719. bicarbonate ion, followed by the precipitation of CaCO3 [3] V. V. Singh, F. Soto, K. Kaufmann, J. Wang, Angew. Chem. Int. Ed. 2015, 54, 6896 in the presence of CaCl2 were described. The enzyme [4] J. Wang, W. Gao, ACS Nano 2012, 6, 5745 CA is able to accelerate the inter conversion of CO2 to bicarbonate, leading to significantly higher amounts of
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0207
Single-Particle Imaging for Biosensor Applications
M. Yorulmaz1*, O. Avcı2, E. Seymour1 and M. S. Ünlü2, 3
1 ASELSAN Research Center, Biotechnology Research Program Department, Ankara, 06370, Turkey 2 Department of Electrical and Computer Engineer, Boston University, Boston, Massachusetts 02215, USA 3 Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
*Presenter: [email protected]
Abstract The interferometric detection of scattering signal Imaging of nanoparticles at the single particle level generated by the nanoparticle upon its excitation is an important subject of recent research especially with the light source is different than in the case of for the applications in bio-imaging and detecting the direct scattered light, such as the photovoltaics. Developing techniques in order to scattering signal in the dark field scattering image nanoparticles for early detection of diseases, microscopy. The signal measured using the solely such as viral infections and cancer, as well as the use scattering-based detection techniques scales as of nanoparticles for the treatment of certain types of follows: 2 cancers has gained considerable attention. 퐼 ∝ |퐸푠| (1) ASELSAN Research Center has recently launched where 퐼 is the direct scattering signal and 퐸푠 is 3 research efforts in biotechnology and aims to scattering field. As 퐸푠 scales with 푟 , the direct develop an in-vitro point-of-care biosensor that can scattering signal scales with 푟6 and drops notably be used for diagnostic purposes. For this purpose, an for nanoparticles with small sizes. For example, it imaging technique that is sensitive, easy-to- becomes very challenging to image gold implement, low-cost, and easy-to-miniaturize is nanoparticles with sizes below 40 nm using direct essential. Such a technique will be useful to develop scattering signal. biosensors which will transform into portable On the other hand, the intensity measured using an medical imaging and detection devices, allowing for interferometric system is as follows: 2 disease diagnostics in remote locations and 퐼 ∝ |퐸푠 + 퐸푟| ∝ 2|퐸푠||퐸푟|cos (ɵ푟푠) (2) subsequent planning for clinical therapy. where 퐸푟 is the reference field and the interference Optical interferometric techniques have proven signal that is the cross-term scales with 푟3. utility in sensitive imaging of individual Therefore, interferometric methods allows for nanoparticles in wide-field. We initially plan to imaging nanoparticles with smaller sizes. Using this adopt the biosensor developed by Prof. Dr. Selim technique, it is possible to image dielectrics with Ünlü and his group. We will then study and smaller scattering cross-sections than those of gold implement various optical schemes to improve the nanoparticles. The scattering image of 104 nm sensitivity of this biosensor, targeting to detect polystyrene beads is shown in Figure 2. smaller biomolecules that would normally go undetected with the current system. We put efforts in creating practical, robust, and cost- effective solutions for non-laboratory environments. Single-Particle Interference Reflectance Imaging Sensor (SP-IRIS) has been successfully applied in detecting synthetic nanoparticles and viruses [1]. In spite of the strong imaging capability of the technique, it does not require advanced optics parts. Figure 2 The scattering signal of 104 nm polystyrene Moreover, it can be developed using halogen light beads. sources instead of expensive lasers. It requires the Our goal is to enhance the sensitivity of this use of a silicon-silicon dioxide substrate as a technique through integration of polarization optics, common-path interferometer. The schematic of the and achieve accurate sizing as well as shape and optical setup is shown in Figure 1. orientation determination of nanoparticles in conjunction with the physical theory [3] based forward model and various reconstruction models. This enhancement will allow us to extend the use of this technique for detecting a wide variety of diseases including cancer using minute amounts of sample. References [1] Avci et al. Sensors, 15 (7), 17649-17665 (2015) [2] Daaboul et al. Nano Letters, 10 (11), 4727-4731. (2010) Figure 1 The schematics of SP-IRIS. (Adapted from Ref. [3] Avci et al. Optics Express 24 (6), 6094-6114 (2016) [2])
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0103
miRNA Sensing Self-Propelled Hybrid Micromotors
Lutfi Oksuz1, Nilgün Dükar2*, Filiz Kuralay2, Gözde Yurdabak Karaca3, Umran Koc1, Emre Uygun1 and Aysegul Uygun Oksuz3
1Department of Physics, Faculty of Arts and Sciences, Suleyman Demirel University, 32260 Isparta, Turkey 2Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey 1Department of Chemistry, Faculty of Arts and Sciences, Suleyman Demirel University, 32260 Isparta, Turkey
*Presenter: [email protected]
Abstract drying, hybride powders coated with platinum (Pt) by rf Self-propelled micromotors have enabled exciting Magnetron Sputtering method under 6 minutes and 25 applications in biomedical field such as delivering Watt power. The effects of the surfactant and the fuel drugs, nanoscale transport and assembly [1]. concentration onto the speed of micromotors were Particularly, chemically powered micro/nanomotors investigated. based on different chemical compositions and structures that are capable of moving autonomously in the Acknowledgments: This Project is supported by presence of hydrogen peroxide fuel. Especially, TÜBİTAK (Project No: 1150098). F. Kuralay fabrication of nano and micro propellant systems acknowledges Turkish Academy of Sciences (TÜBA) as featuring specific cell recognitions in a short time frame an associate member and TÜBA-GEBİP programme. is highly anticipated. Ability of micromotors for selective capture, and isolation of cancer cells based on References the selective binding and transport ability was demonstrated [2,3]. miRNAs are gaining recognition as [1] S.S. Banerjee, A. Jalota-Badhwar, K.R. Zope, K.J. critical regulators of many biological processes, Todkar, R.R. Mascarenhas, G.P. Chate, G.V. Khutale, A. emerging as therapeutic targets for treating disease, Bharde, M. Calderon, J.J. Khandarea, Nanoscale 7 especially cancer cells [4]. (2015) 8684. In this study, new tungsten oxide/poly(2-fluoroaniline) [2] S. Balasubramanian, D. Kagan, C.J. Hu, S. (WO3/P2FANI) based hybride was used to obtain Campuzano, M.J. Lobo-Castañon, N. Lim, D.Y. Kang, WO3/P2FANI/Pt micromotors which propelled M. Zimmerman, L. Zhang, J. Wang, Angew. Chem. Int. catallytically using H2O2 fuel. Biosensing properties of Ed. 50 (2011) 4161. the micromotors were investigated for target miRNA [3] D. Kagan, S. Campuzano, S. Balasubramanian, F. sequences. Fluorescence intensity and speed of Kuralay, G.-U. Flechsig, J. Wang, Nano Letters 11 micromotors were analyzed using NİKON Eclipse Optic (2011) 2083. LV100ND Microscopy. [4] J. Condea, E.R. Edelmana, N. Artzia, Advanced Hybride structure was obtained by using rf rotating Drug Delivery Reviews 81 (2015) 169. plasma technique. Then, hybrid powders were dispersed in the solvent and dropped onto cleaned glass. After
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0307
Biosensing Strategy for Detection of Bacterial Susceptibility
Against Beta Lactamases
P. Kara1*, A. N. Yurtman2, H. Taslı2, M. Limoncu2 and M. Ozsoz3
1 Ege University, Faculty of Pharmacy, Analytical Chemistry Department, 35100, Bornova- Izmir, Turkey 2 Ege University, Faculty of Pharmacy, Pharmaceutical Microbiology Department, 35100, Bornova- Izmir, Turkey 3 Gediz University, Faculty of Engineering, Nanotechnology Department , Turkey
*Presenter: [email protected]
Introduction An antibiotic based electrochemical biosensor for direct detection of beta lactamase susceptibility against cefotaxim in E. coli cell was developed in this study. Screen printed gold electrodes (AuSPE) were used as sensor surface and Electrochemical impedance spectrometry (EIS) was used as transducer. Cefotaxime Figure 1. Schematic presenstation of the study procedure. antibiotic was immobilized onto AuSPE’s and antibiotic modified AuSPE surfaces were incubated with bacteria Results and Discussion cell culture solution including whole bacteria. Clinical E. coli isolates that excrete extended spectrum beta lactamase (ESBL) which were sensitive and resistant to cefotaxime have been used for the detection. Staphylococcus aureus and pseudomonas auroginosa isolates were used as negative controls. A non- beta latam antibiotic vancomycine was also used for the detection of biosensor selectivity. β-lactamase type Figure 2. EIS datas of cefotaxim coated AuSCPE; before c) and after incubation with b) cefotaxim sensitive, a) cefotaxim resistant E. coli enzymes are produced by some bacteria, which are bacteria. mainly responsible of catalyzing the hydrolysis of β- lactam antibiotics that causes in bacteria resistance to Conclusion these antibiotics [1]. β-lactamases catalyze the An impidimetric cefotaxim cytosensor for direct hydrolytic degradation of the amide bond in the four detection of beta lactamse activity and resistant in E. membered β-lactam ring in β-lactam antibiotics, which coli strains was developed. The selectivity of biosensor inactivates the β-lactam antibiotics. Extended-spectrum was evaluated by using non- beta latam antibiotic β-lactamases (ESBLs), are often the cause for resistance vancomycine and Staphylococcus aureus and to newer cephalosporins and monobactams in the pseudomonas auroginosa isolates. It was shown that the members of the family of Enterobacteriaceae. ESBLs designed biosensor is capable of label free; low-cost, have been widely found worldwide [2-4]. Several fast and reliable detection. Furthermore system can be methodologies for rapid and reliable detection of beta applied to produce susceptibility test kits. lactamase activity were studied including, enzyme- linked immunosorbent assay [5], spectrophotometry [6], References chemiluminescence [7] and mass spectrometry [8] [1] Z. Xu, H.Y. Wang, S.X. Huang, Y. L. Wei, S.J. Yao, Y.L. Guo, Anal. Chem., 82, (2010), 2113 -2118. techniques. The goal of our study is to develop a [2] P.A. Bradford, Clin. Microbiol. Rev., 14, (2001), 933-951. biosensor for rapid, label free, high-throughput bacterial [3] B.S. Kocazeybek, Chemother., 47, (2001), 396-408. antibiotic susceptibility determination. A.M.Hujer, K.S. A.M., Keslar, N.J. ,K.S. Dietenberger, C.R. ,N.J. Materials&Methods Bethel, A. Endimiani, R.A. Bonomo, Detection of SHV beta- lactamases in Gram-negative bacilli using fluorescein-labeled Bacteria Culture: E. coli American Type Culture antibodies, BMCMicrobiol, 2009, 9, 46 -49. Collection (ATCC) 25922 was used as the reference [4] Z.Y.K. Naomi, Simple Photometric Assay of f-Lactamase Activity, strain. The broth microdilution test was performed by Antimicrobial Agents and Chemotherapy, 1972, 2, 356 -359 using sterile, disposable, multiwell microdilution plates [5] P. Liang, R.I. Sanchez, M.T. Martin, Electrochemiluminescence based detection of beta lactam antibiotics and beta lactamases, Anal. (96 U-shaped wells), and Mueller–Hinton broth (BD, Chem., 1996, 68, 2426 -2431. France) two fold serial dilutions were prepared in [6] M.T. Cancilla, M.D. Leavell, J. Chow, J.A. Leary, Mass microdilution plate. spectrometry and immobilized enzymes for the screening of inhibitor Biosensor Preparation: The illustration of the study libraries, Proc.Natl.Acad.Sci. 2000, 97(22), 12008–12013. [7] J.M. Park, J.I. Kim, H.W. Song, J.Y. Noh, M.J. Kang, J.C. Pyun, procedure is shown in Figure 1. Biosensors & Bioelectronics, 2015, 71, 306 -31
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0313
Functional GQDs nano-composite fabricated for direct and rapid detection of BPA with paper based fluorescent system
Recep Üzek1,2*, Esma Sari1,2, Serap Şenel1, Arben Merkoçi2
1 Department of Chemistry, Hacettepe University, 2 Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology
*Presenter: [email protected]
Abstract In summary, we have reported several significant novelty In this study, we developed fluorescent sensor for the as follows. First, the paper-based sensing system, hıgh sensitive and selective detection of BPA. NPs were selectivity of MIP and fluorescence property of GQDs prepared by mini-emulsion polymerization and GQDs were successfully combined to provide selective, were prepared by hydrothermal pyrolysis. GQDs were sensitive, rapid and inexpensive sensing strategy for BPA attached to the NPs by EDC/NHS coupling. Fluorescent monitoring. Besides, we have reported a sensing nanosensor was characterized by using Zetasizer, platform than can be exploited with small volumes of UV−vis and photoluminescence spectra, TEM and FTIR. nano composite and BPA solution. In this respect, this The nanosensor gave response to BPA as an material could be easily produced for application in enhancement in the PL intensities. The detection limit fields of research and industrial because it is easy to (LoD) and selectivity using the fluorescent nanosensor synthesize, cheap, non-toxic and environmentally was found to be comparable to the other techniques. For friendly. In addition, sensing system can be easily example, the LoD of SERS of core-shell Au extended to the monitoring not only for pollutants but nanoparticles was demonstrated to be 0.53 µM and also for bıomolecule by simply choosing different competed with other methods such as functional monomer for the molecular imprinting chemiluminescence, direct irradiation and UV-vis techniques. methods which usually detect BPA with 0.1 nM LoD.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0211
Detection of Micro and Nanoparticles in a Microfluidic Device Using Resistive Pulse Sensing Technique
S. Resul1*, E. Caglar2,3 and D. Memed4
1 Department of Mechanical Engineering, University of Siirt, 2 UNAM - National Nanotechnology Research Center, Bilkent University, Ankara, Turkey 3Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey 4 Department of Bioengineering, University of Hacettepe
*Presenter: [email protected]
1.Introduction 3.Results Resistive pulse sensing (RPS) technique, in 1996, has been initially introduced for single-stranded RNA and Figure 2 demonstrates DLS measurement results of the DNA molecules detection using a biological α- particles including size distribution and diameter of, and hemolysin pore [1]. Then, the technique has been presents a mean value. According to results, mean employed for high-throughput detection of micro and diameter of the particles is found to be 468.9 nm. nanoparticles. Since, nanoparticles are used in many However, when the diameter of the particles is application domains such as cosmetics, photovoltaics measured using SEM, it is found to be approximately and medicine [2]. On the other hand, dynamic light 360 nm. Since DLS presents a mean value for particle scattering (DLS) method is commercially used to obtain diameter. As it can be seen in Figure 3 while some of diameter and size distribution of the nanoparticles in the particles are agglutinated, others not. suspension. However, accuracy of this technique is relatively low compare to RPS technique [2] because, while RPS detects and counts nanoparticles individually, DLS measures scattered light with fluctuations caused by Brownian Motion, which is not observable if particle diameter is greater than 10 µm. Here, we present the RPS technique to detect and count micro particles individually as a consequence of blocking ionic electrical current. We also synthesised silica nanoparticles using tetraethylorthosilicate (TEOS) method and counted them using DLS and compared the Figure 2 DLS measurement results results with those obtained from SEM.
2.Fabrication Method Two photo-definable epoxy SU-8 thicknesses were coated on silicon wafer and then patterned using standard lithography. Obtained depth of the whole microfluidic structure is 35 µm, and wide of microconstriction (MR) is 20 µm. Polydimethylsiloxane Figure 3 SEM image of silica nanoparticles (PDMS) resin and curing agent are mixed well at ratio of 10:1 and degassed for 1 hour and then poured to top 4.Conclusion and Discussion of fabricated mold. Microfluidic channel is bonded onto In this study, we show that DLS method is not always a a glass where gold readout electrodes are coated using proper way to determine size distribution and diameter e-beam evaporation. Figure 1 shows schematic image of of the particles when the results obtained from DLS are microfluidic channel and microconstriction image of compared with those obtained from SEM or RPS fabricated microfluidic device under microscope. technique. RPS technique enables very reliable way for particle detection since the technique measures the particles individually.
5.References [1] Kasianowicz, John J., et al. Proceedings of the National Academy of Sciences (1996): 13770-13773. Figure 1 a) Schematic image of microfluidic channel [2] Fraikin, Jean-Luc., et al.."Nature nanotechnology 6.5 (2011): 308- b) Microconstriction image of fabricated microfluidic 313. device under microscope (scale bar- 100 µm)
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0106
Synthesis of Functionalized Fluorescent Carbon Nanoparticles as Artificial Enzymes and Signaling Tools for Their Use in Bioanalysis
G. Rükan1,2, *, A.Ö. Melis1, B. Burcu1 and B. Dilek2,3
1 Functional Nanomaterials Lab, Chemical Engineering Dept., Mersin University, Çiftlikköy Kampüsü 33343, Mersin, Turkey 2 Mersin University Advanced Technology Education, Research and Application Center (MEITAM), Mersin University, 3Mersin University Faculty of Pharmacy Department Of Pharmaceutical Toxicology
*Presenter: [email protected]
1.Introduction Characterization of fluorescent CNPs Ultraviolet-visible (UV-Vis) spectra of CNPs were Fluorescent nanoparticle-based biolabels are promising recorded using an Shimadzu UV-1800 UV-VIS tools which could give pave the way to develop new spectrophotometer ). X-ray diffraction (XRD) analyses medical diagnostic tools based on their advanced optical were performed in a Rigaku Smartlab Intelligent X-ray properties with extreme resistance to photobleaching diffractometer (XRD). Fourier transform infrared compared to conventional molecular probes. Although, (FTIR) spectroscopy was performed in a range of 400– significant progress has been made in nanoparticle- 4.000 cm−1. Transmission electron microscopy (TEM; based biological labelling and imaging, the concern JEOL) was used to determine the size and morphology about the possible toxicity of these materials at of the dispersed FCNPs. Fluorescence spectra of particle functional concentrations has severely limited their solutions were measured using a Varian Cary Eclipse widespread use in clinic [1,2]. Fluorescence Spectrophotometer. Carbon dots are new member of carbon based nanostructures. They can be synthesized from several carbon sources and at nanosize show auto-fluorescence. This materials with low photo-bleaching, low cytotoxicity, biocompatibility are of great interest due to their potential in many fields requiring non hazardous materials.(4) Here, we report fluorescent carbon nanoparticle-based nanolabels which could be suitable for bio-imaging, diagnostics as fluorescent nanolabel as well as due to surface functional moeities, they function as enyzme mimitics for oxidation reactions. To do so, we used different carbon sources including molasses Figure 1. True colour photographs of fluorescence and some industrial co-products as carbon source and emission from synthesized carbon nanodots mixed them with different pigments, metals and so on to (Ext./400nm). Core image has been taken from Ref [4]. obtain various carbon nanodots with so many different Analysis properties. Synthesized fluorescent carbon nanoparticles Presence of dopamine and Mercury from liquid were further conducted to bioassays for the analysis of ssamples was measured by evaluating the changes in the several medically important molecules such as fluorescence response of different carbon nanoparticles Hydrogen Peroxide, Dopamine and Mercury. while H2O2 analysis was carried out by measuring the
color change of ABTS following a standard peroxides 2.Materials and Methods test. Synthesis of FCNPs The synthesis of FCNPs was accomplished according to Acknowledgements. This study is partially funded by the method described previously by Mukherjee [3]. A Mersin University Scientific Research Project Unit homogeneous suspension of carbon source was obtained (Project No: 2016-AP4-1791) without aggregation by vigorous mixing.. The mixture was maintained at 250°C for 45 minutes until a dark, 3.References caramelized, semi-solid texture was obtained. The (1) Liu, Q.; Chen, M.; Sun, Y.; Chen, G.; Yang, T.; Gao, Y.; Zhang, resulting material was dissolved in 2 mL of MilliQ- X.; Li, F.. Biomaterials 2011, 32 (32), 8243–8253. water (Millipore Inc., Ω = 18 MΩ·cm). The suspension (2) Schütz, M.; Steinigeweg, D.; Salehi, M.; Kömpe, K.; Schlücker, was centrifuged at 5.000 rpm for 30 minutes; the final S. Chem. Commun. 2011, 47 (14), 4216–4218. (3) Mukherjee, P.; Misra, S. K.; Gryka, M. C.; Chang, H.-H.; Tiwari, product was vacuum-dried. The synthesis of the carbon S.; Wilson, W. L.; Scott, J. W.; Bhargava, R.; Pan, D. Small 2015, nanoparticles were monitored by irradiating with a 365 11 (36), 4691–4703. nm UV light source. Further characterizations of the (4) Demchenko, A. P.; Dekaliuk, M. O. Appl. Fluoresc. 2013, 1 (4), synthesized CNPs were performed as described above. 042001.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0107
Preparation of Polypyrrole based electrodes for Glucose 6-phosphate determination
S. Sahin1*, I. Ozmen1, G. Yıldırım2 and S. Percin Ozkorucuklu2
1 Department of Chemistry, Suleyman Demirel University, 2 Department of Molecular Biology and Genetics, Istanbul University,
*Presenter: [email protected]
Introduction concentration
The determination of the glucose 6-phosphate (G6P) in blood or human tissue informs about many diseases associated with glucose 6-phosphate dehydrogenase (G6PD) deficiency [1]. Therefore, there are several studies on improving of biosensor for glucose-6- phosphate measurement. To date, developed biosensors have based on combinations of G6PD and different mediators or enzymes [2]. The aim of this study was to prepare G6P biosensors which contain polypyrrole (PPy) and Fe3O4-Chitosan (CS) nanoparticles and optimize several parameters for maximum response. Figure 1 SEM images of naked pencil graphite Methods electrode (a) and electrochemically prepared PPy (b) Ppy and Fe3O4-CS-PPy electrodes were prepared and Fe3O4-CS-PPy (c) electrodes onto pencil graphite electrochemically onto pencil graphite electrode. Electrochemical synthesis was performed with pyrrole References in acidic solution at constant current density of 0.35 mA [1] S. Banerjee, P. Sarkar, A. P. F. Turner, cm-2. Surface morphology of electrodes was determined Amperometric biosensor based on Prussian Blue with SEM analysis. Then, glucose 6-phosphate nanoparticle-modified screen-printed electrode for dehydrogenase (G6PD) was immobilized on electrodes estimation of glucose-6-phosphate. Anal. Biochem. via glutaraldehyde. Optimum enzyme immobilization 439(2013) 194–200. conditions were determined for two electrodes. [2] Y. Cui, J. P. Barford, R. Renneberg, Development Chronopotentiometric curves of electrodes were of a glucose-6-phosphate biosensor based on recorded at current density of 0.25 mA cm-2 for different coimmobilized p-hydroxybenzoate hydroxylase and G6P concentrations. Various optimization studies, such glucose-6-phosphate dehydrogenase. Biosens. as pH, enzyme concentration, and NADP+ Bioelectron, 22(2007) 2754–2758. concentration, were performed to obtain maximum responses for G6P measurement. To determine the usefulness of the prepared G6P biosensor, human blood serum samples were spiked with known concentrations of G6P and were used as analytes for the measurements.
Results As a result, Ppy and Fe3O4-CS-PPy electrode showed a broad lineer response to G6P in the range of 0,025 to 0.25 mM and 0.005 to 0.1 mM, respectively. The results of optimization studies are given in Table 1. Surface morphology of Fe3O4-CS-Ppy and PPy electrode is shown in Figure 1. Table 1 Optimization results Paramet Fe O -CS- PPy 3 4 ers PPy pH 8.5 8 Enzyme 2 U 1 U concentration NADP+ 1.25 mM 1.25 mM
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0209
Detection of Alzheimer`s Protein on Polycarbonate Nanopillared Films by Using Surface Enhanced Raman Spectroscopy
Sevde Altuntas1*, Can Simon Pervane2 and Fatih Buyukserin3
1Biomedical Engineering Graduate Program, TOBB Univ. of Econ. & Technology, Ankara 06560, Turkey 2Institute of Complex Systems Simulation, University of Southampton, Southampton SO171BJ, United Kingdom 3Department of Biomedical Engineering, TOBB Univ. of Econ.& Technology, Ankara 06560, Turkey
*Presenter: [email protected]
Introduction a mold. To AAM column structure, three different types Alzheimer`s disease is responsible for neuronal damage of PC arrays were fabricated to enhance SERS signals. of cerebral cortex and hippocampus because of Amyloid The PC films were then decorated with Au and β 1-42 protein accumulation. The protein detection Thioflavin – T for detection Amyloid-β 1-42 protein. studies have gathered around ELISA assay and PCR (Figure 1). The protein detection studies were conducted assays which are expensive, require specialized in water and artificial human saliva. SEM, SERS, FTIR, personnel and can contain complex protocols. On the fluorescence microscopy and contact angle other hand, Surface-enhanced Raman Spectroscopy measurements were carried out for the characterization (SERS) can potentially allow even single molecule of different surfaces and further demonstration of the detection in solutions or solid surfaces. In addition, protein attachment. In addition to experimental study, SERS signal from a target molecule can be further computational enhancement studies were carried out by increased by using nanopatterned surfaces when using COMSOL Multiphysics. compared to smooth counterparts. Moreover, Raman The results will be presented comparatively. signals are specific to molecules, so one can comment about content of a sample. For this reason we focused Alzheimer protein detection on nanopatterned polymer surface by using SERS techniques.
Materials&Methods Nanoporous anodic aluminum oxide membrane (AAM) was synthesized by using two step anodization method from high purity aluminum. According to electrolyte type, anodization time, voltage values and temperature, AAM thickness, column structure or pore size were arranged. The nanoporous film was coated with n- octadecyltrichlorosilane to decrease its surface energy. AAM was coated polycarbonate (PC) solution (wt/v 6%) by using drop-casting method. After solvent evaporation, the PC film was removed from the surface. The nanopatterned surface was coated with gold (thickness: 10, 20 and 30 nm) by using thermal evaporator (Nanovak, NVTS 400). After gold coating process, the polymer films were decorated with different Figure 1 SEM images of nanopatterned surface (a), and concentrations of Thioflavin – T which is widely used branched nanopatterned surface (b). SERS spectrum of to visualize and quantify the presence of misfolded Thioflavin – T modified nanopatterned and flat PC surface (c). protein aggregates called amyloid. SERS technique was used for protein and Thioflavin – T detection (DeltaNu Conclusion Examiner Raman microscope. Laramie, WY). To conclude, SERS intensity of multibranched According to decrease of Thioflavin – T signal, amount nanopatterned surface is much higher than other of the amyloid protein were determined. Limit of samples because of the high hot spot probability. -5 detection was found 0.5 pg/ ml for the protein. Besides SERS results of 20 nm gold coating and 10 M Thioflavin – T decoration are more favorable to Results measure amyloid amount. In addition to all of them, the In this context, our study proposes to fabricate COMSOL results will be shared during presentation. diagnostic test models that utilize Au-coated Acknowledgment: This work was supported by The nanopatterned PC surfaces modified with Thioflavin - T Scientific and Technological Research Council of to detect low concentrations of Amyloid-β 1-42 protein Turkey (TUBITAK) Grant No: 214Z167. in water and artificial saliva medium by the enhancement of protein SERS signal. Nano patterned PC surface was fabricated by using nanoporous AAM as
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0312
Smart Surface Based Guiding of Microdroplets Over Laser Ablated Sinusoidal Rail
Z. Rashida, Y. Morovab, B. Yalızayb, U. C. Çoşkunc, A. Ertena, A. Jonasb and A. Kiraza,d*
a Koç University, Department of Physics, Sariyer, Istanbul b Istanbul Technical University, Department of Physics, Maslak, Istanbul c Istanbul Technical University, Department of Mechanical Engineering, Maslak, Istanbul d Koç University, Department of Electrical and Electronics Engineering, Sariyer, Istanbul
*Presenter: [email protected]
Abstract
We present a method of water droplet generation using Droplet-based microfluidic systems have been shown to oil as a host liquid using T-junction geometry and be compatible with many chemical and biological guiding of those droplets on hydrophilic glass slide rail reagents and capable of performing a variety of ‘‘digital surrounded by hydrophobic PDMS surface. The fluidic’’ operations that can be rendered, programmed trajectory of different sizes of the droplets is determined and reconfigured. This platform has dimensional scaling using cross correlation algorithms for different depths of benefits that have enabled controlled and rapid mixing the track over the coated cover glass slide. The of fluids in the droplet reactors, resulting in decreased coordinates of the track, on the other hand, are reaction times. This, coupled with the precise generation evaluated by scanning the whole image along the two and repeatability of droplet operations, has made the dimensions and detecting the color transition while droplet-based microfluidic system a potential high moving from left to right along the rail. The distance throughput platform for biomedical research and between the centers of droplet path and track is applications. calculated for several droplets and presented in the form of histograms to find the quality of guiding for three different specimen.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0105
Dielectrophoretic Spectra of Polymorphonuclear White Blood Cells
Z. Çağlayan1*, Y. Demircan Yalçın1, 3, G. Özkayar2, 3, E. Özgür3 and H. Külah1, 3, 4
1 Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara, Turkey 2 Department of Biomedical Engineering, Middle East Technical University, Ankara, Turkey 3 Mikro Biyosistemler Inc. 4 METU-MEMS Research and Application Center
*Presenter: [email protected]
1.Introduction was applied and the motion of cells was recorded with a CCD camera (SONY/DXC-107AP). Velocity Dielectrophoresis (DEP), is a sensitive and rapid of cells was determined through Meazure and method, utilized for separation of dielectrically different VirtualDub. When velocity of the solution is zero, cells, even with similar sizes in a label-free manner. For velocity of cells can be directly related to cell separation through DEP, dielectric properties of the Re(푓 ) 훻|퐸2|, keeping 훻|퐸2| as same for each cell. cells should be known. In this study, dielectrophoretic 퐶푀 WBCs can be examined in two main groups as spectra of polymorphonuclear white blood cells (WBCs) polymorphonuclear WBCs (neutrophils and were investigated. eosinophils) and mononuclear WBCs (lymphocytes,
monocytes and basophils). The first three most 2.Theory and Design abundant WBC types are neutrophils, lymphocytes Dielectrophoresis is described as the relative movement and monocytes in the order, forming the largest of particles and suspending medium in nonuniform portion of total WBCs in blood [2]. Therefore, to get electric field. Time averaged DEP force for spherical knowledge about DEP spectra of WBCs, it is particles is: decided to start with polymorphonuclear WBCs. For tests, whole blood is taken from healthy woman 3 2 퐹퐷퐸푃 = 2휋휀푚푟 푅푒(푓퐶푀)훻|퐸 | (1) donors. After treating the blood with Ficoll, developed OptiPrep procedure is applied to get where r is the radius of the cell, 훻|퐸2| is the gradient of polymorphonuclear and mononuclear WBCs separately. The procedure is based on the formation the external electric field magnitude square, 휀푚 is the permittivity of the medium and 푅푒(푓 ) is the real part of density gradient. The obtained velocity vs. 퐶푀 frequency profiles for two donors with standard of the Clausius-Mossotti factor. According to 푓 , 퐶푀 deviations can be seen from Figure 2. particles can be either pulled towards stronger electric field region (positive DEP-pDEP) or pushed towards 45 40 donor 1 donor 2 weaker electric field region (negative DEP-nDEP) [1]. 35 A DEP spectrum device, with reciprocal V-shaped 30 planar-electrodes was utilized to obtain DEP spectra of 25 20 polymorphonuclear WBCs by using pDEP effect. The 15 gap between electrode tips is 20μm. The angle between (µm/sec) velocity 10 arms of electrodes is 30˚. A parylene chamber 5 0 (h=20μm) was constructed to create reservoir for cell 4,5 5,5 6,5 7,5 8,5 solution. The schematic and the fabricated views of this frequency (10^x) device can be seen from Figure 1. Figure 2 Velocity vs frequency profile of polymorhonuclear WBCs of two healthy donors
As a future work, remaining dielectrophoretic spectra of mononuclear WBCs, will be examined and compared with polymorphonuclear WBCs. With this way, DEP spectra of WBCs will be obtained.
4.References Figure 1 Schematic view (a) and the fabricated [1] Y. Demircan, A. Koyuncuoğlu, M. Erdem, E. Özgür, U. Gündüz, view (b) of DEP spectrum device and H. Külah. “Detection of Imatinib and Doxorubicin Resistance in K562 Leukemia Cells by 3D-Electrode 3.Results and Discussion Contactless Dielectrophoresis,” Transducers, 2013, pp. 2086- 2089 For each test, 4µl cell suspension was put into the [2] White Blood Cell Count (WBC) and Differential.” Internet: reservoir and waited until solution motion stopped. http://www.rnceus.com/cbc/cbcwbc.html, 2013 [10.11.2015]. 10Vpp at 15 different frequencies (100 kHz-50 MHz)
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Oral Presentation – OP0204
Point-of-Care Measurement of Erythrocyte Sedimentation Rate
Z. Işıksaçan1* and Çağlar Elbüken1
1 Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center, Bilkent University, Ankara, Turkey
*Presenter: [email protected]
Introduction Erythrocyte aggregation (EA) is a process where erythrocytes form face-to-face structures at stasis or low shear rates. Erythrocyte sedimentation rate (ESR) is a 1- hour clinical test for inflammation screening [1]. Here, we report a point-of-care device that measures ESR from EA using 40 µl fingerstick blood in 1.5 minutes with a novel measurement method.
Methods The measurement system consists of a disposable cartridge and a portable opto-electro-mechanical analyzer. The cartridge channel is illuminated with an infrared light. A constant pressure is applied to the Figure 1: Standard ESR versus microfluidic ESR test channel for complete disaggregation. As the results using different dextran concentrations erythrocytes aggregate, the transmitted light intensity from the erythrocytes in the channel is recorded for 1.5 min. The intensity level is lowest at complete disaggregation and highest at complete aggregation. From this data, ESR is measured.
Results and Discussion For experimental verification of the measurement method, first, we added dextran polyglucose, an aggregation inducer, of different concentrations in blood samples obtained from a healthy male volunteer. We measured the ESR of the samples using our system and the conventional 1-hour test. We showed that the amplitude of the transmitted signal is in correlation with the conventional test result with R2 of 0.98 using linear Figure 2: Standard ESR versus microfluidic ESR test regression. results using blood samples from different patients Secondly, we used blood samples from three patients. The ESR values were measured using our system and Acknowledgement the standard Westergren method. We showed that the correlation between the two methods is very good with The authors acknowledge support from The Scientific R2 of 0.99 using linear regression. and Technological Research Council of Turkey (TUBITAK project no. 213S127). Conclusion References This work demonstrates that our point-of-care reliably measures ESR from EA. To the best of our knowledge, [1] “Red Blood Cell Aggregation,” O. Baskurt, B. Neu, this is the most rapid ESR measurement method H.J. Meiselman, CRC Press (2011). provided in the literature. The measurement takes only 1.5 minutes (in comparison to 1 hour in the conventional test) and uses only 40 µl whole blood (as opposed to 2 ml blood used in the conventional test). When a high speed camera is integrated onto the cartridge, we can also monitor EA process to better understand the mechanism of this physiological phenomenon.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster
Presentations
Poster Presentation – PP0101
Highly monodispersed droplet generation using a microfluidic system
Ali Kalantarifard1,2* and Çaglar Elbuken1,2
1 UNAM - National Nanotechnology Research Center, Bilkent University, Ankara, Turkey 2 Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction 3. Results and Discussion During the last decade droplet generation has become a significant field of research because of its wide Figures 2 and 3 show the results of droplet area applications in science and microscale engineering. The distribution in numerical and experimental model ability to generate highly monodispersed microdroplets respectively. Moreover, as it is shown in Table 1, has applications in various fields such as chemical, coefficient of variation of droplets area for syringe biological and medical study [1]. One of the needs to pump case is higher than the pressure pump case in both achieve monodisperse droplets is having stable and models. uniform flow rate of the fluids which are supplied by the pumps [2]. There are mainly two types of pumps Syringe Pump-Numerical model Pressure Pump- Numerical model
used for making droplets: pressure-driven pump and 30 20
20 15 syringe pump (Figure 1). By using pressure-driven 10
10 Count Count 5 pump, two immiscible fluids can be supplied to the 0 0
inlets of the chip by pressurized air. For syringe pump,
1,62E+05 1,63E+05 1,64E+05 1,65E+05 1,66E+05 1,67E+05 1,68E+05 1,69E+05
1,70E+05 1,71E+05 1,72E+05 1,73E+05 1,74E+05 1,75E+05 1,76E+05 fluids are supplied to microchannel by pushing the 1,69E+05 plunger by the gear motor [3]. In this study, the Droplet area (µm2) Droplet area (µm2) performance of these two pumps is compared for generating monodisperse droplets. The same number Figure 2 Droplet area in numerical model and size of droplets are investigated numerically and experimentally to compare the results in terms of Syringe Pump- Experimental model Pressure Pump- Experimental model
monodispersity. 20 40
15 30
10 20 Count 5 Count 10
0 0
1,72E+05 1,61E+05 1,63E+05 1,64E+05 1,66E+05 1,67E+05 1,69E+05 1,70E+05
1,60E+05 1,64E+05 1,68E+05 1,72E+05 1,76E+05 1,80E+05 1,84E+05 1,88E+05 Droplet area (µm2) Droplet area (µm2)
Figure 3 Droplet area in experimental model
Figure 1 Schematic of syringe pump and pressure Table 1 Coefficient of Variation of droplet area pump systems Experimental Numerical 2. Experimental Setup Syringe Pressure Syringe Pressure Pump pump pump pump pump Experimentally droplet generation is performed by CV% 1.5 3.87 0.63 1.28 using syringe pump and pressure pump. For both experiments, the two immiscible fluids are silicone oil 4. Conclusion (carrier fluid) and deionized water (dispersed phase). The numerical and experimental results show that by The PDMS microchannel is fabricated using soft lithography and then bonded on the glass slide. using syringe pump we can obtain more monodispersed droplets. Also, according to results in both cases, CV Numerical Simulation for experimental method is higher than numerical, due to the fluctuation of flow rate and pressure induced at The same geometry as the fabricated device was simulated numerically. In order to find the flow field the experimental setup. and solving the equations Comsol 5 with laminar two- phase flow level-set method was used. In addition, flow References rate and pressure were controlled as initial condition to [1] Teh S, Lin R, Hung L, Lee A P, 2008 Lab Chip 8 198. [2] Zeng W, Jacobi I, Li S, Stone H, 2015 Journal of Micromechanics and attain the same size of droplet obtained in the Microengineering 25 115015. experiments. Then, monodispersity of the droplets was [3] Korczyk P M, Cybulski O, Makulskaa S and Garstecki P 2011 Lab Chip 11 173. analysed by calculating area of each droplet and [4] Basu A S 2013 Lab Chip 13 1892. comparing with experimental results [4].
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0102
Graphene/Pt nanoparticles/nafion nanocomposite as a novel electrochemical sensor for voltammetric determination of aliskiren
A.K. Ates1*, E. Er1 and N. Erk1
1 Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University, Ankara-Turkey
*Presenter: [email protected]
1. Introduction designed for the sensing of ALS. For this purpose, GRP/PtNPs/NFN nanocomposite has been The renin-angiotensin-aldosterone system (RAAS) has fabricated as an electrochemical sensing long been recognized to play a significant role in material. GRP/PtNPs/NFN/GCE sensor exhibited hypertension pathophysiology. Certain agents that an outstanding analytical performance towards the modify the RAAS can control blood pressure and ALS due to its unique physical and chemical improve cardiovascular outcomes. Aliskiren (ALS) is properties of graphene and platinum nanoparticles. the first of a new class of antihypertensive agents The developed method was successfully applied to known as renin inhibitors. Renin inhibitors are the determination of ALS in human plasma with antihypertensive drugs that block the first step in the satisfactory recovery results. It is concluded that renin-angiotensin system. Their mechanism of action GRP/PtNPs/NFN/GCE could be promising differs from that of the angiotensin-converting enzyme alternative sensor for routine analysis of ALS in inhibitors and angiotensin-receptor antagonists, but like real samples. these drugs, renin inhibitors interrupt the negative feedback effects of angiotensin II on renin secretion [1- References 2]. The determination of ALS at low-level has a great importance especially in real samples. Herein, we P. Wal, A. Wal, A. Kai. R, A. Dixit, J Pharm presented a facile and effective electrochemical Bioallied Sci. 2011 Apr-Jun; 3(2): 189–193. nanosensor based on graphene/platinum J.W. Cheng, Clinical Therapeutics, 2008 nanoparticles/nafion (GRP/PtNPs/NFN) for the Jan;30(1):31-47. electrochemical sensing of ALS using adsorptive W.S. Hummers, R.E. Offeman, J. Am. Chem. Soc. stripping differential pulse voltammetry (AdsDPV). 80 (1958) 1339. T.Q. Xu, Q.L. Zhang, J.N. Zheng, et al., Electrochim. Acta 115(2014) 109–115. 2. Experimental Graphene/platinum nanoparticles (GRP/PtNPs) nanocomposite was produced from graphene oxide (GO) via one-step chemical reduction method [3-4]. For the fabrication of proposed sensor, GRP/PtNPs solution containing NFN (0.25%, v/v) was prepared to constitute the GRP/PtNPs/NFN nanocomposite. A certain amount of dispersed GRP/PtNPs/NFN solution was dropped onto a clean GCE surface to obtain the proposed modified electrode (GRE/PtNPs/NFN/GCE).
The electrochemical performance of ALS on GRP/PtNPs/NFN/GCE was investigated in detail by cyclic voltammetry (CV) and AdsDPV. An irreversible and well-defined oxidation peak approximately at 1100 mV was observed on GRP/PtNPs/NFN/GCE using AdsDPV. Under optimal conditions, GRP/PtNPs/NFN/GCE exhibits good sensitivity and selectivity in the detection of ALS. The linear concentration range for ALS was found to be 0.1-5.0 µM with a low detection limit.
3. Conclusion It is the first time that a novel and highly sensitive graphene-based electrochemical platform was 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0103
Graphene based hydrogen peroxide sensitive biosensor for glucose sensing
A.Öncül1*, S.Cete2 and A.Yasar2
1Institue of Natural Sciences, Gazi University, Ankara, Turkey 2 Department of Chemistry, Gazi University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction In our study glucose biosensor based on immobilization of GOD in Pt nanoparticles/graphene/NFN Graphene is a carbon allotrope formed with sp2 nanocomposite film is responsive to a low concentration hybridized carbon atoms arranged in a 2-dimensional of H O (~5µM) and two different linear determination structure. [1] Its physical properties, such as excellent 2 2 ranges of 10-5-10-4 M (shown in figure-1) and 10-3-10-1 carrier mobility (200.000 cm2V-1s-1 for single layer) [2] M are detected. and very large surface area (2630 m2g-1) [3] make it a very popular choice for various applications. According to literature values [7-10] our sensor has low Biosensors including glucose biosensors are becoming detection limit and long linear range among to other increasingly important due to their applications in studies. This properties shows us our sensor is good biological and chemical analyses, clinical detection, and candidates for biochemical applications. environmental monitoring. We design a sensitive electrochemical sensor for glucose based on a glassy carbon electrode that was modified with a nanocomposite containing graphene, platinum nanoparticles (Pt-NPs) and nafion. The significance of glucose in human metabolism is well known, as is the fact that the defects in glucose level lead to complications of diabetes. [4]
2. Materials and Methods
Figure 1 Concentration vs. Current between -5 -4 10 -10 M H2O2 +0.6V in pH 7.0 phosphate buffer High-quality graphene (GR) was produced by an effective chemical method using Hummers' method. [5] 4. References GR/NFN(Nafion) preparation, the NFN solution was [1] A. K. Geim and K. S. Novoselov, Nat. Mater., 2007, 6, added to obtain 0.25 (m/v) nafion concentration in the 183–191. GR solution. The quantification of glucose can be [2] K. I. Bolotin, K. J. Sikes, Z. Jiang, M. Klima, G. achieved via electrochemical detection of the Fudenberg,J. Hone, et al., Solid State Commun., 2008, 146, enzymatically unchained H2O2. The immobilization of 351–355. glucose oxidase (GOD) over Nafion-solubilized metal [3] Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts and nanoparticles dispersed graphene and electrode has been R. S. Ruoff, Adv. Mater., 2010, 22, 3906–3924. achieved by cross-linking with glutaraldehyde. The [4] Shankaran DR, Uehara N, Kato T. 2008. Biosensors and performances of the biosensor have been investigated Bioelectronics 18:721–728. by electrochemical method at an optimum potential of [5] W.S.Hummers, R.E.Offeman, J.am.Chem.Soc.80 (1958) 1339 +0.6V in pH 7.0 phosphate buffer. All the [6] R.B. Rakhi, K. Sethupathi, S. Ramaprabhu, J. Phys. Chem. electrochemical measurements were performed with a B 113 (2009) 3190–3194. conventional three-electrode system. [7] R. Ning, W.B. Lua, Y.W. Zhang, X.Y. Qin, Y.L. Luo, J.M. Hu, A.M. Asiri, A.O. Al-Youbi, X.P. Sun Electrochimica Acta, 3. Conclusions 60 (2012) [8] E. Jin, X.F. Lu, L.L. Cui, D.M. Chao, C. Wang There are many reports regarding the electro catalytic Electrochimica Acta, 55 (2010), p. 7230 activity of gold and platinum for the sensing [9] X.X. Liu, H. Zhu, X.R. Yang Talanta, 87 (2011), p. 243 applications of glucose. [6] [10] S. Woo, Y.R. Kim, T.D. Chung, Y. Piao, H. Kim Electrochimica Acta, 59 (2012), p. 509 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0104
Enantioselective Chiral N-doped Graphene Quantum Dots
Aslı İ. Doğan1*, Funda Çopur1, Erhan Zor2, Sabri Alpaydin3 and Haluk Bingol3
1 Institute of Science, Necmettin Erbakan University, Konya/Turkey 2 Department of Science Education, Necmettin Erbakan University, Konya/Turkey 3 Department of Chemistry Education, Necmettin Erbakan University, Konya/Turkey
*Presenter: [email protected]
Abstract N-GQDs conjugated with L-PA (L-PA@N-GQDs) Although the enantiomers of chiral molecules taking a shows a green photoluminescent (PL) at 505 nm, on the fundamental place in chemistry, biochemistry and contrary, D-PA@N-GQDs shows very week PL around pharmacology have identical chemical and physical 470 nm as can be seen in Figure 1. The corresponding properties, they may exhibit different reaction ability in PL spectra showing excitation and emission changes for stereochemical reactions [1]. Within this context, both materials are also given in Figure 1. enantiomeric recognition of chiral molecules by different chiral selector is becoming one of the most important fields in analytical chemistry especially for pharmaceutical industry, clinical analysis, food analysis and forensic analysis. The commercial analytical techniques for recognizing enantiomers are usually based on high performance liquid chromatography and capillary electro-chromatography. Due to the advantages such as the low-cost, detection limits etc., a number of studies and reviews have been published related to spectrofluorometric method which is one of the most preferred methods. In these studies, small organic molecules, macrocyclic compounds, metal complexes, polymers and nanomaterials have been used as sensors in the stereochemical reactions. With the advances in nanotechnology over the past two decades, nanomaterials have been used almost in all areas and an increasing attention is focused on chiral detection studies. Among them, graphene quantum dots (GQDs) are emerging as promising fluorescent materials for biological applications, owing to their unique properties, such as excellent biocompatibility and solubility in physiological conditions [3]. Herein, a novel route to prepare different types of light- emitting chiral nitrogen-doped GQDs (cN-GQDs) is Figure 1 Column chromatography for purification, demonstrated by a hydrothermal process between GQDs photographs under daylight and UV light, and and D-/L-PA as chiral precursors. The purified cN- excitation and emission spectra of cN-GQDs. GQDs with silica column showed different emission properties based on their stereochemical moiety. cN- We also explored the feasibility of fluorescent L- GQDs were synthesized in three steps. As the first step, PA@N-GQDs for the selective chiral recognition of graphene oxide (GO) was prepared by following the chiral amino acids. Among them, the different improved Hummers method. In the second step quenching behaviors were observed when cysteine regarding the conversion of GO to nitrogen-doped enantiomers were added into the aqueous solution of GQDs (N-GQDs), the further cutting and in situ doping fluorescent L-PA@N-GQDs. progress of GO was performed in DMF media using a We express our deep thanks to the Scientific and Teflon-lined autoclave at 200 °C for 4 h [4]. After Technological Research Council of Turkey (TÜBİTAK) cooling, filtering and centrifuging, in the last step, N- for financial support (215Z222). GQDs were converted to cN-GQDs by applying the second hydrothermal process at 180 °C for 24 h References between GQDs and D-/L-PA [5]. The freshly as- prepared cN-GQDs have been purified via silica column [1] Izake E.L., J. Pharm. Sci., 96 (2007), 1659–1676. chromatography (Fig. 2). The obtained cN-GQDs were [2] Suzuki N. et al., ACS Nano 10 (2016) 1744-1755. characterized by FT-IR, Raman, XPS and TEM. From [3] Li X.et al., Adv. Funct. Mater., 25(2015), 4929-47. the purified products via silica column chromatography, [4] Sun J. et al., Part. Part. Syst. Charact., 32 (2015), 434–440. [5] Wang T.et al., Sci. Reports, 9591 (2015), 1-9. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0105
Preparation and Characterization of Biopolymeric Microspheres for Medical Applications
A. Gülsu1*, H. Ayhan2 and F. Ayhan2
1 Department of Molecular Biology and Genetics, University of Muğla Sıtkı Koçman 2 Department of Chemistry, University of Muğla Sıtkı Koçman
*Presenter: [email protected]
Abstract Cellulosic polymers are widely applied in medicine and generally regarded as biocompatible. It has wide ranging applications, e.g. as separation medium, carrier system and as adsorbent in extracorporeal blood purification [1-7]. It has also found applications such as for scaffolds in tissue engineering, temporary skin substitute, haemostatic agent, postoperative adhesion barrier, and as a culture material for hepatocytes [8]. As a biopolymeric material, various forms of cellulose are generally recognized as safe. The aim of this work was to prepare and characterize cellulose microspheres with narrow size distribution preferentially in the use for Fig 2. SEM photograph of cellulose microsheres haemostatic agent, post-operative adhesion barrier, and drug delivery. References Polysaccharide based cellulose microspheres were [1] de Oliveira W, Glasser WG (1996b) Hydrogels from prepared and stabilized by water/organic phase polysaccharides. II. Beads with cellulose derivatives. J emulsion system in chitosan media. The influence of Appl Polym Sci 61:81–86 several parameters on the particle size distribution was [2] Kuga S (1980) New cellulose gel for assessed. Various processing and formulation chromatography. J Chromatogr 195:221–230 parameters such as stirring speed, volume of processing [3] Kaster JA, de Oliveira W, Glasser WG, Velander WH medium and evaporation temparature were optimized to (1993) Optimization of pressure-flow limits, strength, have narrow size distribution. intraparticle transport and dynamic capacity by hydrogel The optical micrographes and SEM images of solids content and bead size in cellulose biopolymeric microspheres were taken for the immunosorbents. J Chromatogr A 648:79–90 characterization studies after preparation. The prepared [4] Wolf B, Horsch W (1991) Herstellung, cellulose microspheres were white and spherical in Eigenschaften und Verwendung der Perlcellulose—eine shape, stable in nature, 2% chitosan concentration, 1400 U ¨ bersicht. Pharmazie 46:392–402 rpm stirring rate, 40oC solvent evaporation temperature [5] Wolf B, Schmitz W, Schneider H (1996) Composites were determined as optimal conditions. The size of bead cellulose and hydrophilic solubiliziers. Int J distribution of cellulose microsphere was 5% <2 µm, Pharm 139: 87–94 80% 3-5 µm, 10% 7-9 µm at these preparation [6] Pes ˇka J, S ˇtamberg J, Hradil J, Ilavsky ´ M (1976) conditions. Cellulose in bead form: properties related to chromatographic uses. J Chromatogr 125:455–469 [7] Volkert B, Wolf B, Fischer S, Li N, Lou C (2009) Applications of modified bead cellulose as a carrier of active ingredients. Macromol Symp 280:130–135 [8] Hoenich N (2006) Cellulose for medical applications.BioResources1(2):270-280
Fig 1. Optical micrograph of cellulose microsheres
3rd International Congress on Biosensors, 5-7 October 2016, Ankara
Poster Presentation – PP0107
Carbon Quantum Dots Embedded Nanopaper for Iodide Sensing
Aylin Arıcı1*, Erhan Zor2, Ahmet O Saf3, Sabri Alpaydin3 and Haluk Bingol3
1 Institute of Science, Necmettin Erbakan University, Konya/Turkey 2 Department of Science Education, Necmettin Erbakan University, Konya/Turkey 3 Department of Chemistry Education, Necmettin Erbakan University, Konya/Turkey
*Presenter: [email protected]
1. Introduction Bacterial cellulose nanopaper was fabricated using Acetobacter xylinum bacteria in 50 g glucose, 5 g yeast Nanomaterial engineering technologies have the extract, 5 g (NH ) SO , 4 g KH PO and 0.1 g potential to revolutionize simple and disposable sensing 4 2 4 2 4 MgSO .7H O in 1 liters of water for two weeks at 28 ˚C systems. In this respect, paper-based (bio)sensors 4 2 [1]. Figure 2 shows SEM images of nanopaper at low provide new opportunities and directions in the and high magnifications. development of precise and sensitive analytical devices.
With the recent advances in flexible and transparent sensor (nano)technology, nanopaper-based sensors have attracted great attention of researchers [1]. Common paper is made of cellulose fibers with an average diameter of ~25 µm inducing significant light scattering that results in an opaque substrate. However, nanopaper is a transparent film due to the network-forming of nanocellulose fibers which are several micrometers long with a diameter below 100 nm. In addition, nanopaper is capable of adsorbing various kinds of ions, such as heavy metal ions or cationic dyes, via electrostatic interaction between functional groups and ions [2]. By Figure 2 SEM images of nanopaper incorporating nanoparticles/dots, nanopaper may exhibit selective detection of different kind of ions and may For sensing experiments, N-CQDs were embedded into give an analytical signal. Nanopaper-based platforms nanopaper by immersing in solution of N-CQDs. Then, has been scarcely used for optical (bio)sensing paper was dried in drying oven at room temperature. applications and even no published study exists for The resultant N-CQDs-embedded nanopaper was cut to carbon quantum dots embedded photoluminescent prepare desired disposable sensors and treated with the sensors to date. Hence, we sought to fabricate and test a sodium salts of anions (acetate, nitrate, sulfate, fluoride, simple and disposable nanopaper-based sensing chloride, bromide and iodide) by syringing on them. As platform for “yes/no” type detection of iodide (I-) anion. easily seen in Figure 3, the green luminescent of N- CQDs embedded transparent nanopaper was quenched 2. Experimental only in the presence of I- whereas no change was To prepare nitrogen doped carbon quantum dots (N- observed for the other tested anions which demonstrates CQDs), 0.5 g citric acid was firstly mixed with 55 mg that N-CQDs embedded nanopaper could be used as an HMDA. The mixture was heated to 240 ˚C using a effective disposable sensing platform for I- anion. teflon-lined autoclave. Subsequently, the color of the melting mixture changed from colorless to pale brown. The resultant N-CQDs solution was purified within the dialysis bag (MWCO: 2kDa) [3]. PL spectra of the purified N-CQDs showing excitation and emission changes were given in Figure 1.
Figure 3 Nanopaper treated with the sodium salts of the corresponding anions
References
[1] Morales-Narvàez et al., ACS Nano, 2015, 9 (7), 7296–7305 [2] Mautner et al., Environ. Sci.: Water Res. Technol., 2016, 2, 117–124. Figure 1 The excitation and emission spectra of N- [3] Liu et al., Nanoscale, 2013, 5, 1810–1815. CQDs.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0108
A High Performance Enzyme-Free Glucose Sensor Based on the Activated Carbon decorated Ni/Pd Nanocomposites
Fatih Şen1, Yağmur Koşkun1 and Aysun Savk1*
1Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupınar University, Kütahya, Turkey
*Presenter: [email protected]
Abstract Herein, an ultrasensitive and reliable non-enzymatic References electrochemical glucose sensor has been developed, [1] Wang L, Lu X, Ye Y, Sun L, Song Y (2013) Nickel- which is based on mesoporous Ni/Pd@AC cobalt nanostructures coated reduced graphene oxide nanoparticles prepared by a facile route aided by nanocomposite electrode for nonenzymatic glucose ultrasonication under mild conditions [1]. The biosensing. Electrochim Acta 114, 484–493. fabricated glucose sensor is capable of detecting glucose [2] A.A. Athawale, S.V. Bhagwat, P.P. Katre, (2006); with a wide linear region of 0.01–2 mM and an ultralow Nanocomposite of Pd-polyaniline as a selective detection limit of 10 µM. The Ni/Pd@AC methanol sensor, Sensors Actuators B Chem. 114 263– nanocomposite was characterized by transmission 267. electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) and UV– [3] Wang G, He X,Wang L, Gu A, Huang Y, Fang B, vis spectroscopy [2]. The nanoparticles have also Geng B, Zhang X (2013) Non-enzymatic electrochemical sensing of glucose. Microchim Acta exhibited favorable properties such as good selectivity, 180:161–186. reproducibility, durability and real sample analysis, which ensured its potential applications in the clinical diagnosis of diabetes [3].
Figure 1 . Cyclic voltammograms of NiPd/AC in 0.1 M NaOH of pH 7.0 at different scan rates: (a) 20; (b) 40; (c) 60; (d) 80; (e) 100; (f) 120; (g) 150; (h) 200 mV/s-1.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0111
Performance Enhancement of Micro-scale Microbial Fuel Cells (µMFC) for Nanoscale Power Generation
B. Şen Doğan1*, Nilüfer Erkal3, Ebru Özgür3, Özge Zorlu3 and H. Külah2, 3, 4
1 Department of Micro and Nanotechnology, METU, 2 Department of Electrical and Electronics Engineering, METU 3 Mikro Biyosistemler Inc., Ankara 4 METU-MEMS Research and Application Center, Ankara
*Presenter: [email protected]
1. Introduction µMFCs are small bioreactors converting the energy in the chemical bonds of organic matter into electrical energy through catalytic activity of microorganisms under anaerobic conditions. To obtain higher performance µMFCs, the internal resistance of µMFC can be decreased, the start-up time can be decreased or the biofilm formation quality can be increased. Biofilm is the complex structure adhering to surfaces that are regularly in contact with liquid substrate (organic matter) consisting of colonies of bacteria. 2. Design Figure 2 Effect of load on biofilm formation Optimization of chamber and/or cell geometries, chamber or electrode materials, and electrode surface characteristics is crucial to increase µMFC performance. Table 2 Comparison of performance values Thus, MEMS based µMFC electrodes are designed and 25 kΩ 10 kΩ Qian et al, fabricated. loaded loaded 2009 µMFC systems are operated under different loads or Bacteria S. S. S. open circuit with a Nafion 117 proton exchange Oneidensis Oneidensis Oneidensis membrane. Shewanella Oneidensis MR-1is preferred to MR-1 MR-1 MR-1 be the biocatalyst. Triptic Soy Broth is fed as anolyte (3 Anode area 0.61 cm2 0.61 cm2 0.15 cm2 µL/min) and 100 mM K3[Fe(CN)6] in phosphate buffer Anode volume 10.4 µL 10.4 µL 1.5 µL (5 µL/min) is fed as catholyte. With the design given in Anode/cathode Au/Au Au/Au Au/carbon Figure 1, the internal resistance is calculated as ~20 kΩ materials cloth under these conditions. Volumetric 133 µW/cm3 26 15 power density µW/cm3 µW/cm3 Volumetric 716 µA/cm3 500 670 current density µA/cm3 µA/cm3 Areal power 2 µW/cm2 0.4 0.15 density µW/cm2 µW/cm2 Areal current 12 µA/cm2 9 µA/cm2 6.7 density µA/cm2
4. Conclusions Acclimatization of µMFC under a load resulted in shorter start-up time. Power and current densities obtained is comparable to similar literature study. When the load is closer to internal resistance of the µMFC, Figure 1 Schematic of µMFC higher power and current densities are achieved.
3. Results References The start-up time of the biofilm formation and the effect [1] F. Qian, M. Baum, Q. Gu, and D. E. Morse, “A 1.5 of different loads are investigated. µL microbial fuel cell for on-chip bioelectricity generation,” Lab Chip, vol. 9, no. 21, p. 3076, 2009.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0112
Detection of FV Leiden Mutation with Electrochemical DNA Biosensor without Indicator
Berrin Tuğrul1*
1Molecular Biology Department, Biology Division, Faculty of Science and Letter, Manisa Celal Bayar University. Manisa, Turkey
*Presenter: [email protected]
1. Aim Keywords: Differential Pulse Voltametry, The method based upon detecting the hybridization Electrochemical DNA biosensor, FV Leiden, RFLP between probe and target sequences without indicator according to Guanin oxidation signalling in DNA is defined as identification with electrochemical DNA biosensor without indicator. This study aimed at detecting the G → A change in the 1691th nucleotide of FV gene (FV Leiden) by electrochemical DNA biosensor without indicator.
2. Material and Method
In this study, PCR products of 224 bp amplified from Figure 1. The results of RFLP obtained from PCR FV gene were used. Of 40 PCR products detected by products. 1. pUC19 DNA/MspI (HpaII) Marker, 23, 2. Restriction Fragment Lenght Polymorphism (RFLP) PCR product of 224bp., 3. RFLP Product of method , 20 were heterozygous, 5 homozygous and 20 homozygous genotype 4, 9. RFLP product of wild type (Figure 1). Synthetitic oligonucleotides, heterozygous genotype 5, 6, 7, 8. RFLP products of wild random sequence (21 mer belong to HBV), PCR type genotype products diluated in the ratio of 1/40 and denaturated were hybrydized with carbon paste electrode (CPE) to whose surface 23 mer probe (wild / mutant) was attached. Results of hybridization were measured in differential pulse voltammetry (DPV) between 0.75V and 1.4V range The consistency of the obtained results was evaluated statistically by Kappa (к) Methods.
3. Results The results of Guanin signalling obtained through the hybridization between the wild type probe with inosine Figure 2. Differential pulse voltammograms (A1) and and target sequences were found as 75-80 nA for wild histogram (A2) the results of Guanin signalling type persons, 20-25 nA for heterozygous persons, and obtained through the hybridization between the wild type probe with inosine and target sequences no signalling for homozygous persons (Figure 2). The results of Guanin signalling obtained through the hybridization between mutant probe with inosine and target sequences were determined as no signalling, 20- 25 nA and, 75-80 nA, for wild type, heterozygous and homozygous persons, respectively (Figure 3). When compared statistically, the results of electrochemical DNA biosensor and RFLP were found to be compatible with each other (kappa (ĸ)=1). 4. Conclusion Figure 3. Differential pulse voltammograms (A1) and histogram (A2) the results of Guanin signalling FV Leiden mutation, by using electrochemical DNA obtained through the hybridization between mutant biosensor without indicator, could be detected as probe with inosine and target sequences heterozygous and homozygous according to different Guanin signalling. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0113
Pt-Co nanoparticles decorated reduced graphene oxide for ultrasensitive dopamine, ascorbic and uric acid detection
Fatih Sen1, Sait Bozkurt1 and Betül Sen1*
1Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupinar University, Kütahya, Turkey
*Presenter: [email protected]
Abstract References Graphene is chemically synthesized by Hummers [1] F. Gonan, M. Buda, R. Cespuglio, M. Jouvet, J.-F. method reduction of colloidal dispersions of graphite Pujol, In vivo electrochemical detection of catechols in oxide [1-2]. Electrochemical characterization of the neostriatum of anaesthetized rats: dopamine or graphene modified Pt-Co (rGO/Pt-Co) is carried out by DOPAC Nature 286 (1980) 902–904. cyclic voltammetry (CV). The behavior of rGO/Pt- Co/GCE towards ascorbic acid (AA), dopamine (DA) [2] P. Ramesh, G.S. Suresh, S. Sampath, Selective and uric acid (UA) has been investigated by CV, determination of dopamine using unmodified, exfoliated differential pulse voltammetry (DPV) and graphite electrodes, J. Electroanal. Chem. 561 (2004) chronoamperommetry (CA). The rGO/Pt-Co/GCE is 173–180. successfully used for the simultaneous detection of AA,
DA and UA in their ternary mixture and DA in serum and pharmaceutical samples. The excellent electrocatalytic behavior of rGO/Pt-Co/GGE may lead to new applications in electrochemical analysis [1-2].
360,0µ DA
300,0µ F
240,0µ
AA 180,0µ I/A A 120,0µ
60,0µ UA
0,0 -0,2 0,0 0,2 0,4 0,6 0,8 E/V Figure: DPV results of AA, DA and UA at GCE, rGO/Pt-Co modified electrodes.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0114
A novel sensitive electrochemical sensor based on reduced graphene oxide decorated Pt nanocomposites for simultaneous determination of uric acid (UA)
Fatih Sen1, Ceyda Ulutürk1 and Betul Sen1*
1Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupinar University, Kütahya, Turkey
*Presenter: [email protected]
Abstract References In this paper, Pt -reduced graphene oxide–ZnO (Pt- [1] Sun, Z.; Fu, H.; Deng, L.; Wang, J.: Redox-active ZnO/rGO) nanoparticle composites was prepared by thioninegraphene oxide hybrid nanosheet: one-pot, simple and effective chemical routes. The synthesized rapid synthesis, and application as a sensing platform Pt-ZnO/rGO nanoparticle composite has been for uric acid. Anal. Chim.Acta 761, 84–91 (2013). successfully applied for glassy carbon electrode (GCE) doi:10.1016/j.aca.2012.11.057 surface modification[1]. The Pt-ZnO/rGO nanoparticle - [2]Yang,L.,Liu,D.,Huang,J.S.,You,T.Y.,2014.Sens.Actua modified GCE was applied for sensitive and selective torsB:Chem.193,166–172. determination of uric acid (UA) [2]. The biosensor [3] Y.F. Zhao, Y.Q. Gao, D.P. Zhan, H. Liu, Q. Zhao, Y. exhibited a linear dependence on UA concentration Kou, Y.H. Shao, M.X. Li, Q.K. Zhuang, Z.W. Zhu ranging from 10 to 750 μM with a detection limit of Talanta, 66 (2005), pp. 51–57 0.510 μM (S/N=3). The proposed UA sensor also [4] C.F. Tang, S.A. Kumar, S.M. Chen Anal. Biochem., showed an excellent stability, reproducibility and anti- 380 (2008), pp. 174–183 interference property[3-4].
Figure 1 Cyclic voltammograms of the Pt-ZnO/rGO - modified GCE at scan rate of 20–200mVs−1 in 0.1 M PBS containing 1mM UA[4].
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0115
Radiation Synthesis of Superadsorbent Conducting Smart Polymer/Pumice Nanocomposite Hydrogels
B. Taşdelen1*
1Department of Biomedical Engineering, Namık Kemal University, No:13 59860 Çorlu, Tekirdağ
*Presenter: [email protected]
Abstract inner diameter. All irradiations were carried out under Stimuli-responsive hydrogels with decent electrical irradiation in air at dose of 48 kGy at ambient properties are a promising class of polymeric materials temperature. Small discs of dry (ca. 0.1 g) of For a range of technological applications, such as crosslinked PNIPAAm (homopolymer or copolymer electrical, electrochemical and biomedical devices ction with IA) hydrogel were immersed in monomer solution Smart hydrogels which are sensitive to external stimuli of aniline (AN) in aqueous solution of 1 M HCl (3 mL), such as temperature, pH, electric field, magnetic force, until all the solution was absorbed into the hydrogel etc. could react actively to environmental changes, thus (taking 3 hour at least). These solutions were transferred receiving increasing attention in recent years [1]. to small glass tubes of 5 mm in diameter and irradiated However, traditional smart hydrogels are generally at dose of 48 kGy in air at ambient temperature under nonconductive while conductive gels hold great promise irradiation. for a wide range of applications in sensors, fuels cells, In this work, we study the synthesis of NIPAAm based supercapacitors, dye-sensitized solar cells and lithium hydrogels semi-interpenetrated with polyanilines and batteries [2]. Polyaniline (PANI) is a well-known the effect of copolymerization with IA and semi- conducting polymer, discovered in the late 19th century interpenetration on swelling capacity. We propose a and still under investigation due to the excellent novel alternative method to incorporate a conductive compromise between favorable properties and cost [4]. linear polymer (PANI) inside a network of pH-sensitive Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels are hydrogel under γ-irradiation at room temperature. In our typical thermosensitive materials. They change their study, poly(NIPAAm/IA) three dimensional network is volume abruptly and significantly on temperature formed after the first radiation induced polymerization. variations from external environments and exhibit a Since aniline monomer inside of PNIPAAm network, lower critical solution temperature (LCST) at about the polyaniline chain is formed inside of the 33°C [3]. Due to their unique properties, PNIPAAm polyacrylamide network during the second hydrogels found their applications in chemical devices, polymerization. The composite hydrogels with good tissue engineering, separation, microfluidic actuators, conductive properties also displayed unique pH and biomedical fields. Radiation induced in-situ temperature sensitivity. Significantly, the present polymerization and crosslinking, which can be carried findings have tested by embedding a conductive out at room temperature without initiators and catalysts polymer with a unique morphology via in situ radiation are safe, clean and effective method for the synthesis of grafted induced polymerization rather than the usual the hydrogels Use of pumice for removal of pollutants blending method would help in the design of drug by various treatment technologies, mainly adsorption delivery systems based on pH and temperature-sensitive has become popular during last decade. Turkey has and conductive polymers in biologic media. quite significant potential with respect to pumice reserves. In this work, semi-IPN poly(acrylamide-co- maleic acid)/polyaniline composite hydrogel was successfully synthesized by two-steps gamma radiation induced polymerization in aqueous solution. First, NIPAAm /itaconic acid (IA) copolymeric hydrogels were prepared by irradiation of the ternary mixtures of NIPAAm/IA/water in the presence of pumice by γ-rays at ambient temperature. Poly(NIPAAm-co-IA)/PANI hydrogels possessed a high electrical conductivity. Figure 1. Schematic representation of s-IPN NIPAAm/IA hydrogels were prepared by using gamma poly(NIPAAm-co-IA)/PANI hydrogels. rays irradiation copolymerization of NIPAAm monomer with addition of an anionic comonomer, namely IA. To prepare highly swollen NIPAAm/IA hydrogel systems, References NIPAAm weighing 10 g was dissolved in 100 mL water [1] D. Li, X. Zhang, J. Yao, G.P. Simon, H.Wang, Chem. in the presence of pumice. Then, 120 mg of IA were Commun. 2011, 47, 1710. added to each NIPAAm solution. Monomer solutions [2] L. Qiu, D.Liu, Y. Wang, C. Cheng, K.Zhou, Adv. Mater, 2014, 26, 3333. thus prepared were placed in a glass tube with 5 mm [3] Y. Hirokawa, T. Tanaka, J Chem Phys 1984, 81, 6379. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0251
Protein Adsorption on SAM Modified SiO2 Surfaces
B. Garipcan1*, and D. Hür2, L. Uzun3, F. Kuralay4 and S. Eren1
1 Institute of Biomedical Engineering, Boğaziçi University, 2 Department of Chemistry, Anadolu University, 3Department of Physics, Chemistry, and Biology, Linköping University 4Department of Chemistry, Ordu University
*Presenter: [email protected]
5. Introduction According to results of the protein adsorption study, fibrinogen has shown the highest affinity to Leu-SAM. Protein adsorption is one of the important issues that In addition, Leu-SAM has highest affinity for all can help to understand cell-surface interaction proteins than His-SAM. Albumin and IgG have higher mechanisms. As the matter of fact that, protein affinity to Leu-Silane than His-Silane. adsorption is as a precursor of cell-surface interaction and plays a significant role to indicate biocompatibility of a biomaterial [1,2]. In this study, novel amino acid (conjugated histidine, leucine) conjugated self- assembled molecules (SAMs) were synthesized and used to modify SiO2 surfaces to investigate protein adsorption.
6. Materials and Methods Novel amino acid (histidine, leucine) conjugated SAMs were synthesized in our laboratory, which have special affinity to SiO2 surfaces and attracted by chemisorption [4]. Syntheses of amino acid conjugated SAMs were characterized with H1 - Nuclear Magnetic Resonance (1H-NMR) Spectroscopy.
SiO2 surfaces were modified 3-(trimethoxysilyl)propane functional groups conjugated amino acids for (histidine and leucine), respectively. Substrates were modified in- situ in flow cell during QCM (SRS, CA, USA) frequency measurement. 10mM SAM solutions were used for modifications.
Modified SiO2 surfaces were characterized by water contact angle measurements and XPS analysis.
It is aimed to manipulate and change the adsorption of Figure 1. Fibrinogen adsorption results of 10mM His-Silane proteins (Albumin, Fibrinogen and Immunoglobulin G) and Leu Silane modified SiO2 surfaces. Δ frequency results (Hz) on the surfaces using amino acid conjugated SAMs. in PBS: 7.4 at RT. Protein adsorption was investigated in-situ by using Quartz Crystal Microbalance biosensors. According to results, target proteins have shown different affinity to 8. References amino acid conjugated SiO2 coated crystals depending [1] C. Fornaguera, G. Caldero, M. Mitjans M.P. Vinardell, C. Solans, the type of the amino acids and concentration. C. Vauthier, ”Interactions of PLGA nanoparticles with blood components: protein adsorption, coagulation, activation of the complement system and hemolysis studies” Nanoscale, 7, 6045-58, 7. Results and Discussions 2015 [2] Yang, D., X. Lu, Y. Hong, T. Xi, and D. Zhang, “The molecular In this study, aim of protein adsorption investigation mechanism of mediation of adsorbed serum proteins to endothelial part was manipulation of the protein adsorption by cells adhesion and growth on biomaterials,” Biomaterials, Vol. 34, pp. surface modifications. The surface modifications were 5747–5758, 2013. proved by QCM frequency measurement, water contact [3] C.K. Akkan, D. Hür, L. Uzun, B. Garipcan, “Amino Acid angle measurement, and XPS analysis before protein Conjugated Self Assembling Molecules for Enhancing Surface Wettability of Fiber Laser Treated Titanium Surfaces”, Applied adsorption investigations. Surface Science, 366,
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0117
A sensitive immunosensor based on indium tin oxide electrodes modified with carbonyldiimidazole and silane for determination of TNF-α
Burcu Özcan1* and Mustafa Kemal Sezgintürk2
1 Namik Kemal University, Faculty of Arts and Science, Chemistry Department, Biochemistry Division, Tekirdag, Turkey
*Presenter: [email protected]
1. Introduction Acknowledgement: This study was supported by The Tumor necrosis factor α (TNF-α) is a recognized marker Scientific and Technological Research Council of of the obesity-related inflammatory state [1], and DNA Turkey (TUBİTAK) by the project number of 113 Z methylation pattern of its promoter in blood cells is able 678. to predict the response to a hypocaloric treatment in humans [2]. TNF-α increases the expression of adhesion 3. References molecules on the endothelium and smooth muscle cells as has been shown in isolated animal and human [1]Odrowaz-Sypniewska G. (2007) Markers of vascular cells [3], and these molecules also impair the proinflammatory and pro-thrombotic state in the insulin signaling cascade. TNF-α also suppresses insulin diagnosis of metabolic syndrome. Adv Med Sci. signal transduction and expression of the insulin 52:246–250 receptor in isolated adipocytes, which leads indirectly to [2] Campion J, Milagro FI, Martinez JA (2009) glucose dysregulation and hyperglycemia, and eventual Individuality and epigenetics in obesity. Obes Rev pancreatic β-cell destruction. TNF-α is also associated 10:383–392. with CAD, infarction, stroke, thrombosis and peripheral [3] Lyon CJ, Law RE, Hsueh WA. Minireview: arterial disease [4]. Silane coupling agents containing adiposity, inflammation, and atherogenesis. carboxylate groups may be used to functionalize a Endocrinology 2003; 144: 2195–2200. surface with carboxylic acids for subsequent [4]Weyer C, Yudkin JS, Stehouwer CD, Schalkwijk conjugation with amine containing molecules. CG, Pratley RE, Tataranni PA. Humoral markers of Carboxyethylsilanetriol contains an acetate organo inflammation and endothelial dysfunction in relation group on a silanetriol inorganic reactive end. The to adiposity and in vivo insulin action in Pima silanetriol component is reactive immediately with Indians. Atherosclerosis 2002; 161: 233–242. inorganic –OH substrates without prior hydolysis of [5]Greg T. Hermanson, Functional Silane Compounds. alkoxy groups, as in the case with most other Bioconjugate Techniques. Third edition. 2013. silanization reagents. Carboxyethylsilanetriol has been used to add carboxylate groups to fluorescent silica nanoparticles to couple antibodies for multiplexed bacteria monitoring [5]. 2. Results and Discussion
In this study, a biosensor based on ITO (indium tin oxide) electrode was designed to determine TNF-α. Firstly, ITO electrodes were modified with NH4OH/ H2O2/H2O to obtain the OH groups on the surface. Later, the surface of ITO electrodes were treated with carboxyethylsilanetriol. After SAM formation, 1,1’- carbonyl diimidazol was used to interact with carboxyl groups in carboxyethylsilanetriol solution. Anti- TNF-α was covalently immobilized on modified ITO electrodes. Optimization steps are very important and necessary to construct a good, stable, repeatable and reproducible biosensor. For this purpose, all parameters such as SAMs concentration, 1,1’ carbonyl dimidazol concentration and incubation time, anti-TNF-α concentration and incubation time were optimized. For determining the immobilization steps and optimization of the biosensor, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0118
Label-free electrochemical immunosensor based on indium tin oxide as a electrode material for detection of tumor necrosis factor-
Burçak Demirbakan1* and Mustafa Kemal Sezgintürk2
1 Namik Kemal University, Faculty of Arts and Science, Chemistry Department, 2 Biochemistry Division ,Tekirdag, Turkey
*Presenter: [email protected]
1. Introduction characterize the immobilization of anti- TNF- process Pro-inflammatory cytokine tumor necrosis factor alpha and to determine TNF-. Analytical characteristics such as square wave voltammetry, linear determination (TNF-) is a 157-amino acid long polypeptide with an range, repeatibility, reproducibilty and regeneration of apparent molecular weight of 51 kDa when exists as a biosensors were determined. For expounding binding trimer [1,2]. It mediates a variety of cell functions, including the stimulation of nitric oxide (NO) characterization of TNF- and anti- TNF- single production which has been related to oxidative stress frequency impedance method was utilized. Scanning and diseases such as stroke, diabetes, severe electron microscopy was used for identifying the meningococcemia, rheumatoid arthritis, and chronic surface morphology and Kramers-Kronig transform was implemented on impedance datum. The biosensor has inflammation [3–4]. Research has shown that TNF- is exhibited good repeatability and reproducibility. Linear not produced by normal cells, but rather to be induced range of developed biosensor was 0.03 pg – 3 pg/mL. by invasive stimuli in the setting of both endoplastic and To verify the availability of the biosensor, the human infectious disease. Therefore, the development of serum samples were experienced. sensitive methods for detection of TNF- is particularly important for biomedical research and clinical Acknowledgement: Authors are thankful The Scientific diagnosis. Aldehyde (CHO) functionalities have been and Technological Research Council of Turkey utilized as supports for protein immobilization via (TUBİTAK) by the project number of 113 Z 678. electrostatic and covalent interactions, respectively. The use of aldehyde termini has the advantage of forming strong covalent bonds with the primary amines in the References protein residues [5]. 2. Result and Discussion [1] F. Bettazzi, L. Enayati, I.C. Sanchez, R. Motaghed, M. Mascini, I. Palchetti, Electrochemical bioassay for In this study, we designed a novel biosensor to detect the detection of TNF-alpha using magnetic beads and TNF- biomarker constructed on modified indium tin disposable screen-printed array of electrodes, oxide (ITO) disposable electrodes. Anti- TNF- was Bioanalysis 5 (2013) 11–19. immobilized through covalent 11-(triethoxysilyl) [2] Y. Liu, W. Zhang, X. Yu, H.W. Zhang, R. Zhao, D. undecanal which formed a self-assembled monolayers Shangguan, Y. Li, B.F. Shen, G.Q. Liu, Quartz crystal (SAMs) on modified ITO electrodes. Analytical biosensor for real-time kinetic analysis of interaction characteristics such as square wave voltammetry, linear between human TNF-alpha and monoclonal antibodies, determination range, repeatibility, reproducibilty and Sens. Actuators B Chem. 99 (2004) 416–424. regeneration of biosensors were determined. All [3] Y. Liu, Q. Zhou, A. Revzin, An aptasensor for characterization steps were monitored by Cyclic electrochemical detection of tumor necrosis factor in Voltammetry (CV), and Electrochemical Impedance human blood, Analyst 138 (2013) 4321–4326 Spectroscopy (EIS) techniques. To achieve reproducible [4] R. Say, S.E. Diltemiz, S. Celik, A. Ersoz, Nanolabel and repeatable biosensor system, all parameters such as for TNF-alpha determination, Appl. Surf. Sci. 275 SAMs concentration, antibody concentration and (2013) 233–238. antibody incubation time were optimized. The presented [5]. A. Riposan, Y. Li, Y. H. Tan, G. Galli, G. Liu, biosensor has wide determination range (5 fg-75 Structural Charactrerization of Aldehyde-Terminated fg/mL). Self-Assembled Monolayers, Department of Chemistry 111 (2007) 12727-12739. This study illustrates development of the biosensor for the determination of tumor necrosis factor alpha (TNF- ). For this purpose, firstly the biosensor was based on indium tin oxide (ITO) disposable electrodes modified with 11-(triethoxysilyl) undecanal. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods were applied to 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0119
Preparation and Enzymatic Application of a Time Dependent Growth of flower-like hybrid nanoflowers by horseradish peroxidase
Cevahir Altinkaynak1,2*, Melike Vecihe Koc1, Nalan Özdemir3 and Ismail Ocsoy1,2
1 Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey 2 Nanotechnology Research Center, Erciyes University, Kayseri, 38039 Turkey 3 Department of Chemistry, Faculty of Science, Erciyes University, Kayseri, 38039 Turkey
*Presenter: [email protected] 1. Introduction 3. Results and Discussion Enzymes which catalyze reactions with high specificity SEM images of synthesized hNFs were given in Fig.2. and very high rapidity are biocatalysts. Free forms of Encapsulation yields of hybrid nanostructures were enzymes have a short life time and this situation limites calculated by determining HRP concentration in the applications of enzymes in many areas. In order to supernatant (Table 1). increase the stability, catalytic activity and reusability of enzymes, many different immobilization methods are Table 1. The encapsulation yield of HRP hybrid used for this purpose. Recently, nanoflowers has gained nanostructures attention because the organic-inorganic hybrid Protein Concentration Different (mg/ml) Encapsulation nanostructures present higher stability and activity incubation time Initial After Yield (%) compared to free forms [1]. In this study, time incubation dependent growth of flower-like hybrid nanoflowers (hNFs) were observed using HRP (Horseradish 1 h 0,0060 70 peroxidase) enzyme as the organic portion and 3 h 0,0052 74
CuSO4.5H2O as inorganic components. Then some characteristics of these synthesized nanostructures were 6 h 0,02 0,0042 79 determined. To prove formation of mechanism, we have 12 h 0,0030 85 tested different incubation times. And the main controlling factors on the morphology were 24 h 0,0022 89 investigated. 48 h 0,0012 94 2. Experimental 72 h 0,0004 98 The hybrid nanoflowers were synthesized using a reported method [1,2,3] (Fig.1). First, CuSO4 stock solution was prepared in ultrapure water. Then, certain volume of that solution was added to PBS solution containing 0.02 mg mL-1 HRP. The resulting mixture was vigorously shaken for 30 seconds and incubated without disturbing at +4°C for 1, 3, 6, 12, 24, 48 and 72 hours. After incubation, the blue color precipitates were collected and washed by centrifugation at 4000 rpm for 15 minutes. The washing process was repeated at least 3 times. The collected precipitates were dried 50°C under vacuum. The structure of the synthesized hNFs was confirmed by FT-IR, XRD, and EDX. The enzymatic Figure 2 SEM images of the activities of hNFs and free horseradish peroxidase were nanostructures (A) 1h (B) 3h (C) determined by measuring colorimetric and 6h (D) 12h (E) 24h (F) 48h (G) spectroscopic methods using guaiacol as a substrate in 72h PBS buffer (pH 6.8). Most regular and uniform flower-shaped morphology was observed at a 72h incubation. The nanoflower exhibited the highest activity (120,39 EU/mg) compared the free HRP (33,48 EU/mg) and nanoflower formed in other incubation times. With these features, HRP has been used in different scientific and technical applications, such as removal of phenols from polluted water, and biosensor design. Figure 1 The growth mechanism of hybrid nanoflowers (A) nucleation and formation of primary crystals, (B) 4. References growth of crystals (C) formation of nanoflowers [1] J. Ge, J. Lei and R.N. Zare, Nature Nano. 2012, 7, 428–432. [2] B. Somtürk, M. Hançer, I. Ocsoy and N. Özdemir, 2015, Dalton Transactions [3] C. Altinkaynak, İ. Yilmaz, Z. Koksal, H. Özdemir, I. Ocsoy, N. Özdemir, International Journal of Biological Macromolecules, 84, 402-409 (2016).
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0120
Synthesis of Lipase Based Hybrid Nanoflower through the Coordination Chemistry and Their Excellent Activity
Cevahir Altinkaynak1,2*, Mehmet Yasar Dinler1, Nalan Özdemir3 and Ismail Ocsoy1,2
1 Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey 2 Nanotechnology Research Center, Erciyes University, Kayseri, 38039 Turkey 3 Department of Chemistry, Faculty of Science, Erciyes University, Kayseri, 38039 Turkey
*Presenter: [email protected]
1. Introduction 3. Results and Discussion As natural biocatalysts, enzymes have received Encapsulation yields of lipase hybrid nanostructures considerable attention owing to their unique properties, (0.1 mg mL-1) were calculated by determining lipase including high catalytic activity, stability, selectivity, concentration in the supernatant (Table 1). low toxicity and water-solubility. Accordingly, they have found widespread use in various scientific and Table 3 The encapsulation yield of lipase hybrid technical fields, including chemistry, biochemistry, nanostructures medicine, pharmaceutical science and industry [1-3]. However, the instability of the free enzymes in aqueous Type Encapsulation Yield (%) Lipase-Cu+2 93,11 solution strictly limits their applications. To address this +2 issue, two common methods, chemical modification and Lipase-Fe 81,63 Lipase-Zn+2 87,37 immobilization, have been used to enhance enzyme catalytic activity and stability. Recently, Zare and co- workers reported an elegant approach for the synthesis 400 of immobilized enzymes in the form of nanoflower with highly enhanced catalytic activity and stability [1]. 200 These flower-like hybrid nano structures are developed and used for various applications. 0 In this study, lipase hybrid nanostructures were prepared Lipase-Cu+2 Lipase-Fe+2 using different metal ions (Cu+2, Fe+2, Zn+2) and some Relavite Activity (%) characteristics of them were determined. They can be Lipase-Zn+2 commonly used as components in kits for medical applications and biosensors. 2. Experimental The morphology of the lipase hybrid nanostructures were demonstrated with SEM images in Fig. 2. The synthesis of nanostructures were accomplished using a described method before [1,3,4]. In this synthesis strategy, metal ions especially Cu2+ were rationally and successfully combined with lipase to form flower-like hybrid structures called “hybrid nanoflowers (hNF)”. The proposed mechanism of lipase-Cu+2 hNF formation is illustrated in Fig. 1. Figure 2 SEM images of the nanostructures (A) Lipase-Cu+2 (B) Lipase-Fe+2 and (C) Lipase-Zn+2
The activity of the immobilized enzyme was higher than the free enzyme. According to the free lipase enzyme; Lipase 221.90% Zn-Fe-lipase 175.61% and 128.27% Cu lipase showed greater of the activity. Figure 1 Schematic illustration of the preparation At the end of 8 measurements it was found to be reused of hybrid nanoflowers 60-80%. The structure of the synthesized lipase nanostructures were scanned via SEM and characterized by FT-IR, 4. References XRD, and EDX. [1] J. Ge, J. Lei and R.N. Zare, Nature Nano. 2012, 7, 428–432. [2] A. Atasever, H. Ozdemir, I. Gulcin, O. I. Kufrevioglu, Food Chem., 2013, 136, 864-870. The catalytic activity of synthesized lipase nano [3] B. Somturk, M. Hancer, I. Ocsoy and N. Özdemir, 2015, Dalton Transactions [4] C. Altinkaynak, I. Yilmaz, Z. Koksal, H. Özdemir, I. Ocsoy, N. Özdemir, International structures were evaluated by hydrolysis of olive oil and Journal of Biological Macromolecules, 84, 402-409 (2016). oleic acid concentration was measured.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0206
Synthesis of Catecholamine-Metal İons Coordinated Hybird Nanoflowers and Their Catalytic, Antioxidant and Antimicrobil Properties
Çağla Çelik1* and Ismail Ocsoy1
1Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey
*Presenter: [email protected]
Abstract Note: DA, E and NE represent dopamine and Herein we report the preparation of organic–inorganic epinephrine, norepinephrine, respectively nanoflowers formed of catecholamines and metal ions using a newly developed and an elegant immobilization 5. References approach. While copper (II)/iron (II) metal ions were [1] J. Ge, J. Lei, R.N. Zare, Protein–inorganic hybrid used as inorganic component, epinephrine, nanoflowers, Nat. Nanotechnol. 7 (2012) 428–432. norepinephrine and dopamine were utilized as the [2] Z. Wu, X. Li, F. Li, H. Yue, C. He, F. Xie, Z. Wang, organic component. We also demonstrated how Enantioselective transesterification of (R,S)-2-pentanol dopamine (DA) based hybrid nanoflowers (HNFs) acted catalyzed by a new flower-like nanobioreactor, RSC as catalytic, antioxidant and antimicrobial agents. The 2+ 2+ Adv. 4 (2014) 33998. catalytic performances of DA-Cu and Fe HNFs were [3] B. Somturk, M. Hancer, I. Ocsoy, N. Özdemir, evaluated as peroxidase-enzyme by oxidation of Synthesis of copper ion incorporated horseradish guaiacol (2-methoxyphenol) to 3,3-dimethoxy-4,4- peroxidase-based hybrid nanoflowers for enhanced diphenoquinone in the presence of hydrogen peroxide 2+ catalytic activity and stability, Dalton Trans. 44 (2015) (H2O2) based on Fenton-like reaction. DA-Fe HNFs exhibited antioxidant activity towards 2,2-diphenyl-1- 13845–13852. [4] I. Ocsoy, E. Dogru, S. Usta, A new generation of picrylhydrazyl (DPPH). Finally, we also used the DA- 2+ 2+ flowerlike horseradish peroxides as a nanobiocatalyst Cu and Fe HNFs as antimicrobial agent against for superior enzymatic activity, Enzyme Microbiol. bacterial pathogens (Gram+ bacteria Staphylococcus Technol. 75–76 (2015) 25–29. aureus and Gram- bacteria Escherichia coli) and fungal [5] B. Somturk, I. Yilmaz, C. Altinkaynak, A. Karatepe, pathogen (Candida albicans). We claim that HNFs N. Özdemir, I. Ocsoy, Synthesis of urease hybrid produced with this synthesis approach can be empolyed nanoflowers and their enhanced catalytic properties, in fabrication of biosensors and bioanalytical tools and Enzyme Microbiol. Technol. 86 (2016), 134–142. can be used in various scientific and technical fields. [6] C. Altinkaynak, I. Yilmaz, Z. Koksal, H. Özdemir, I.
Ocsoy, N. Özdemir, Preparation of lactoperoxidase incorporated hybrid nanoflower and its excellent activity and stability, Int. J. Biol. Macromol. 84 (2016) 402–409. [7] C. Altinkaynak, S. Tavlasogluc,, N. Özdemir, I. Ocsoy, A new generation approach in enzyme immobilization: Organic-inorganic hybrid nanoflowers with enhanced catalytic activity and stability, Enzyme Microbiol. Technol. 93 (2016) 105–112.
Figure 1. (1) Illustration of plausible formation mechanism of catecholamines–Metal2+ HNFs formed in typical three successive steps (nucleation, growth and completion). Potential uses ofthe HNFs as (2) catalytic, (3) antioxidant and (4) antimicrobial agents.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0122
“Label-free impedimetric aptasensor for Ochratoxin‑A detection using Iridium Oxide nanoparticles”
Lourdes Rivas1,2, Carmen C. Mayorga-Martinez1, Daniel Quesada-González1*, Alejandro Zamora-Gálvez1, Alfredo de la Escosura-Muñiz1 and Arben Merkoçi1,3
1ICN2- Nanobioelectronics & Biosensors Group, Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain 2Department de Quimica, Universitat Autonoma de Barcelona, 08193, Bellaterra (Barcelona), Spain 3ICREA- Institucio Catalan de Recerca i Estudis Avançatsi 08010 Barcelona, Spain
*Presenter: [email protected]
Abstract References:
Ochratoxin A (OTA) is a mycotoxin generated by 1. Food and Agricultural Organization (FAO). Manual different fungi species such as Aspergillus and on the application of the HACCP system in mycotoxin Penicillium during their growth. This toxin is a prevention and control; FAO: Rome, 2001; p 124. hazardous contaminant present in a great number of agricultural products such as cereals, coffee beans, dried 2. Rivas, L.; Mayorga-Martinez, C.; Quesada-González, fruits, cocoa, nuts, beer and wine, causing economic D.; Zamora-Gálvez, A.; de la Escosura-Muñiz, A.; losses to agricultural trade [1]. Different methods are Merkoçi, A. Anal. Chem. 2015, 87, 5167−5172. routinely used for analysis of mycotoxins, such as chromatography, enzyme-linked immunosorbent assay 3. Mayorga Martinez, C.; Pino, F.; Kurbanoglu, S.; (ELISA), and lateral flow assays (LFA), but label-free Rivas, L.; Ozkan, S.; Merkoçi, A. J. Mater. Chem. B and highly sensitive methods are still strongly required. 2014, 2, 2233−2239. In this context, we present here [2] a novel aptasensor for ochratoxin A (OTA) detection based on a screen- 4. Rivas, L.; de la Escosura-Muñiz, A.; Pons, J.; printed carbon electrode (SPCE) modified with Merkoçi, A. Electroanalysis 2014, 26, 1287−1294. polythionine (PTH) and iridium oxide nanoparticles (IrO2 NPs) [3, 4], which exhibit good stability, biocompatibility and catalytic properties. The electrotransducer surface is modified with an electropolymerized film of PTH followed by the assembly of IrO2 NPs on which the aminated aptamer selective to OTA is exchanged with the citrate ions surrounding IrO2 NPs via electrostatic interactions with the same surface. Electrochemical impedance −3/−4 spectroscopy (EIS) in the presence of the [Fe(CN)6] redox probe is employed to characterize each step in the aptasensor assay and also for label-free detection of OTA in a range between 0.01 and 100 nM, obtaining one of the lowest limits of detection reported so far for label-free impedimetric detection of OTA (14 pM; 5.65 ng/kg). The reported system also exhibits a high reproducibility, a good performance with a white wine sample, and an excellent specificity against another toxin present in such sample.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0121
Preparation of Carbon Paste Electrode containing Polyaniline-Activated Carbon Composite for Amperometric Detection of Phenol
Halit Arslan1, Derya Yücel 2, Bekir Sıtkı Çevrimli3, Hüseyin Zengin4, Demet Uzun1* and Fatma Arslan1
1Department of Chemistry, Faculty of Sciences, Gazi University, 06500, Ankara, Turkey 2 Department of Chemistry, Institute of Sciences, Gazi University, Ankara, Turkey 3Department of Chemical Technology, Ataturk Vocational College, University of Gazi, 06500 Ankara, Turkey, 4Department of Chemistry, Faculty of Arts and Sciences, Gaziantep University, Gaziantep, Turkey
*Presenter: [email protected]
Abstract
Carbon paste electrodes are widely used in electro analysis owing to their low background current, wide potential window, chemical inertness, simple, and fast preparation from inexpensive materials. [1]. A large variety of phenolic compounds exists. Some of them may have harmful effects for the health. Their accurate determination is of great importance due to their toxicity and persistency in the environment, and the detrimental effect of phenols on human health requires a strict directive for the identification and quantification of such compounds [2, 3]. In this study, a novel carbon paste electrode using the salt form of polyaniline (pani)- activated carbon composite sensitive to phenol, was prepared. Scheme 1 Reaction scheme for the detection of phenol
1. Materials and Methods References Polyphenol oxidase (tyrosinase) enzyme was [1] Arduini, F., Giorgio, F.Di., Amine, A., Cataldo, F., immobilized onto carbon paste electrode containing Moscone, D., and Palleschi, G. (2010). Electroanalytical polyaniline-activated carbon by cross-linking with Characterization Of Carbon Black Nanomaterial Paste glutaraldehyde. The amperometric determination is Electrode: Development Of Highly Sensitive Tyrosinase based on the electrochemical reduction of o-quinone Biosensor For Catechol Detection. Analytical Letters, generated in the enzymatic reaction of phenol at -0.15 V 43, 1688–1702. vs. Ag/AgCl. Scheme 1 shows reaction for the phenol [2] Hervás Pérez, J.P., Sánchez-Paniagua López, E., determination. López-Cabarcos, M., López-Ruiz, B. (2006) Amperometric tyrosinase biosensor based on 2. Results and Discussion polyacrylamide microgels. Biosensors and Bioelectronics, 22, 429–439. In this study, a novel carbon paste electrode using the [3] Rogers, K.R., Becker, J.Y., Wang, J., Lu, F., (1999). salt form of polyaniline (pani)-activated carbon Determination of phenols in environmentally relevant composite sensitive to phenol, was prepared. The effects matrices with the use of liquid chromatography with an of pH and temperature were investigated and optimum enzyme electrode detector. Field Anal. Chem. Technol., parameters were found to be 8.0 and 45 °C, 3(3), 161–169. respectively. The linear working range of the electrode was 1.0×10-6 - 5.0×10-5 M, R2 =0.982. The storage stability and operation stability of the enzyme electrode were also studied.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0126
Gold Modified Anisotropic Titanium Nanorod arrays for Sensing Applications
D.Ş. Özden1*, M. Yılmaz2, E. Pişkin1, G. Demirel3
1 Department of Bioengineering Chemical Engineering Department and Bioengineering Division, Center for Bioengineering and Biyomedtek/Nanobiyomedtek, Hacettepe University, 06800, Beytepe, Ankara, Turkey 2 Engineering and Architecture Faculty, Bioengineering Department, Sinop University, 57000, Sinop, Turkey 3 BIMREL Research Group, Department of Chemistry, Gazi University, Turkey
*Presenter: [email protected] 1. Introduction Nanostructured titanium has become of great importance in the development of functional materials which could be used in photocatalysis, sensing, photovoltaics, water splitting, lithium ion batteries and tissue engineering. Among the various oxide and non- oxide 3-D nanostructured materials, titanium nanorods (TiNRs) have also attracted increasing attention due to their unique features [1]. Here, we demonstrated a simple method to fabricate directional 3-D titanium nanorod arrays through an oblique angle vapor deposition approach. By combining fabricated TiNR arrays with a thin layer of gold, they were utilized in plasmonic catalysis and sensing applications.
2. Experimental
Figure 1. Top-view (a) and cross-sectional (b) SEM The glass slides or silicon wafers were first cut images of fabricated TiNRs and (c) cross-sectional (2.5x2.5 cm) and washed with deionized water, acetone, (d) top-view images of Au thin film coated TiNRs. and piranha solution consecutively. To eliminate any contaminants, pre-cleaned surfaces were then treated Gold deposition was performed in PVD as thin film with oxygen plasma at low pressure (0.2 mbar) for 30 with different thickness such as 10, 20, 30 nm. min before titanium deposition. The directional titanium Moreover, the effect of calcination of surface modified nanorod arrays were fabricated in a physical vapor titanium nanorods were examined by using different deposition (PVD) system (NANOVAK HV, Ankara, temperatures such as 300, 450, 500, 600, 750 °C [3]. Turkey) using a homemade OAD equipment. The Specifically, we studied the dewetting of gold films on thickness of deposited films was monitored using an TiNR arrays. To investigate the SERS activity, the Inficon XTM/2 deposition monitor with 0.5% raman enhancement properties were measured. sensitivity. Base pressure was gained by using a -3 As a result, we showed the formation of titanium mechanical pump (Edwards E2M2 model, up to 10 -6 nanorod structures with PVD-OAD technique. Our Torr) and a turbo pump (Turbovac 50, up to 10 Torr) results indicated that the SERS activity for gold and monitored via a Terranova Model 934 Wide Range deposited TiNRs can be manipulated through annealing Vacuum Gauge Controller. During deposition, the base -6 temperature. pressure was almost fixed at ~10 Torr with a titanium -1 Ackowledgement: This work was supported by Gazi evaporation rate of 0.1 Å s [2]. The directional titanum nanorods were created at different deposition angles to University (05/2015-19). manipulate their surface densities. References 2. Results and Discussion [1] Yu et al. Applied Catalysis B: Environmental, 2009, 90, 595–602. Figure 1 shows the top-view and cross-sectional SEM [2] Yılmaz et al. Phys. Chem. Chem. Phys., 2014, 16, images of fabricated TiNRs. It is clear that the TiNRs 5563. are uniform and vertically aligned to the glass surface. [3] Schaefer et al. Acta Materialia, 2013, 61, 7841–7848 The length of the fabricated TiNRs were analyzed by employing freeware ImageJ software and determined to be 1.92 ± 0.05 µm.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0210 Poster Presentation – PP0126
Removal of Toxic Metals by using Janus Micromotors
D. A. Uygun1,2*, B. Jurado-Sánchez1, M. Uygun1,2 and J. Wang1
1Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA 2Department of Chemistry, Adnan Menderes University, Aydın, Turkey
*Presenter: [email protected]
1. Introduction Heavy metal pollution has been accelerated dramatically since the industrial revolution, and is currently posing major environmental and human health concerns. Such widespread use has resulted in substantial accumulation of toxic heavy metals in the environment and living organisms. Therefore, the removal and detoxification of metals, such as lead, cadmium, thallium, mercury, and Figure 1 SEM images showing the Janus structure arsenic has attracted a considerable recent attention [1]. before (a) and after (b) dissolution of the Mg Advances in nanotechnology have opened new horizons core. for addressing metal remediation demands due to the Fig. 2 displays the effect of the treatment time upon the unique properties of nanosized materials, e.g., extremely motor induced removal of Z(II), C(II) and P(II). A high surface area, high catalytic and antimicrobial dramatic decreases of the initial response of these heavy properties and tunable surface chemistry.3 Recently developed meso-2,3-dimercaptosuccinic acid (DMSA)- metal ions (a), corresponding to 85% (Zn and Cd) to iron oxide nanoparticles display high capacity and 99% (for Pb) removal, is observed following a 3 min selectivity for softer heavy metals in water samples [2]. treatment with the Mg/Ti/Au/ DMSA micromotor (d). Here we describe high-speed metal chelation and Longer navigation times result in the complete removal removal using self-propelled ligand-functionalized of these metal ions from the contaminated samples (e). water-powered micromotors. The autonomous In contrast, no apparent change in the metal propulsion of synthetic micromotors through fluid environments is one of the most exciting fields of concentration is observed in the presence of the moving nanotechnology [3]. The new self-propelled chelation unmodified (ligand-free) micromotors. platforms described here are based on fuel-free Mg Janus-micromotors, functionalized with DMSA, for efficient removal of heavy metals from environmental and biological media
2. Methods The micromotors were prepared using magnesium microparticles as the base particles and one half of microparticles were coated with a 100 nm Ti layer and a 10 nm gold layer. External gold surface of microparticles was modified by overnight incubation of meso-2,3-dimercaptosuccinic acid.
Zn, Cd and Pb amounts were measured Figure 2 Effect of the navigation time on the electrochemically. For this, stripping voltammetric removal of Zn(II), Cd(II) and Pb(II) by measurements were performed with an “in situ” co- Mg/Ti/Au/DMSA micromotors. deposition of a bismuth film and the target metals in the presence of dissolved oxygen 4. References 3. Results [1] F. Fu and Q. Wang, J. Environ. Manage., 2011, 92, The new micromotors were prepared by half-coating 407. Mg microparticles (average diameter 20 μm) with Ti [2] W. Yantasee, C. L. Warner, T. Sabgvanich, R. S. and Au layers. The scanning electron microscopy Addleman,T. G. Carter, R. J. Wiacek, G. Fryxell, C. (SEM) images of Fig. 1, reveal the spherical Janus Timchalk and M. Warner, Environ. Sci. Technol., 2007, structure of the resulting micromotor, indicating that it 41, 5114. maintains its structure after the modification process. [3] J. Wang, Nanomachines: Fundamentals and Applications, Wiley-VCH, Weinheim, Germany, 2013, ISBN 978-3-527-33120-8. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0123
Reliability and sensitivity of paper-based glucose sensing: comparison of sensing mechanisms Deniz Baş1*
1 Nanobiosensing & Food Safety Research Group, Department of Food Engineering, Çankırı Karatekin University, Çankırı, 18100, Turkey
*Presenter: [email protected]
1. Introduction and 0.1 M 4-AA mixture was used as test solution. For visual detection; 2 µl of test solution was pipetted onto Paper-based sensing platforms are promising due to test zones and dried at room temperature. Glucose assay their low-cost and easy-to-use structure [1]. The sensing was performed by pipetting 2 µl of standard glucose principle mostly based on colorimetric read-out. Until a solutions to the test zones. Finally, quantitative glucose few years back, paper-based platforms/assays are only measurement was performed by the reading the L*a*b used for qualitative measurements. By implementing color space values and sensitivity of the mechanisms specific colorimetric reactions and the usage of was investigated. optoelectronic devices i.e. scanners, cell phones etc, paper-based platforms became important for 3. Results and Discussion quantitative sensing for point-of-care diagnostics. Herein, two glucose sensing mechanisms were Comparison of glucose sensing strategies: As a result of compared and reliability and sensitivity of the methods quionone dye formation mechanism, color development were investigated. is uniform when compared with iodine formation 2. Materials and Method reaction (Figure 1) and the color intensity is higher. Uniformity of color developed by quionone dye Preparation of sensing platform: Design of the patterns formation increases the reliability of glucose sensing was performed by opensource software Inkscape 0.91 and higher color intensity lowers the limit of detection. (www.inkscape.org). Patterns were printed on the filter papers (Sartorius Stedim, quantitative filter, particle retention 12-15 µm). Finally, hydrophobic channels were obtained by painting with permanent ink marker (Edding 141F).Glucose measurements: Glucose, glucose oxidase (GOx), peroxidase (POD), phenol, potassium iodide (KI), 4-aminoantipyrine (4-AA) were purchased from Sigma-Aldrich (Germany). Two different glucose sensing mechanisms (Hata! Başvuru Figure 1. Paper-based glucose sensing A) Quinone dye kaynağı bulunamadı. and Hata! Başvuru kaynağı formation B) iodine formation bulunamadı.) were used and for both mechanisms the specific reaction between glucose and glucose oxidase Limit of detection (LOD) values for glucose were enzyme is the common step. Mechanisms differ from determined as ~0.5 mM and ~1 mM for quinone and each other according to the reaction of hydrogen iodine formation, respectively. LOD for quinone peroxide with the chromagens. method on paper platform is also lower than the LOD value of same method performed by spectrophotometer. The stability of the quinone dye formation mechanism was investigated for about 40 days. For this purpose; test solution was pipetted onto test zones and paper
Scheme 1. Glucose assay based on iodine formation platforms were stored at room temperature by avoiding interaction with the ambient light. Test platform is stabile for 30 days. On the other hand, iodine method is not stabile and in almost 3 days, a drastic decrease had been observed. Moreover, results obtained by using scanner and cell phones (Android and iosX) were
investigated and performance of platforms were Scheme 2. Glucose assay based on the quinone dye determined. formation 4. References For iodine formation reaction, 300 U/ml GOx, 500 U/ml [1] A.W. Martinez, S.T. Phillips, M.J. Butte, G.M.Whitesides, Patterned POD and 0.6 M KI mixture and for quinone dye paper as a platform for inexpensive, low-volume, portable bioassays, formation 300 U/ml GOx, 500 U/ml POD, 1 M phenol Angew. Chem. Int. Ed. 46 (2007) 1318–1320. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0124
Electrochemical determination of interaction between DNA and anticancer drug capecitabine by using DNA modified carbon paste electrodes
D. Kiziloluk1*, G. Gökçe2, Ş. Çetinus1 and A. Erdem3
1Cumhuriyet University, Faculty of Science, Department of Biochemistry, Sivas, TURKEY 2Cumhuriyet University, Faculty of Education, Department of Elementary Science, Sivas, TURKEY 3Ege University, Faculty of Pharmacy, Department of Analytical Chemistry, Izmir, TURKEY
*Presenter: [email protected]
Abstract Recently there has been an increasing attention to detect Acknowledgements: This work is supported by the the interaction between DNA and anticancer drugs by Scientific Research Project Fund of Cumhuriyet using biosensor technologies 1. In this study, it was University under the project number F-387. investigated that the interaction between capecitabine which is anti cancer drug, and DNA by electrochemical References methods in combination with carbon paste electrode 1 Wang, L., Lin, L., Ye, B. (2006). Electrochemical (CPE). The interaction between capecitabine and the studies of the interaction of the anticancer herbal drug single stranded DNA (ssDNA) and double stranded emodin with DNA, Journal of Pharmaceutical and DNA (dsDNA) obtained from calf thymus (ct dsDNA) Biomedical Analysis, 42: 625–629. was investigated by monitoring the differences at the 2 Erdem, A., Özsöz, M., (2001). Interaction of guanine oxidation signals. The experimental parameters anticancer drug, Epirubicin with DNA, Analitica such as the concentrations of ct DNA and drug, and also Chimica Acta, 437, 107-114. the interaction time were optimized. The detection limit 3 Wang, J., Flechhsig, G., Erdem, A., Korbut, O., was estimated and the results were comprised Gründler, P. (2004). Label-free DNA Hybridization repeatability of carbon paste electrode. It was also based on coupling of a heated carbon paste electrode confirmed that ct DNA had immobilized onto electrode with magnetic separations, Electroanalysis, 16 (11), surfaces by impedimetric measurements using 928-931. electrochemical impedance spectroscopy technique 2, 4 Erdem, A., Özsöz, M. (2002). Review: 3. Electrochemical DNA biosensors based on DNA-Drug interactions, Electroanalysis, 14, 965-974. Ct dsDNA and ct ssDNA were immobilized onto the 5 Erdem, A., Özsöz, M. (2001) Voltammetry of the electrode surface, and accordingly the voltammograms anticancer drug mitoxantrone and DNA, Turkish were recorded. It was observed that there was an Journal Chemistry, 25: 469- 475. increase at the oxidation signal of guanine 4. 6 Palecek, E., Fojta, M., Jelen, F., Vetterl, V. (2002).
Electrochemical analysis of nükleic asids, the In the case of DNA interaction with capecitabine, there Encyclopedia of electrochemistry, Bioelectrochemistry, was a decrease at guanine signal. Thus, it could be 9: 365-429. explained as the result of interaction between DNA and capecitabine. It was tested that interaction between capecitabine and ct dsDNA or ct ssDNA separately using carbon paste electrode 5.
The calibration graphs were plotted between the concentration of capecitabine and guanine oxidation current in order to determine the detection limits. The detection limit (DL) was estimated of carbon paste electrode for ct ssDNA and ct dsDNA and found to be 17, 12 μg/mL and 17, 35 μg/mL respectively 6.
As a result, it is concluded that the proposed method could be used furtherly for elucidation of the interaction between the newly synthesized molecules and DNA.
Key Words: Electrochemical DNA Biosensor, Capecitabine, Carbon Paste Electrode, Differential Puls Voltammetry, Electrochemical Impedance Spectroscopy.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0125
A Highly Sensitive Nonenzymatic Ascorbic Acid Sensor Based on Quantum Dots and Graphene Oxide
D. Söğüt1*, Z.Ö. Erdoğan1, C.Başlak1 and S. Küçükkolbaşı1
1Department of Chemistry, Faculty of Science, Selçuk University, 42075 Konya, Turkey
*Presenter: [email protected]
Abstract Ascorbic acid (AA), water soluble vitamin, plays important role in several life processes, such as antioxidant, nutritional factors. AA is commonly used in food, beverages, pharmaceutical and cosmetic [1]. The detection of AA is important in food industry and diagnostic application. Many methods have been used for detection of AA, including spectroscopy, titrimetry, enzymatic analysis, HPLC, electrophoresis and electrochemical methods. Among these methods, electrochemical method is very interesting because of their high sensitivity, ease of monitoring, simplicity and Figure 1. Amperometric response of low cost [2]. CdTe/GO/GCE. Because of their unique chemical, physical and electronic properties, Quantum dots (QDs) and graphen oxide (GO) are now extremely attractive and important References nanomaterials in analytical applications [3]. In this work, CdTe QDs with the size of about 3 nm were [1] Liu, J.J., Chen, Z.T., Tang, D.S., Wang, Y.B., prepared and a novel electrochemical sensing platform Kang, . L.T., Yao, J. N., Sensors and Actuators B, of ascorbic acid on CdTe/GO electrode was explored. In 212 (2015) 214-219. this study, a novel, stable and sensitive non-enzymatic AA sensor was constructed based on a glassy carbon [2] Liu, B., Luo, L., Ding, Y., Si, X., Wei, Y., Ouyang, electrode (GC) modified with quantum dots supported X., Xu, D., Electrochimica Acta, 142 8 (2014) 336- on graphene oxide (QDs -GO). 342
The electrochemical performance of the modified [3] Zhao, J., Chen G., Zhu L., Li G., Electrochemistry electrode for detection of AA was investigated by cyclic Communications, 13 (2011) 31–33. voltammetry and amperometric measurements. Electrochemical properties of different materials on the electrode surface was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements in 0.10 M KCl solution containing 50 mM Fe(CN)6 3−/4− as a redox probe. The effect of pH, buffer concentration, deposition potential, deposition time and scan rate were investigated for modified electrode.
Compared to a bare GC the modified electrode exhibited a rapid response to AA and the amperometric signal showed a good linear correlation to AA concentration in a broad range from 32.5-500 µM with a correlation coefficient of R = 0.9991. Moreover, the proposed sensor was applied to the determination of AA in in fresh fruit juice samples. The satisfactory results obtained indicated that the proposed sensor was promising for the development of novel electrochemical sensing for AA determination.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0128
Application of SWCNT and poly(3-methylthiophene) modified sensors for simultaneous determination of levodopa and benserazide
Ebru Kuyumcu Savan1* and Gamze Erdoğdu2
1Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, İnönü University, Malatya, Turkey 2Department of Chemistry, Faculty of Science, İnönü University, Malatya, Turkey
*Presenter: [email protected]
1. Introduction dried at room temperature for 1 day. Levedopa (L-Dopa) and Benserazide are a significant 3. Results and Discussion neurotransmitters because of its role in the functioning of the cardiovascular, renal and central nervous system. Determination of Levedopa and Benserazide It is important to detect L-Dopa and Benserazide using a reliable method with good sensitivity and selectivity. Due to the electrochemically oxidizable characteristic, there has long been a great deal of developments in electrochemical determination of L-Dopa and Benserazide [1-3]. The coexistence of L-Dopa and Benserazide and other reductants such as ascorbic acid with very close oxidation potentials leads to interference in voltammetric response. The anodic potentials of AA, L-Dopa and Benserazide at unmodified sensors always overlap with each other, which is the major problem in their simultaneous determination by electroanalytical methods [4,5]. Therefore, improvement of the Figure 1. DPV results of 1.0 mM LD ve 1.0 mM BS on a)11.; b)12.; sensitivity and selectivity of the sensor towards L-Dopa c)13.; d)14.; e)15.; f)16. modified sensors and Benserazide has been a longstanding issue of researchers. To overcome this problem, a glassy carbon Interference study electrode was modified with electropolymerized film of 3-methylthiophene and single-walled carbon nanotube.
2. Experimental Instrumentation All the electrochemical operations (Cyclic voltammetry (CV) and Differential pulse voltammetry (DPV) were carried out by a BAS (Bioanalytical Systems, Inc.) 100 W electrochemical analyzer. The three electrode system Figure 2. DPVs for a mixture of 1.0 mM LD, 0.1 mM BS and 5.0 mM consisting of a glassy carbon disc working electrode AA at modified sensor in pH 7.0 PBS. (geometric area: 6.85 mm2, CHI), an nonaqueous + Ag/Ag reference electrode (CHI112) and a Pt wire coil 4. Conclusion auxiliary electrode (CHI) was used. Preparation of modified sensor The modified sensor has been used for investigation of Conducting polymer coating on the GCE was achieved the dermination of Levedopa and Benserazide in the in a three-electrode single-compartment cell containing presence of AA. The modified sensor has an excellent 150 mM 3-methylthiophene (3-MT) and 100 mM response and specificity for the electrocatalytic TBATFB (as electrolyte) dissolved in acetonitrile. The oxidation of Levedopa and Benserazide in PBS (pH polymer film was grown on GCE by CV from (-200) to 7.0). Linear calibration curves for DPV analysis were (+2000) mV at 50 mV/s for 14 cycle. N,N- obtained. By obtaining very low LOD, Levedopa -5 -5 dimethylformamide (DMF) dispersions of the single- (1.77x10 M) and Benserazide (9.7x10 M) can be walled carbon nanotubes (SWCNT) were prepared at determined simultaneously in the presence of interfence different concentrations, 0.2%, 0.5%, 1.0% (mg/μL). such as AA. Modified sensors while acquiring, 3-MT films, are coated above and below of the SWCNT-COOH on the References GCE surface. For this purpose, different volumes (10, [1] Anal. Chem. 73, (2001), 1196. [2] Anal. Chem. 71, (1999), 1055. 20 µL) of SWCNT/DMF dispersions were added [3] J. Braz. Chem. Soc. 21(8), (2010), 1572. dropwise on poly (3-MT) film or bare GC electrode and [4] J. Electroanal. Chem. 561, (2004), 173. [5] Anal. Chem. 68, (1996), 2084. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0129
Simultaneous determination of levodopa and carbidopa in the presence of ascorbic acid using nanostructured electrochemical sensor based on 3- methylthiophene and MWCNT
Ebru Kuyumcu Savan1* and Gamze Erdoğdu2 1Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, İnönü University, Malatya, Turkey 2Department of Chemistry, Faculty of Science, İnönü University, Malatya, Turkey *Presenter: [email protected]
1. Introduction AA at modified sensor in pH 7.0 PBS. Parkinson’s disease is believed to be related to low levels of the neurotransmitter dopamine in the brain. Therefore, the dopamine precursor levodopa is employed for its treatment. For better therapeutic effect and lower toxicity, carbidopa is administered in association with levodopa in pharmaceutical formulation containing 10–25% of carbidopa [1]. For simultaneous determination of levodopa and carbidopa a glassy carbon electrode was modified with electropolymerized film of 3-methylthiophene (3-MT) and multi-walled carbon nanotube. Utilizing the developed method, determination of the two compounds has been carried out in pharmaceutical Fig.3. DPVs for a mixture of 1.0 mM LD, 0.1 mM CD and 5.0 mM AA formulations, water and urine samples. at modified sensor in pH 7.0 PBS.
2. Experimental Table 1. Electrochemical determination of LD and CD in Sinemet tablet All the electrochemical operations were carried out by a BAS Tablet (mg) Found (mg) Recovery% 100 W electrochemical analyzer with three electrode system. Conducting polymer coating on the GCE was achieved Sample LD CD LD CD LD CD containing 150 mM 3-MT and 100 mM TBATFB (as electrolyte) dissolved in acetonitrile by CV. Modified sensors 1 2.262 0.226 2.448 0.229 108.2 101.4 while acquiring, poly(3-MT) films, are coated above and below of the MWCNT-COOH on the GCE surface. 2 2.262 0.226 2.092 0.216 92.49 95.51
3. Results and Discussion 3 2.262 0.226 2.078 0.230 91.85 101.4
Simultaneous determination ol LD and CD 4 2.262 0.226 2.238 0.224 98.94 99.16
5 2.262 0.226 1.897 0.228 83.86 100.6
Mean 95.06 99.60
SD 8.12 2.20
RSD% 8.54 2.21
RE% 4.94 0.40
Fig.1. DPV results of 1.0 mM LD ve 0.1 mM CD on a)1.; b)12.; c)13.; 4. Conclusion d)14.; e)15.; f)16. modified sensors The modified sensor has an excellent response and specificity for the electrocatalytic oxidation of Levedopa and Carbidopa.
References [1] Bioelectrochemistry. 93, (2013), 15–22.
Fig.2. DPVs for a mixture of 1.0-5.0 mM LD, 0.1 mM CD and 5.0 mM 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0130
An investigation of the effect of 2,4-dithio-phenoxy-1-iodo-4-bromo benzene molecule on rat liver and kidney tissue
Eda Çınar Avar1*, Elif Loğoğlu1 and Şule Coşkun Cevher2
1Gazi University, Faculty of Sciences, Department of Chemical, Ankara, Turkey 2Gazi University, Faculty of Sciences, Department of Biology, Ankara, Turkey
*Presenter: [email protected]
1. Introduction Table 1. Results from female rat liver MDA, GSH, AA, NO levels and MPO activity Nowadays fungal infections, tuberculosis, cancer and AIDS have become the main cause and the most MDA GSH AA MPO NOX important complexities of death and/or morbidity for the (nmol/ (nmol/g (nmol/g (nmol/g (nmol/g people who had an organ transplant and their immune g tissue) tissue) tissue) tissue) system depressed (1,2). Triazole antifungal compounds tissue) like fluconazole and voriconazole function inhibiting Group 1 122.8± 22.7±4. 3.5±0.2 0.7±0.1 436.7± the lanosterol cytochrome P450 14α-demethylase 28.8a 6a a 0a 18.2a (CYP51) enzyme. However, clinical values, relatively Group 2 135.3± 28.4±4. - 0.7±0.0 426.8± b b b b high toxicity, the emerge of drug resistance and 17.3 2 8 36.2 Group 3 77.2±4. 19.3±1. - 0.4±0.0 477.7± pharmacokinetic shortcomings of these compounds are c c c c limited because of their lack of antifungal activities. 1 6 2 16.7 Group 4 57.5±4. 18.8±1. 2.9±0.2 0.4±0.0 450.2± Broad spectrum antifungal agents with low toxicities are 5d 9d d 2d 9.4d still needed in despite of the recent developments (3,4). Group 5 48.6±7. 18.9±1. 2.7±0.4 0.4±0.0 426.3± In this sense the antifungal and antibacterial effects of 7e 2e e 2e 15.0e the newly synthesized thio halo-benzene derivative 2,4- For MDA levels : a-c, a-d, a-e, b-c, b-d, b-e, c-e p< 0.05 dithio-phenoxy-1-iodo-4-bromo benzene have been revealed in previous studies. This compound has similar For GSH levels : a-c, a-d, a-e, b-c, b-d, b-e p< 0.05 carbon structure with commonly used antifungal drug fluconazole, not to mention that it is more active than For AA levels: a-d, a-e p< 0.05 low concentrations of fluconazole. For MPO activity: a-c, a-d, a-e, b-c, b-d, b-e p< 0.05 2. Methods In this study, effects of previously proved as an For NOx levels: a-c, b-c, c-d, c-e , d-e p< 0.05 antibacterial and antifungal molecule 2,4-dithio- phenoxy-1-iodo-4-bromo benzene (C H S IBr) on The effects of this two molecule -fluconazole and newly 18 12 2 synthesized antifungal and antibacterial 2,4- mammal liver tissue and mammal kidney using dithiophenoxy-1-iodo-4-bromo benzene on mammal biochemical methods. 30 adult Wistar albino rats between the range of 150-200 gr have been used for this tissues examined on both male and female rat liver and study. Total 6 female rats have been used as subjects in kidney tissues. This effects on mammal tissues this experiment. Rats have been given fluconazole as examined as liver and kidney MDA, GSH, AA, NO well as 2,4-dithio-phenoxy-1-iodo-4-bromo benzene levels and MPO activity. Liver MDA, GSH, NO, AA orally, each dissolved in alcohol, once in a week for 4 levels and MPO activity of female rats have been given weeks. All subjects separated into 5 groups: a control in Table 1. These two new antioxidants considered to group, alcohol control, fluconazole group (0.28 mgr/100 be used to eliminate the free radicals in the chemical gr) and two different doses of 2,4-dithio-phenoxy-1- metabolism when GSH and AA levels from all groups iodo-4-bromo benzene (0.112 mg/100 gr and 0.056 are compared. Changes in MPO activity indicates that mg/100 gr). 2,4-dithio-phenoxy-1-iodo-4-bromo benzene molecule doesn’t contribute to neutrophil infiltration as well as 3. Results and discussion fluconazole. It is concluded that this newly synthesized antifungal compound does not cause any oxidative When 2,4-dithio-phenoxy-1-iodo-4-bromo benzene damage in kidney tissue, especially on males. molecule and fluconazole compared, it is shown that 2,4-dithio-phenoxy-1-iodo-4-bromo benzene does not References cause any oxidative damage on liver tissue particularly [1] S.K. Fridkin and W.R. Jarvis, Clin. Microbiol. Rev. 9 (1996), pp. 499–511. on female rats, in fact it is even acts like an antioxidant [2] J.R. Wingard and H. Leather, Biol. Blood Marrow Transplant. 10 (2004), pp. because of its low MDA levels (lower than control 73–90. [3] P. Kale and L.B. Johnson, Drugs Today 41 (2005), pp. 91–105. group). [4] S. Sundriyal, R.K. Sharma and R. Jain, Curr. Med. Chem. 13 (2006), pp. 1321–1335.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0131
The Effect of the para and meta Positions in Immobilized New Supports for Determination Phosmate
E. Hasanoğlu Özkan1*, N. Kurnaz Yetim1,2, N. Sarı1 and A. Dişli1
1 Department of Chemistry, Gazi University, Ankara, Turkey 2 Department of Chemistry, Kırklareli University, Kırklareli, Turkey
*Presenter: [email protected]
1. Introduction pesticide determination of 2AEPS-(p-F-Tet-1H)-AChE and 2AEPS-(m-F-Tet-1H)-AChE have made more As is known, enzyme is immobilization by interactions easily interact with phosmet insecticide. The apparent between the support and the enzyme such as covalent pesticide effect of the immobilized supports were bonding, hydrogen bonding and Van Der Waals forces compared, and this showed that the 2AEPS-(p-F-Tet- [10]. If a polymer-based nano-sphere supports have 1H)-AChE was higher than 2AEPS-(m-F-Tet-1H)- electronegative groups like Oxygen, nitrogen and AChE. Probably, stereo chemical structure of 2AEPS- fluorine may be useful for increasing the enzyme (p-F-Tet-1H)-AChE has been protected the three- stability via hydrogen bonding attachment [11]. So, the dimensional structure of the enzyme by means of surface on which the enzyme is immobilized has several hydrogen bonds. vital roles to play such as retaining of tertiary structure in the enzyme through hydrogen bonding. Acetylcholinesterase (AChE) is crucial enzyme in the central nervous system of living organisms [12]. The inhibition of AChE activity by organophosphorus (OP) compound is an irreversible process. In this process, AChE is inactivated. OP compounds, commonly used as insecticides [13]. AChE is a serine protease enzyme. The inhibition of AChE catalytic activity by OP is caused due to phosphorylation of serine residue [14].
2. Experimental Figure 1 Hydrogen bonds in between enzyme and support material and photography related with a. Immobilization of AChE on nanomaterial phosmet insecticide (2AEPS-(m/p-F-Tet-1H) After dissolving enzyme in pure water (50 mL, 3.6 x -1 10-4 gL ), 2AEPS-(m-F-Tet-1H) and (AEPS-(p-F-Tet- References 1H) polymers (0.5 g) were placed to a 2 mL of 3.6 x 10- 4 gL-1 of AChE. This solution was diluted to 10 ml and [1] Beatriz M. Brena and Francisco, Batista-Viera, at room temperature in a shaking water bath for 8 h. The Methods in Biotechnology: Immobilization of Enzymes immobilized polymers were separated and the free and Cells, Second Edition Edited by: J. M. Guisan © enzyme was removed by washing with phosphate buffer Humana Press Inc., Totowa, NJ. and then stored at + 4 °C. Saturation ratio was [2] Hasanoğlu Özkan E, Kurnaz Yetim N, Tümtürk H, determined as 97.60 % and 93.70 % for 2AEPS-(m-F- Sarı N (2015) Dalton Trans 44: 16865-16872 Tet-1H) and 2AEPS-(p-F-Tet-1H) respectively, from [3] Periasamy AP, Umasankar Y, Chen SM (2009) A absorbance value in 412 nm. Review,Sensors 9: 4034-4055 [4] Buckley NA, Roberts D, Eddleston M (2004) BMJ b. Study on phosmate insecticide 329:1231 N-(Mercaptomethyl) phthalimide S-(O,O-dimethyl [5] Warner J, Andreescu S (2016) Talanta 146:79–284 phosphorodithioate) was dissolved in Acetonitryl:H2O (1.37 x 10-7 mol/L; 1:4, v/v) and its solutions were prepared in between 10 μL - 50 μL. The absorbance changes at 412 nm was taken into account for studied phosmate solutions.
3. Conclusion The first time has been presented in this study, ligated new tetrazole derivatives on sphere have been synthesized for the identification of organophosphates. AChE immobilization has been successfully fabricated for the detection of pesticide. Even for this reason, in
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0132
An ultra-sensitive PtNPs@Graphene/Nafion electrochemical sensing-platform for detection of silodosin in human plasma
E. Er1*, H. Çelikkan2 and N. Erk1
1 Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University, Ankara, Turkey 2 Department of Chemistry, Faculty of Science, Gazi University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction A well-defined and irreversible oxidation peak at 714 mV was observed on the surface of PtNPs@GRP/NFN The enlargement of the prostate gland is common in modified electrode using AdsDPV. Under optimized men with an increasing percentage at least 50% of men conditions, PtNPs@GRP/NFN sensor exhibited an aged over 50 years have histological evidence of benign excellent analytical performance in the detection of SIL prostatic hyperplasia (BPH). Silodosin (SIL), α - 1 at nano-molar levels. The linear concentration range for adrenoreceptor antagonist in alpha-blockers class, is a SIL was found to be 1.0-290 nM with a lower detection novel therapeutic agent for the treatment of the signs limit at sub-nanomolar level. and symptoms of BPH. It relieves the muscles of the urinary bladder and prostate tract by selectively 3. Conclusion affecting the symptoms of BPH. The recommended dosage of SIL to relieve is 8 mg per day as it indicates Herein, we report a fabrication of new-generation the best selectivity at this dosage [1–2]. Therefore, the graphene-based electrochemical sensing platform for determination of SIL at low-level has a great importance the detection of SIL in human plasma. PtNPs@GRP especially in real samples [3]. In this point, we was effectively synthesized from GO and platinum salt proposed a novel electrochemical nano-platform based using a single-step chemical reduction process. on Platinum nanoparticles supported graphene/nafion PtNPs@GRP/NFN sensor exhibited an extraordinary (PtNPs@GRP/NFN) nanocomposite material for the analytical performance owing to its owing to its unique electrochemical sensing of SIL using adsorptive physical and chemical properties such as high surface stripping differential pulse voltammetry (AdsDPV). area, unique electrical conductivity, excellent electrocatalytic and electrochemical activity. In 2. Experimental addition, proposed sensor enable to detect the SIL at Platinum nanoparticles/graphene (PtNPs@GRP) nano-molar level. It is concluded that nanocomposite was produced from graphene oxide PtNPs@GRP/NFN sensor is a promising (GO) via single-step reduction method (Figure 1) [4-5]. electrochemical sensing-platform for the determination The formation of PtNPs@GRP was confirmed by x-ray of SIL in real samples. diffraction (XRD) and Transmission electron microscopy (TEM). References [1] M. Yoshida, Y. Homma, K. Kawabe, Exp. Opin. on Invest. Drugs 16 (2007) 1955. [2] X. Zhao, Y. Liu, J. Xu, D. Zhang, et al., J. Chromatogr. B 877 (2009) 3724. [3] E. Er, H. Çelikkan, N. Erk, M.L. Aksu, Electrochim. Acta 157 (2015) 252–257. [4] W.S. Hummers, R.E. Offeman, J. Am. Chem. Soc. 80 (1958) 1339. [5] T.Q. Xu, Q.L. Zhang, J.N. Zheng, et al., Electrochim. Acta 115(2014) 109–115.
Figure 1. Schematic presentation of the preparation process of PtNPs@graphene nanocomposites
For the fabrication of proposed sensor, PtNPs@GRP solution containing NFN (0.25%, v/v) was prepared to constitute the PtNPs@GRP/NFN nanocomposite, and followed by the modification of glassy carbon electrode (GCE) surface with PtNPs@GRP/NFN nanocomposite.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0133
Use of Bacterial Cellulose Membrane in the Removal of Azo Dyes
E.P. Çoban1*, U.C. Sağlam1, H. H. Biyik1
1 Department of Biology, Adnan Menderes University, Aydın, Turkey
*Presenter:[email protected]
1. Introduction The use of dye materials is widely known in textile, plastic and paper industries [1]. The mixture of dye substances with natural water disrupts the ecological balance of water and its chemical content has a negative effect on living things. The preferred method of removing of dyes is the use of activated carbon. Although the method is effective, regeneration and reuse is a disadvantage due to cost and decrease in activity [2]. For this reason, Bacterial cellulose; a low-cost, easy to obtain Figure 1 The initial image at different concentrations and simple, with a fine reticulated pore structure and flexible absorbent material, has been intended as an alternative. For of aniline blue dye this purpose, bacterial cellulose synthesized by Gluconacetobacter hansenii HE1 bacteria is being researched for its removal effects of Azo dye such as Aniline Blue, a Figure 2 60 minutes after widely used dye in textile. the initial image at different concentrations of aniline 2. Material and Method Material blue dye The Aniline Blue dye (CAS No. 66687-07-8, Sigma). Gluconacetobacter hansenii HE1 strain used in this study was provided from Adnan Menderes University Microbiology Table 1 Effect of bacterial cellulose on Aniline blue removal Laboratory stock cultures. at 585 nm
Production and purification of cellulose G. hansenii HE1 strain was inoculated in HS (Hestrin- Schramm) (2% glucose, 0.5% yeast extract, 0.5% polypeptone, 0.675% Na2HPO4, 0.115% citric acid) broth and was allowed to produce cellulose after an incubation period of 10 days at 300C [3]. 4% NaOH and 6% acetic acid solutions were used for purification and dried by lyophilisation [4].
Dye removal Removal of dyes with bacteria cellulose at 200 mg/L solution Batch adsorption assay was carried out by shaking.50 mL of yielded much better results than other concentrations. The aniline blue solution was prepared at different concentrations results show that bacterial cellulose with a loose network, (50,100 and 200 mg/L).1g of dried bacterial cellulose was porous and nanofibril properties can be used in the removal of added to the solutions and the solutions pH was set to a pH of dyes. 7 by using 1.0 N HCl and 1.0 N NaOH. It was kept on shaker at 120 rpm at 280C. After, a period of 10 minutes and Acknowledgements: This research was supported by spectrophotometric readings were taken at 585 nm. In addition supported TUBITAK BIDEP-2209. Project Number: pH reading was made to observe pH changes. 50 mL of 1919B011501637. Aniline Blue (50 mg/L) was used as a positive control, 50 ml of distilled water containing cellulose was used as a negative References control [1]. [1] Pansar PS, Chavan YV, Bera MB, Chand O, Kumar H. Evaluation of Acetobacter strain for the production of microbial cellulose. Asian 3. Results and Discussion J. Chem. 2009; 10:99–102. Initial spectrophotometric measurements were found to be 0.3325 at 50 mg/L; 0.4116 at 100 mg/L and 1.4300 at 200 [2] Bhavna VM, Satish VP. Bacterial cellulose of Gluconoacetobacter mg/L. While measurements made at 10 minute intervals hansenii as a potential bioadsorption agent for its green environment showed a fading in colour, a spectrophotometric measurement applications. J. Biomat. Sci. 2014; 25(18):2053-2065. after 60 minutes were 0.0659; 0.1057 and 0.2026 respectively. [3]. Hestrin S, Schramm M. Synthesis of cellulose by Acetobacter Despite the solution`s starting pH of 7, as the colour fade the xylinum preparation of freeze dried cells capable of polymerizing pH became alkaline. After 60 minutes pH observed were 8.9, glucose to cellulose. Biochem J. 1954; 58(2):345-352. 8.8, and 8.7 respectively. While the positive control containing [4]. Hyun JY, Mahanty B, Kim CG. Utilization of makgeolli sludge Aniline blue solution had a pH of 8.7 and a filtrate (MSF) as low-cost substrate for bacterial cellulose production spectrophotometric reading of 2.3868, negative containing by Gluconacetobacter xylinus. Appl Biochem Biotechnol. bacterial cellulose and distilled water showed a 2014;172(8):3748–60. spectrophotometric reading of 0.0336 and a pH of 7.2.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0134
Vapor-Phase Deposition of Polymers Asa Simple and Versatile Technique to Generate Paper-Based Microfluidic Platforms for Bioassay Applications
E. Babur1* and G. Demirel1
1 Department of Chemistry, Gazi University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction Paper-based sensor platforms having patterned fluidic channels have a great potential in food, environment, and health areas. Furthermore, paper-based materials constitute suitable platforms in terms of easy attainability and processability. Especially paper-based sensor platforms’ replacing the conventional diagnostic kits dependent on electronic gadgets can be estimated to be popular considering both the cost and user-friendly usage. However, certain difficulties have already being seen on the issues of sample flow control, decreasing the limit of detection, and repeatability in the paper- based sensor platforms. Especially various difficulties have been encountered in the formation and application of hydrophobic barriers on the hydrophilic paper to Figure 1 Schematic representation of the fabrication provide a suitable flow [1,2]. In this study, we process of polymer deposition on a paper substrate demonstrate an alternative approach to fabricate paper- [inset: polymerization mechanism of PPX] (a), based sensor platforms through a vapor-phase polymer sandwich array for patterning of the paper (b) and deposition technique. Furthermore, analysis of certain colored water droplets on polymer deposited paper (c). target molecules such as glucose, protein, ALP, ALT and uric acid are displayed using fabricated platforms. 3. Results 2. Experimental We have demonstrated a technique for fabrication of The conformal coating of poly(chloro-p-xylene) [PPX] paper-based sensor platforms through vapor phase films on paper samples (Whatman no. 1 polymer deposition approach. The fabricated paper chromatography paper) were performed using a SCS- platforms were successfully utilized for the detection of PDS2010 deposition system. A hydrophobic dichloro- varying biological target molecules including glucose, [2.2]-paracyclophane molecule was used in the protein, ALP, ALT, and uric acid. Given its deposition process as a starting monomer. The polymer environmental friendly, solvent-free, and material deposition process was started by placing proper independent nature of vapor phase polymerization amounts of monomer (0.01 g – 2.0 g) into evacuated method may offer new possibilities in the field of sublimator chamber. These monomers were then biosensor applications. evaporated at ~175 °C and converted to radicalic monomers by pyrolysis (~695 °C). They were Acknowledgements: This work was supported by the subsequently deposited and polymerized onto paper TUBITAK (Grant 112T560) and Gazi University samples. All process was carried out under vacuum (05/2015-19). Authors would like to thank Hakan condition (32 mTorr). The corresponding PPX thickness Erdogan for useful discussions. on paper samples was controlled through the amount of the loaded monomer. The hydrophilic channels on paper 4. References samples, which allow to transport the analyte solutions [1] E. Carrilho, A. W. Martinez and G. M. Whitesides, via capillary penetration, were created using a metal Anal. Chem., 2009, 81, 7091–7095. mask with desired pattern. The paper samples were sandwiched between metal masks and magnets [3]. [2] A. W. Martinez, S. T. Phillips and G. M. Whitesides, Anal. Chem., 2010, 82, 3–10.
[3] G. Demirel and E. Babur, Analyst, 2014, 139, 2326- 2331.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0135
Sensing Studies of a Amine Functionalized Calixarene Derivative Coated QCM Biosensor in Aqueous Solution
F. Temel1*, E. Ozcelik1, M. Akpinar1 and M. Tabakci1
1 Department of Chemical Engineering, Selçuk University, Konya, Turkey
*Presenter: [email protected]
Abstract There are limited numbers studies about Biosensors are device which have properties of macromolecules as biochemical sensors even though biological sensing to use for controlling and sensing of there are many studies about polymeric materials. In biologic analytes. In biosensor applications, there are macromolecules, there are few studies about calixarenes several methods which are electrochemical, as biochemical material. Synthesis and derivatization of calorimetric, optical and acoustic systems for calixarenes which can be easily detected desired determination and sensing biologic analyte-biochemical biological analyte and easily preparation of their films interaction [1]. on QCM crystals show that calixarenes can be used to detect biological analytes widely. In our previous Quartz Crystal Microbalance (QCM) is a sensor device works, we have also synthesized some calixarene which is simple, ease of use, low cost, shorter analysis compounds and they has been investigated their sensing time for detection. During detection, mass accumulation properties for volatile organic compounds. In this study, occurs on quartz surface and this causes frequency shift. we have prepared a calixarene derivative, its sensor QCM device can be used many application like antigen– films and investigated its sensing abilities for bioanalyte antibody, enzyme-substrate interaction, drug carrier, by calixarene-coated QCM system. volatile organic compounds detection [2]. Relationship between frequency and mass change in liquid contact 1. References measurement can be expressed Sauerbrey equation [1] Corcuera, J. I. R. D., Cavalieri, R. P., 2003 “Biosensor” , Encyclopedia of Agricultural, Food, and A Biological Engineering, 119 – 123. m f C f (1) 2 f 2 0 [2] Lucklum, R., Hauptmann, P., 2006, “Acoustic microsensors – the challenge behind microgravimetry”, where ∆m is mass change on sensor surface, ∆f is Anal. Bioanal. Chem., 384, 667 – 682. frequency shift, ρ is density of quartz, µ is shear modulus of quartz, A= active area of quartz and f0 is [3] Sauerbrey, G., 1959, “The use of quartz oscillators fundamental frequency of the of QCM crystal. for weighing thin layers and for micro-weighing”, Z. Phys. 155, 206–222. Calixarenes, are macrocyclic molecules which have unique three–dimensional structure and unlimited [4] Temel, F., Tabakci, M., 2016, “Calix[4]arene coated derivatization potential. They can be synthesized by QCM sensors for detection of VOC emissions: condensation of p-tert-butylphenol with formaldehyde. Methylene chloride sensing studies”, Talanta, 153, 221 Calixarenes can be used for sensing applications [4]. – 227.
Figure 2 Amine Functionalized Calix[4]arene derivative 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0136
Detection of Escherichia coli using Quartz Crystal Microbalance Sensor: A Study Design
Mehmet Çağrı Soylu1, Fatma Betül Köşker1* and Keziban Canıkara1
1 Department of Biomedical Engineering, Erciyes University, Erciyes, Turkey
*Presenter: [email protected]
1. Introduction The stages are illustrated in Figure 2. Concentration of E. coli, the amount of BSA and detergent, flow rate, Escherichia coli (E. coli), a natural member of human immobilization, Signal-to-noise ratio (SNR) and signal intestinal microbiota, is one of the leading matching algorithm will be optimized during the microorganism some strains of which is a cause of experiments. foodborne or waterborne diseases via fecal contamination [1]. In this study, rapid, simple and sensitive genetic detection of non-pathogenic E. coli K-12 MG1655 strain has been aimed without the need of DNA isolation, purification and amplification.
2. Materials and Method Figure 1. Experimental design All the probe oligonucleotides, reagents and E. coli K- 12 MG1655 strain (ATCC 47076) will be obtained SNR must be above 3. The target level of detection is determined as 1010 copy/ml which is expected to be commercially and the bacteria will be cultured. 5 Phosphate buffered saline (PBS) will be used for increased using microspheres to 10 copy/ml. dilution. The ssDNA will be designed based on the chosen conserved gene region (i.e. uidA gene). The 3. Results ssDNA probe will be modified at 5’ end with C6-SH. A The designed and optimised system for non- synthetic target DNA with complementary sequence of probe DNA will be used for detection. The sensor pathogenic E. coli will be used for detection of specificity will be determined using an oligonucleotide pathogenic and toxigenic E. coli strains at the next with the same sequence of probe DNA. level. The experimental design is shown in Figure 1 and the main stages of the detection procedure are: I. Surface modification with 3- References Mercaptopropyltrimethoxysilane (MPS) for [1] Lee, H., et al., Rate and molecular spectrum of electrical insulation [2], spontaneous mutations in the bacterium II. Immobilization of the ssDNA probe, Escherichia coli as determined by whole-genome III. Blocking with Bovine Serum Albumin (BSA) to sequencing. Proceedings of the National prevent adsorption on sensor surface, Academy of Sciences, 2012. 109(41): p. E2774- IV. Extracting E. coli DNA with high temperature E2783. (97 ºC) and detergent, [2] Soylu, M.C., W.-H. Shih, and W.Y. Shih, Insulation V. Driving the solution including target DNA via by Solution 3-Mercaptopropyltrimethoxysilane peristaltic pump, (MPS) Coating: Effect of pH, Water, and MPS VI. Analyzing the frequency change with impedance Content. Industrial & Engineering Chemistry analyzer, Research, 2013. 52(7): p. 2590-2597. VII. Examining the surface morphology via scanning electron microscopy (SEM).
Figure 3. Study design and detection procedure
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0137
A new sensitive electrochemical method for simultaneous determination of amlodipine and telmisartan drug
F. Kartal1*, N. K. Bakirhan1 and S. A. Ozkan1
1 Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction Twynsta is used to treat high blood pressure (hypertension). Lowering blood pressure may lower your risk of a stroke or heart attack. Twynsta contains a combination of amlodipine (AML) and telmisartan (TLM). AML is a calcium channel blocker. AML relaxes (widens) blood vessels and improves blood flow. TLM is an angiotensin II receptor antagonist. TLM keeps blood vessels from narrowing, which lowers blood pressure and improves blood flow. AML
Up to date, AML and TLM compounds have been studied with spectrophotometry, liquid chromatography. However, there is no information about simultaneous determination of these two compound with electrochemical methods. And also, there is no quantitative developed method has been proposed for its analysis in dosage forms by electrochemical method.
2. Experimental Figure 1. TLM In this work the voltammetric behavior of AML and TLM disodium was studied at a glassy carbon. The aim of this work is to carry out a detailed investigation on 4. Conclusion the electrochemical behavior and possible oxidation mechanism of AML and TLM disodium by using cyclic, Simple, selective, sensitive, fully validated, rapid, and reliable adsorptive stripping square wave voltammetry differential pulse, and square wave voltammetric methods were applied for the simultaneous analysis of techniques. For this purpose, AML and TLM were AML and TLM in pharmaceutical dosage form, studied in various supporting electrolyte including Twynsta. Precision and accuracy of developed method H SO , phosphate, acetate and Britton-Robinson buffers 2 4 was checked by recovery studies. These techniques did (pH values between 0.3–10.0) containing 10% not require sample pre-treatment or any time-consuming methanol. The scan rate studies were realized in 0.5 M extraction step prior to drug assay in dosage forms. H2SO4 solution for glassy carbon electrode, understanding the mass transfer process to the electrode surface. When the scan rate was varied from 5 to 750 mVs−1 in 1×10−4 M AML and TLM disodium solution, a linear dependence (r≥0.999) of the peak intensity Ipa (µA) upon the scan rate (mV.s−1) was found for a glassy carbon electrode, demonstrating an adsorption process.
3. Results & Discussion Voltammetric method exhibited linear dynamic responses for simultaneous assay of AML and TLM in the concentration range between 1.0×10-7 M – 1×10-4 M and 1.0×10-7 M – 1.0×10-5 M, with detection limits of 0.654 nM and 22.6 nM, respectively.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0140
A novel electroanalytical nanosensor based on AgNPs nanoparticles for determination of antiviral drug tenofovir
G. Ozcelikay1*, B. Dogan-Topal1 and S.A. Ozkan1
1Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06100 Ankara, Turkey
*Presenter: [email protected]
1. Introduction The results revealed that the oxidation of TEN is an irreversible pH-dependent process in an adsorption- Tenofovir Disoproksil Fumarat (TEN) is an antiviral controlled mechanism. The calibration curve was linear drug active compound which is used for the treatment of in the concentration range of 8x10-8-1x10-6M with a the AIDS. The voltammetric oxidation of TEN was detection limit of 4,30x10-9M. investigated at silver nanoparticles modified glassy carbon electrode using cyclic (CV), Osteryoung Square Wave Stripping (OSWSV) Voltammetry over a wide pH range.
For the analytical application, operational parameters have been optimized. The dependence of intensities of
currents and potential on pH, concentration, scan rate, (µA) p nature of the buffer was investigated. i
2. Methods
a. Reagents and Apparatus -3 Ep (mV) A stock solution of 1.0x10 M was prepared by dissolving the compound in bidistilled water. Standard Figure 1. OSWSV of 4x10-6 M TEN at bare electrode solutions were prepared by serial dilution of the stock (blue line) and AgNps modified carbon electrode (red solution with selected supporting electrolyte. line). The CV and OSWSV experiments were performed using a BAS 100W electrochemical analyzer. The utilized electrodes were: silver nanoparticles modified The OSWSV method was successfully applied for the glassy carbon as a working electrode; a platinum wire as analysis of TEN from pharmaceutical dosage forms. No a counter electrode and an Ag/AgCl (BAS; 3M KCl) as electroactive interferences from the tablet excipients. a reference electrode. 4. Conclusion OSWSV conditions: pulse amplitude, 35 mV; frequency, 30 Hz; potential step 8 mV. The parameters In the present work, the electrochemical behavior of of stripping methods were also optimized. TEN was investigated by CV and OSWSV. In these investigations, the effect of the pH of the buffer solution AgNP amount was investigated for the well-defined and potential sweep rate were described. This study peak shape and peak current. 5.0–15.0 µL AgNP demonstrated that modification of GCE with AgNPs suspensions were dropped on GCE surface. The was a new and sensitive application for the optimum result was obtained with 10.0 µL AgNP electrochemical determination of TEN [1]. The method suspensions in pH 5.7 acetate buffer. was validated in accordance with ICH guidelines and the obtained results were within acceptable criteria. b. Analysis of tablets A weighed portion of the powder content equivalent to References 1x10-3M of tenofovir was transferred into a 50mL- calibrated flask and completed to the volume with [1] N. Karadas, B. Bozal-Palabiyik, B. Uslu, S.A. bidistilled water. Ozkan, Functionalized carbon nanotubes—With silver nanoparticles to fabricate a sensor for the 3. Results and Discussion determination of zolmitriptan in its dosage forms No previous electrochemical studies were available the and biological samples, Sensors and Actuators B sensitive anodic electroanalytical determination of TEN 186 (2013) 486–494 in its dosage forms.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0142
Heteroarylboronic Acid Loaded Nanostructures:
Synthesis of 5-Pyrimidylboronic acid
G. Taskor1* and N.Saygili1
1 Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction The objective of this work was to formulate a nanostructured possible biosensor with ability to choose the diols. Boronic acids bind covalently with 1, 2- or 1, 3-diols to generate five or sixmembered cyclic complexes. 5-Pyrimidylboronic acid has been synthesised by lithium-halogen exchange reactions on 5-bromopyrimidine, followed by reaction with triisopropylborate (Scheme 1). 5-Pyrimidylboronic acid was formulated as nanostructured lipid carriers (NLCs) and characterized for size, zeta potential and morphology.
2. Materials and Methods
Procedure for the Preparation of 5- Pyrimidylboronic acid [1]: To a solution of 5- Figure 1. Tem image of nanostructure (scale bar = 200 bromopyrimidine (5.50 g, 34 mmol) and nm) triisopropylborate (13.0 g, 69 mmol) in anhydrous THF (70 mL) at -78oC was added n-BuLi (1.6 M in hexane, 3. Results 22.0 mL, 35 mmol) dropwise. The reaction mixture was o Characterization of 5-Pyrimidylboronic Acid: Mp stirred for 4 h at -78 C then quenched with H2O (10 o 1 o >320 C; H NMR (DMSO-d ) δ 9.36 (s, 1 H), 9.17 (s, 2 mL) and allowed to warm to 20 C with stirring 6 H), 8.81 (s, 2 H, OH); 13C NMR (DMSO-d ) δ 161.84, overnight. The solvent was evaporated in vacuo and the 6 159.31. Anal. calc. for C H BN O ·0.5H O: C, 36.15; aqueous layer was taken to pH 10 with 5% NaOH and 4 5 2 2 2 H, 4.55; N, 21.08. Found: C, 36.47; H, 4.50, N, 20.80%. was then washed with diethyl ether. The aqueous layer was then acidified to pH 4 with 48% aq HBr to 5-Pyrimidylboronic acid loaded nanoemulsions precipitate 5-pyrimidylboronic acid as a white solid formulated for the development of novel boronic acid- (1.90 g, 45%). based biosensors.
4. Conclusion This work support the way for further studies on synthesis of pyrimidylboronic acids and regulation of their nanostructures. Boronic acid-based nanoemulsion sensors would be useful alternatives for the sensitive Scheme 1. Synthesis of 5-Pyrimidylboronic Acid and selective detection of biomolecules which have diols. Procedure for Preparation of Nanostructures [2]: A prewarmed oil phase (1 mL) consisting of fish oil and References 125 mg of 5-pyrimidylboronic acid dissolved in ethanol was gradually added to the prewarmed aqueous phase (4 [1] Saygili N., Batsanov A. S., Bryce M. R. Org. mL) containing 120 mg of egg phosphatidylcholine Biomol. Chem., 2004, 2, 852-857. (Lipoid E80), 10 mg of polysorbate 80 (Tween 80), and [2] Yadav S., Gattacceca F., Panicucci R., Amiji M. M. 10 mg of stearylamine. The resultant mixture was Mol. Pharmaceutics, 2015, 12, 1523-1533. stirred for 2 min using a homogenizer at 6000 rpm and ultrasonicated for 10 min using a probe sonicator at 22%amplitude and 50% duty cycle.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0143
Development of electrochemical biosensor based on graphene–chitosan composite for sensitive detection of vinclozoline
G. Bolat1*, O. Surucu1 and S.Abaci1
1Hacettepe University, Department of Chemistry, 06532 Ankara, Turkey
*Presenter: [email protected]
Abstract graphene matrix was used to fabricate the electrochemical sensor to determine the VZ. Pesticides are substances that are used to increase the Modification of the electrode surface and the agricultural production by preventing the crop losses application for the detection of VZ was carried out from insects, herbicides or fungi. As a result of wide use successfully. The high surface area of the composite of pesticides in agrochemistry, there is a possibility to greatly increased the surface loading of VZ as sorbent run-off these toxic compounds into natural water bodies material. and soil. Vinclozoline, (VZ), 3-(3,5-dichlorophenyl)-5-methyl-5- vinyl-1,3-oxazolidine-2,4-dione (Figure 1), is a dicarboximide type of non-systemic fungicide that is widely used for the control of several species of fungi in vines (such as grapes), strawberries, vegetables and fruit by inhibiting spore germination [1]. However, VZ, has Figure 1 Structure of vinclozolin. toxicity and functions as potential endocrine disruptor that produces malformations in humans [2]. Also, the low-solubility of fungicides in water may lead to serious environmental problems [3]. 1. References Considerable effort is being made to design sensitive [1] W.R. Kelce, E. Monosson, L.E. Gray, Recent analytical methods for the detection of pesticides. The Progress in Hormone Research 50 (1995) 449–453. mechanisms of reactions of dicarboximides and their [2] S. Mc Gary, P.F.P. Henry, M.A. Ottinger, electrochemical behavior are still not known in detail. Environmental Toxicology and Chemistry 20 The fabrication of electrochemical sensors based on (2001) 2487–2493. modified electrodes on the analytical determination of [3] O. Belafdal, M. Bergon, J.P. Calmon, Pesticide pesticides has great amount of importance due to the Science 17 (1986) 335–342. excellent sensing properties [4]. Therefore, it is [4] C.M.A. Brett, Pure Appl. Chem. 73 (2001) 1969– important to discover appropriate electrode materials 1977. to improve the performance for the pesticides sensing [5] J.D. Fowler, J.M. Allen, V.C. Tung, Y. Yang, B.H. [5]. Graphene films can be used as electrode materials Weiller, ACS Nano 3 (2009) 301–306. with electrocatalytic properties in their partially reduced [6] S. Stankovich, D.A. Dikin, G.H.B. Dommett, form. Graphene nanosheet (GN), in a honeycomb two- K.M. Kohlhaas, E.J. Zimney, E.A. Stach, R.D. dimensional (2D) sheet form, is a two-dimensional Piner, S.T. Nguyen, R.S. Ruoff, Nature 442 carbon material which possesses novel properties, such (2006) 282-286. as large surface-to-volume ratio, well biocompatibility, [7] T. Ramanathan, A.A. Abdala, S. Stankovich,D.A. well mechanical properties and high electrical Dikin, M. Herrera-Alonso, R.D. Piner, Nat. conductivity. Graphene-based materials and Nanotechnol. 3 (2008) 327-331. nanocomposites show obvious superiorities on sensing applications [6]. It has been reported that GR nanosheets could be electrodeposited onto electrodes through electrochemical reduction of graphene oxide (GO) solution. Chitosan (CS) is a linear hydrophilic nontoxic natural biopolymer that exhibits excellent film-forming ability. Also, CS has been applied to disperse nanomaterials. The GR–CS composite has been shown as a suitable electrode material for pesticide sensing, by facilitating the enrichment of pesticides on the surface and improving the sensitivity [7].
To the best of our knowledge, there is no report on the determination of VZ by using graphene-based nanocomposite to VZ sensor. In this study, chitosan- 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0141
Polydopamine Coated - SiNWs Target Surfaces for the Detection of Small Molecules in Laser Desorption/Ionization Mass Spectrometry
G. Şanlı1*, G. Demirel2 and Ö. Çelikbıçak1
1 Department of Chemistry, Hacettepe University, Turkey, 2 Department of Chemistry, Gazi University, Turkey
*Presenter: [email protected]
1.Introduction these surfaces as sample. In these studies, different target Matrix-assisted laser desorption/ionization mass spectrometry surfaces, produced by different polydopamine coating periods (MALDI-MS) is a surface-based technique that has been (3h, 6h and 24h) were also utilized to investigate effects of widely employed for the analysis/detection of biomolecules. polydopamine layer thickness on LDI-MS analysis (Figure 1). In this method, the choice of the suitable matrix and the [M+H+] signal of the acrivastin drug molecule was sample/matrix mixing ratio, the methods of the sample successfully observed by using polydopamine coated surfaces preparation and the way of sample introduction upon MALDI prepared by 3h and 6h time periods. However, LDI-MS signal plate can cause different consequences in mass spectral of acrivastine was disappeared on 24h polydopamine coated results. Apart from that, the excess amount of matrix SiNWs. In the case of angiotensin II and substance P studies, molecules makes difficult the analysis of the small analyte it was observed that signal intensities of both polypeptides molecules which can be observed under 1000 m/z in mass [1] were increasing by growing thickness of polydopamine layer spectra. To overcome these problems, reusable solid on SiNWs. These results represent that thin polydopamine surfaces were produced by polydopamine (PDOP) coating on layer on SiNWs are affective for detecting small molecules, silicone nanowires (SiNWs) and these surfaces were used as a while thicker polydomamine coatings are successful for laser desorption/ ionization (LDI) target in this study. In order relatively higher molecular weight compounds such as small to test the effects of PDOP thickness on laser polypeptides. desorption/ionization (LDI) process, the SiNWs were coated
with PDOP layer with different thicknesses by manipulating F A D +
PDOP deposition time (3h, 6h, 24h). Fabricated surfaces were ]
H
+
+ M
F ]
[ H F * + then characterized by various techniques such as XPS (X-ray + F F M
K F 2 [ 10 208 406 604 802 1000 m/z photoelectron spectroscopy), SEM (Scanning electron 10 208 406 604 802 1000 m/z * microscopy) and ellipsometry. Finally, performances of B * E
K+
fabricated surfaces as a LDI target were tested and evaluated +
] H * +
* M
[ + using some model drug and peptide molecules, such as; ]
* H * +
* Na+ K+ M acrivastine, angiotensin II and substance P in MALDI-TOF- * * [ 10 408 806 1204 1602 2000 m/z 10 508 1006 1504 2002 2500 m/z MS studies. * C * F
K+
* ** +
2.Materials and method ] +
* + ]
H Na + H
+ K +
* M
* M [ * * * [ F * * * The vertical aligned silicon nanowires were fabricated through 10 508 1006 1504 2002 2500 m/z 10 408 806 1204 1602 2000 m/z well-established metal-assisted chemical etching technique. [2] Within this context, p-type silicon wafers were first cleaned Figure 1: Acrivastine, angiotensin II and substance P analysis consecutive sonication in ethanol, acetone, and deionized on different PDOP coated surfaces. (A) acrivastin on 6h- water for 10 min. The wafers were then immersed into a H O PDOP. (B) Angiotensin II on 6h-PDOP (C) Substance P on 2 2 6h-PDOP. (D) acrivastin on 24h-PDOP. (E) Angiotensin II on and H2SO4 mixture having a volume ratio of 1:3 at 70°C for 60 min in order to remove metal and organic residues from 24h-PDOP. (F) Substance P on 24h-PDOP. silicon wafer surfaces. Afterwards, the silicon wafers were References transferred into HF solution for 1 min and subsequently [1] Çelikbıçak, Ö., Demirel, G., Pişkin, E., Salih, B., Small immersed into a PTFE baker containing 4.6 M of HF and 0.02 Molecule Analysis Using Laser Desorption/Ionization Mass M of AgNO (1:1, v/v) for 1 min. The samples were finally 3 Spectrometry on Nano-Coated Silicon with Self-Assembled immersed into a mixture of HF and H O (10:1, v/v) at 25°C 2 2 Monolayers. Analytica Chimica Acta, 2012, 729, 54-61. for 10-120 min. Afterwards, the wafers having desired [2] Li, X.; Bohn, P., Metal-Assisted Chemical Etching in nanowire lengths were removed and washed with deionized HF/H O Produces Porous Silicon. Applied Physics Letters (DI) water and nitric acid to remove by-products. To deposit 2 2 2000, 77 (16), 2572-2574. PDOP on SiNWs, the fabricated SiNW arrays were first immersed into a dopamine solution (pH=8.5, 2 mg/mL) for varying time intervals (3-24 h). The samples were then removed and cleaned with DI water and dried with N2 gas.
3. Results and Discussion Polydopamine coated SiNWs was employed as a LDI target and some model compounds having different molecular structures such as; acrivastine (348,4 Da), angiotensin II (1046,1 Da) and substance P (1347,6 Da) were applied onto
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0144
Molecular Identification of Aspergillus and Penicilium Species with ITS-PCR
H. Halil Bıyık1, Bahadır Törün1, Yusuf Geroğlu1, Esin Poyrazoğlu Çoban1, Gamze Başbülbül1
1 Department of Biology University of Adnan Menderes,
*Presenter: [email protected]
1. Introduction Classical parameters which used for identification of microfungi includes; microscopic morphology, Difficulties and confusions about identificatrion of fungi physiological tests, cultural and clinical properties. But with tradiotinal methods have turned researches to uncertanity of phenotipic chracters makes harder to molecular methods [1]. ITS is one of the polymorphic identify species with morphological methods. Therefore DNA sequences between fungal species, nowadays it is molecular approaches became an alternative method for seen as a good candidate in terms of determining fungi identification of fungi. Lyophilisation and liquid drying species correctly and with this application they can be is difficult techniques for preserving fungi mycels and deperated to a large extend. Aspergillus and Penicillium spores. These techniques are especially used for have both positive and negative effects on human stocking and preserving mycels and spores over 20 aktivities, and widely distributed species. Some of the years. species of this genus can be pathogenic while some of Table 1 Name of species and number of samples them have industriel importance [2]. In this study identified Aspergillus and Penicillium species in our stocks were identified with molecular methods and long term storage is provided.
2. Materials and Methods In study, Aspergillus and Penicilium species which previously isolated and identified with morphological methods and recorded at ADÜ Biology Department stocks were used. DNA isolations of the samples were made according to Tran-Dinh et al., (1999) [3]. DNA concentration and purity control of the samples were made with Nanodrop Spectrophotometer (Thermo). Universal ITS 1 and ITS 4 primers were used for molecular identification. PCR products were sent to Macrogen (Holland) company for sequencing and matched using BLASTn software.
3. Results and Discussion One hundered twenty samples were matched with GenBank using BLASTn software (GenBank; http://ncbi.nlm.nih.gov) and 20 of the samples were Aspergillus fumigatus, 12 of them were A.awamori, 9 4. Acknowledgements of them A.niger, 6 of them A.tubingensis, 9 of them This research was supported by supported Adnan Menderes A.terreus, 4 of them A.japonicus, 5 of them A.oryzae, University Research Fund. Project Number: ADU-BAP-FEF– 2 of them A.tamarii, 5 of them Penicilium commune, 6 10003. of them P.chrysegeum, 2 of them Fusarium sp., 3 of them Mucor circinelloides, 2 of them Lichtheimia References corymbifera, 1 of each Aspergillus versicolor, [5] Edman JC, Kovacs JA, Masur H, Santi DV, Elwood HJ, Sogin A.brassiliensis, A.flavus, Penicillium griseofulyum, P. ML (1986) Ribosomal RNA sequence shows Pneumocystis restrictum, Fusarium proliferatum, F. chlamydosporum, carinii to be a member of the fungi. Nature 334:519–522. Trichoderma saturnisporum, T. atroviride, T. [6] Logrieco A, Peterson SW, Wicklow DT (1990) Ribosomal harzinarum, Alternaria promicola, Purpurecilium RNA comparisons among taxa of the terverticillate penicillia. lilacinum, Cladosporium cladosporioides, Eurotium In: Samson RA, Pitt JI (eds) Modern concepts in Penicillium and Aspergillus classification. Plenum, New York, pp 343–356. cristatum and Cytospora sp. were found (Table 1). [7] Tran-Dinh, N., Pitt J.I., Carter D.A. 1999. Molecular genotype Mycelia and spores of Aspergillus and Penicillium were analysis of natural toxigenic and nontoxigenic isolate of lyophilizied and cathologed. Aspergillus flavus and A. parasiticus. Mycological Research, 103, 1485 –1490.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0147
Zinc-Nickel nanostructures coated f-MWCNT nanocomposite electrode for nonenzymatic glucose biosensing
Fatih Şen1, Yağmur Koşkun1, Hakan Sert1*, Gaye Başkaya1 and Aysun Savk1
1Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupınar University, Kütahya, Turkey
*Presenter: [email protected]
Abstract References Mesoporous ZnO-NiO architectures were prepared by [1] Liu, Q., Lu, X.B., Li, J., Yao, X., Li, J.H., (2007), thermal annealing of zinc-nickel hydroxycarbonate Biosens. Bioelectron. 22; 3203–3209. composites [1]. The resulting architectures are shown to [2] Zeng, Q., Cheng, J.S., Liu, X.F., Bai, H.T., Jiang, be assembled by many mesoporous nanosheets, and this J.H., (2011), Biosens. Bioelectron. 26; 3456–3463. results in a large surface area and a strong synergy [3] Ding, Y., Wang, Y., Su, L., Bellagamba, M., Zhang, between the ZnO and NiO nanoparticles [2]. The H., Lei, Y., (2010), Biosens. Bioelectron. 26; 542–548. obtained material was used as an electrode that responds to glucose over a wide concentration range (from 0.5 μM to 6.4 mM), with a detection limit as low as 0.5 μM, fast response time (<3s), and good sensitivity (120.5 μA·mM−1·cm−2) [3].
Figure 1. Cyclic voltammograms of the GC/MWNT/NiO in the presence of 0.01 M glucose at varying scan rates: (a) 10, (b) 20, (c) 40, (d) 60, (e) 80, (f) 100, (g) 150 and (h)200 mV s−1, respectively
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0148
Surface Plasmon Resonance Imaging (SPRi) on a Smartphone for Point-of-care Applications Hasan Guner1*, Erol Ozgur1, Guzin Kokturk2, Mehmet Celik3, Elif Esen2, Ahmet E. Topal1, Sencer Ayas4,
Yildiz Uludag2, Caglar Elbuken1 and Aykutlu Dana1
1UNAM, Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey 2 UEKAE-BILGEM, TUBITAK, Gebze/Kocaeli, 41470, Turkey 3 Department of Computer Engineering, Middle East Technical University, Ankara, 06800, Turkey 4 Department of Radiology, Stanford School of Medicine, Palo Alto, CA 94304, USA
*Presenter: [email protected]
1. Introduction Figure 1. Surface plasmon resonance imaging platform integrated with a smartphone We demonstrate an on-chip plasmonic imaging platform integrated with a smartphone to be used in the field with high- throughput biodetection. Inexpensive and disposable SPR substrates are produced by metal coating of commercial Blu- ray discs [1,2]. Real-time bulk refractive index change measurements yield noise equivalent refractive index changes -5 as low as 4.12 x 10 RIU which is comparable with the detection performance of commercial instruments. We have shown capture of mouse IgG antibodies by immobilized layer Figure 2. Grating coupled SPRi sensor chip of rabbit anti-mouse (RAM) IgG antibody with nanomolar level limit of detection. Our approach in miniaturization of 3. Results SPR biosensing in a cost-effective manner could enable realization of portable SPR measurement systems and kits for SPR chip immobilized with RAM IgG is taken out the spectral point-of-care applications. interrogation setup (Figure 3a) and plugged into the smartphone attachment. Mouse IgG solutions at 2. Materials and Methods concentrations ranging from 1.33 nM to 830 nM were injected successively. Intensity changes of individual pixels at three We designed a compact optical system, using a 3D-printed distinct locations on the sensor surface is shown in Figure 3b. apparatus that hosts the LED source, collimator, bandpass Dose-response curve reveals that nanomolar level detection of filter, linear polarizer, beamsplitter plate and an external antibody analyte is achievable within a dynamic range from a imaging lens which can be easily attached to the smartphone few nanomolars to micromolar concentration. (Figure 1). We employed a silver-gold bilayer structure coated on the periodic corrugations of Blu-ray discs in order to perform plasmon resonance imaging at the central region of r~500 nm) under normal incidence illumination in aqueous environment (Figure 2). This allowed the optimal use of the CMOS sensor of the smartphone while maintaining high sensitivity, chemical stability and biological affinity. A microfluidic channel is placed on the bi-metallic layer for controlled plumbing of the liquids. The use of Blu- ray discs and standard metal deposition techniques together with the low-cost microfluidic channel resulted in significant cost-reduction which can allow the system to be used for applications requiring disposable SPR biosensors. Figure 3 Nanomolar level detection of capture of mouse IgG by immobilized layer of RAM IgG. (a) Spectral sensorgram showing the immobilization steps of RAM IgG. (b) Dose- response curve for the capture of mouse IgG.
References [1] B. Turker, H. Guner et al. Lab Chip 11, 282 (2011) [2] B. Kaplan, H. Guner et al. Plasmonics 4, 237 (2009)
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0149
The Synthesis and Characterization of PEI Modified Fe3O4/Au Nanoparticles for Rapid Enumeration of E. coli
Hasan İlhan1*, Üzeyir Doğan2, Hakan Çiftçi3, Uğur Tamer2 and Necdet Sağlam1
1Department of Nanotechnology and Nanomedicine, Hacettepe University, Ankara, 06800, Turkey 2Department of Analytical Chemistry, Faculty of Pharmacy, Gazi University, Ankara, 06330, Turkey 3Department of Chemistry and Chemical Processing Technologies, Kirikkale Vocational High School, Kirikkale University, Kirikkale, 71450, Turkey
*Presenter: [email protected]
1. Abstract: 3. Conclusion Magnetic nanoparticles have been utilized as a powerful We believe that this new immunomagnetic sensing tool in various bioassays and used as solid support platform can be used in many application areas owing to its advantages such as biocompatibility, including food quality, water contamination, clinical stability and immunomagnetic seperation. Modification diagnosis and environmental monitoring due to its of these nanoparticles enable to straightforward attractive advantages such as simple, low-cost, portable conjugation with bacteria or biomolecules of interest and disposable features. [1,2]. Numerous magnetic nanoparticles have been developed as magnetic carriers or separation and 4. References: purification process [3]. Polyethyleneimine (PEI) is a [1] U. Tamer, A. Onay, H. Ciftci, and J. M. Greneche, water soluble cationic polymer consisting of amino and J.Nanopart Res 16, 2624, (2014) imino groups which are expected to adsorb onto the surface of gold coated magnetic nanoparticles [4]. [2] U. Tamer, D. Cetin, Z. Suludere, I. H. Boyaci, and Fe3O4/Au-PEI nanoparticles were synthesized in Y. Elerman, Int. J. Mol. Sci.14, 6223, (2013) aqueous solution and characterized by transmission electron microscopy (TEM), UV-Vis [3] C. Wang, J. Xu, J. Wang, Z. Rong, P. Li, R. Xiao, S. spectrophotometer, zeta potential and particle size Wang, J. Mater. Chem. C, 3, 8684, (2015) distribution. [4] H. Ciftci, E. Alver, F. Celik, A. U. Metin, U. Tamer, 2. Materials and Methods: Microchim acta 183, 1479, (2016) In this study, we report the preparation of magnetic [5] W. Ren, I-H. Cho, Z. Zhou, and J. Irudayaraj, nanoparticle and modification of this nanoparticle Chemcom 52, 4930, (2016) specific to E.coli. This modified magnetic nanoparticle provides immunomagnetic separation and specific [6] D. Kwon, S. Lee, M. M. Ahn and S. Jeon, Analytica detection of the target bacteria. Enzyme substrate is Chimica Acta, 883, 61, (2015) covalently linked between magnetic particle and target bacteria to cleave bond easily using an enzyme. Then, magnetic nanoparticle is cleaved from E. coli in order not to prevent bacteria movement on the test strip. β- casein is a good substrate for this application and yeast enzyme is used for bond cleavage. The amide bonds of β-casein on the magnetic particle-casein-biotin are cleaved by the enzyme to release some or all of the biotin moieties from magnetic particle [5]. The magnetic particles are removed by a magnet, and the target bacteria in the solution can be detected efficiently on the test strips. The target bacterium is also labeled with horseradish peroxidase enzyme to enable colorimetric detection on the test strip. Detection pad is spotted with E. coli antibody, 3,3’,5,5’- tetramethylbenzidine (TMB) and hydrogen peroxide solutions to catch labelled bacteria and observe colored product, respectively [6]. Colorimetric measurements are taken on this spot with a portable CCD camera to construct a calibration curve which enables quantitative analysis.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0150
Detection of Listeria Monocytogenes Using Anisotropic Magnetic Nanoparticle Based Surface Enhanced Raman Spectroscopy Hande Yeğenoğlu1, Hilal Torul2*, Adem Zengin3, Belma Aslım1, Demet Çetin4, Zekiye Suludere1, İsmail Hakkı Boyacı5,6, and Uğur Tamer2 1Department of Biology, Faculty of Art and Science, Gazi University 06500, Ankara, Turkey 2Department of Analytical Chemistry, Faculty of Pharmacy, Gazi University, Etiler, Ankara 06330, Turkey 3Department of Chemical Engineering, Yüzüncü Yıl University, Van 65080, Turkey 4Science Teaching Programme, Gazi Faculty of Education, Gazi University, Besevler, Ankara 06500, Turkey 5Department of Food Engineering, Hacettepe University, Beytepe, Ankara 06800, Turkey 6Food Research Center, Hacettepe University, 06800 Beytepe, Ankara, Turkey *Presenter: [email protected]
1. Introduction
Diseases caused by bacterial pathogens are intense concerns due to occurrence of high death rate in the world [1]. For this reason, detection of bacterial pathogens in food products has an importance. Although there are several detection methods developed for this purpose, these conventional methods usually include microbiological culturing and plating, which are time-consuming due to consist of several enrichment steps. In addition to conventional methods, some different techniques including flow cytometry [2], Figure 1. The decrease of the peak intensity at 1333 cm- 1 enzyme-linked immunosorbent assay (ELISA) [3], and illustrated symmetric NO2 stretching bands of DTNB polymerase chain reaction (PCR) [4] have been at increasing L. monocytogenes concentrations developed. Nevertheless, these techniques have some obtained with magnetic gold nanoparticles; a) no limitations such as sensitivity, specificity, speed, and Listeria monocytogenes , b) 2,2 x 101 cfu/mL, c) 2,2 x cost efficiency. As a result of these limitations, 102 cfu/mL, d) 2,2 x 103 cfu/mL, e) 2,2 x 104 cfu/mL, f) development of a new method is significantly necessary 2,2 x 105 cfu/mL, g) 2,2 x 106 cfu/mL to detect low concentrations of pathogens in different media [5]. In this work, a highly selective and sensitive The SERS response was found to be linear between the concentration of bacteria in range 2,2x101-106 cfu/mL. SERS system was developed for immunomagnetic 2 separation and detection of Listeria monocytogenes in (R : 0.991). milk sample. 2. Experimental References Anisotropic magnetic gold nanoparticles with SERS [1] Yang L. and Bashir R., Biotechnology Advances, active properties were synthesized and used in 2008, 26, 135–150. immunoassay systems. In order to collect L. [2] Kempf V.A.J., Mandle T., Schumacher U., Schafer Monocytogenes bacteria from milk sample, bacteria A. and Autenrieth I. B., Int. J. Med. Microbiol., 2005, were interacted with novel antibody conjugated 295, 47−55. magnetic Fe-Au nanoparticles. Then the collected [3] Dylla B.L., Vetter E.A., Hughes J.G., and Cockerill bacteria were interacted with DTNB labeled gold F.R., J. Clin. Microbiol., 1995, 33, 222−224. nanoparticles to measure amount of Listeria [4] Belgrader P., Benett W., Hadley D., Richards J., monocytogenes in milk sample. Stratton P., Mariella R. and Milanovich F., Science, 3. Result 1999, 284, 449−450. [5] Zhou H., Yang D., Ivleva N.P., Mircescu N.E. and The calibration curve was obtained with the changes of Niessner R., Anal. Chem., 2014, 86, 1525−1533. the peak intensities of NO2 stretching band versus different L. monocytogenes bacteria concentrations.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0146
Synthesis of DNA Aptamer Conjugated Magnetic Graphene Oxide and Its Use As A Photo-thermal Agent for Killing Methicillin-Resistant Staphylococcus Aureus
Ismail Ocsoy1* and Muserref Arslan Ocsoy2
1Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey 2Department of Physics, Faculty of Science, Erciyes University, 38039 Kayseri, Turkey;
*Presenter: [email protected]
The detection and destruction of bacteria is not only Figure 1. Illustration of the binding of Apt@mGO to important for human and animal health but also for MRSA and cell destruction throught PTT industry and crop production security. Staphylococcus aureus (SA) which is the one of the most dangerous disease-causing bacteria exhibits the resistance to various antibiotics. The methicillin resistant staphylococcus aureus (MRSA) is one of the most dangerous pathogenic (disease-causing) bacteria is usually called “superbug”8-10. It The has been high demand to develope alternative and effective approaches rather than using antibiotics in order to efficiently detect or destruct the MRSA.
In this study, a multifunctional nano platform was developed for detection and photothermally destruction of MRSA bacteria. Magnetic GO functionalized with MRSA aptamers was produced for this purpose. First of all, the iron oxide (Fe3O4) nanoparticles (NPs) were grown on the surface of the GO and magnetic GO
(mGO) was functionalized the aptamers modified with Figure 2. Illustration of the suspension and aggregation amin (-NH ) group on one end that were specifically 2 Apt@mGO-MRSA bacteria. synthesized for MRSA. The MRSA bacteria were rapidly, sensitively and accurately captured with aptamer functionalized mGO (Apt@mGO) and it was References photothermally destroyed under the near infrared laser (NIR, 808 nm). While aptamer specifically binds to [1] Lancet. Infect. Dis. 2010, 10, 597–602. MRSA, MRSA were magnetically separated with a [2] Arch Intern Med.1998, 158, 895–899. magnet without centrifugation due to Fe3O4 NPs on the [3] Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 11838– surface of the GO. While GO is used as a platform for 11843. aptamer and Fe3O4 NPs, it is utilized a photothermal [4] ACS Nano, 2013, 7, 8972-8980. agent converting laser light to heat when exposed to 808 [5] RSC Adv. 2016, 6, 30285-30292. nm NIR laser. Also, it is considered that GO tightly [6] ACS Nano, 2013, 7 (2), pp 1281–1290 wraps the MRSA bacteria due its sheet shape and carrying several functional groups on the surface.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0152
The Investigation of DNA Binding Profiles of Gold Nanoparticle Bound Lignan Species Called Lariciresinol Using Spectrophotometry and Spectrofluorimetry
İsmail Murat Palabıyık1*, Nuri Özmen1, Mehmet Gökhan Çağlayan1 and Feyyaz Onur1
1Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University, Ankara,Turkey
*Presenter: [email protected]
1. Introduction Figure 1. Observed spectrums of LARI - β-CD-AuNP with increasing concentrations in dsDNA 0.1 M Owing to both the life style and environmental Na HPO (pH: 7.40) problems; nowadays frequency of prevalence of cancer 2 4 diseases highly increased so far as the past years. Lignans, also called phytoestrogens, are one of the main groups of herbal components. In recent years, in vitro, 400 animal and some epidemiological studies have reported the possibility of lignans to be used in treatment of 300 prostate, breast and colon cancers via antiestrogenic, 200 antiangiogenic, antioxidant and proapoptotic mechanism [1,2]. Intensity(a.u.) 100 2. Scope 0 600 650 700 750 800 Within the scope of studies of this study, connection of Wavelength (nm) lignan species namely lariciresinol to gold nanoparticles Figure 2. Observed florescence spectrums of modified by β-cyclodextrine were achieved and LARI - β-CD-AuNP with increasing in dsDNA interactions of pure and connected form of lariciresinol concentrations in 0.1 M Na HPO (pH: 7.40) with single and double strand DNA were established 2 4 using with spectrophotometric and spectrofluorimetric methods. Table 1. Ksv values for interactions between LARI - β- 3. Results and Conclusion CD-AuNP and dsDNA in different experimental medium In this study, interaction between pure and bounded form of lariciresinol and double strand DNA were Experimental conditions Ksv values investigated in different pH, ionic strength and pH 4.40 0.01 M 1350.50 temperature. In spectrums obtained from NaH2PO4 spectrophotometry, there is an increase in absorbances, pH 7.40 0.01 M 1101.40 batochromic shift in bounded form (Figure 1) and Na HPO hypsochromic shift in pure form. Beside this, an 2 4 pH 8.40 0.01 M 831.32 isosbestic point was observed and binding constant was Na HPO changed in different ionic strength. In 2 4 0.05 M NaCl 1130.60 spectrofluorimetric measurements, a quenching (Figure 0.10 M NaCl 1068.20 2) was observed with increasing in DNA concentrations. 0.20 M NaCl 1078.60 Also, Ksv values are decreased with increasing in temperature (except 313 K). These findings are shown 298 K 969.06 that there is a binding between DNA and lariciresinol 303 K 1278.60 and this binding is occurred both intercalation and 308 K 1522.50 groove binding way [3]. 313 K 1282.70 Acknowledgements: This study was supported by The Scientific and Technological Research Council of Turkey, Grant SBAG-112S591
References [1] Chen, J., Thompson, L.U. Breast Cancer Research and Treatment, 80, 163–70, 2003. [2] Chen, L.H., Fang, J., Sun, Z., Li, H., Wu, Y., Demark- Wahnefried, W., Lin, X. Journal of Nutrition, 139, 653-9, 2009. [3] Sirajuddin, M., Ali, S., Badshah, A. Journal of Photochemistry and Photobiology B Biology, 124, 1 – 19, 2015.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0154
A Novel Hydrogel System for the Wound Healing in the Diabetic Patients
K. A. Usal1,2* and T. Dursun3,4
1 Department of Cognitive Science, Middle East Technical University 2 Department of Research and Development, İleri Biyotek Biomedical R&D Company, 3 Department of Biotechnology, Middle East Technical University 4 Department of Biological Sciences, Middle East Technical University
*Presenter: [email protected]
1. Introduction of the EGF-loaded GELMA hydrogels will be performed. At the end, a growth factor loaded hydrogel Wound healing is a specific biological process related to system will be produced for the use of diabetic patient’s the general phenomenon of growth and tissue wounds. regeneration [1]. It includes a series of interdependent and overlapping stages in which a variety of cellular and matrix components act together to reestablish the integrity of damaged tissue and replacement of lost tissue [2]. Diabetic patients have severe problems in the wound healing process due to the damaged blood flow to the required areas [3]. Therefore, any minor scar can turn into ulcers in the extremities, especially feet. If these scars are not treated, these problematic wounds would cause amputation. Nowadays, general wound cleaning procedures are applied to treat the patients, however, these treatments are not enough to provide a complete healing. Hydrogels contain significant amounts of water (70- Figure 1 Synthesis of methacrylated gelatin. Gelatin 90%) and possess most of the desirable characteristics macromers containing primary amine groups were reacted of an ‘ideal dressing’ [4]. Experimental studies in with methacrylic anhydride (MA) to add methacrylate pendant animals have demonstrated that the topical application groups (A). To create a hydrogel network, the methacrylated of epidermal growth factor accelerates the rate of gelatin was crosslinked using UV irradiation in the presence epidermal regeneration of partial-thickness wounds and of a photoinitiator (B) Taken from Khademhosseini et al., second-degree burns [5]. In this study, a hydrogel 2010 [6]. loaded with epidermal growth factor (EGF) will be produced to improve the healing process in the diabetic patients. This hydrogel system can also be used in any References type of wound to provide a faster and improved healing [1] Boateng, J. S., Matthews, K. H., Stevens, H. N., & process. Eccleston, G. M. (2008). Wound healing dressings and 2. Materials and Method drug delivery systems: a review. Journal of pharmaceutical sciences, 97(8), 2892-2923. Hydrogel was composed of methacrylated gelatin. [2] Rothe M, Falanga V. 1989. Growth factors, their biology Therefore, methacrylation of gelatin was done. gelatin and promise in dermatologic disease and tissue was dissolved in water and methacrylic anhydride (3%, repair. Arch Dermatol125: 1390–1398. v/v) was added dropwise, and the reaction run for 2 h at [3] Moura, L. I., Dias, A. M., Carvalho, E., & de Sousa, H. C. 50˚C. The solution was dialyzed against distilled water. (2013). Recent advances on the development of wound Methacrylated gelatin (GELMA) obtained was dried dressings for diabetic foot ulcer treatment-A review. Acta biomaterialia, 9(7), 7093-7114. with lyophilisation and stored at 4˚C. Crosslinking of GELMA hydrogel was achieved with UV exposure (at [4] Morgan DA. 1999. Wound management products 365 nm) (Figure 1). in the drug tariff. Pharm J 263:820–825. 3. Results and Discussion [5] Brown, G. L., Nanney, L. B., Griffen, J., Cramer, A. B., Characterization studies showed that these GELMA Yancey, J. M., Curtsinger III, L. J., ... & Lynch, J. B. (1989). hydrogels have appropriate pore size (100 (µm) and Enhancement of wound healing by topical treatment with porosity (75%) for the cell attachment and the epidermal growth factor. New England Journal of proliferation studies. Water content of the GELMA Medicine, 321(2), 76-79. hydrogels was found as 95% (w/w). Therefore, it can be classified as high water content hydrogel and its [6] Nichol, J. W., Koshy, S. T., Bae, H., Hwang, C. M., biocompatibility is expected to be high. Yamanlar, S., & Khademhosseini, A. (2010). Cell-laden microengineered gelatin methacrylate hydrogels. Biomaterials, 31(21), 5536-5544. After the characterization studies, in vitro performances 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0155
Adsorptive stripping determination of Ezetimibe in pharmaceutical dosage forms and biological fluids
L. Karadurmus1,2*, S. Kurbanoglu2, B. Uslu2 and S.A. Ozkan2
1 Adıyaman University, Faculty of Pharmacy, Department of Analytical Chemistry, Adıyaman Turkey 2 Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, Ankara, Turkey
*Presenter: [email protected]
1. Introduction maximum current was observed in the pH 0.3 sulfuric acid medium. As a result of scan rate studies, in the pH Electroanalytical methods emerge with the interplay 0.3 sulfuric acid medium, the electrochemical behavior between electricity and chemistry; in other words they of ezetimibe was found adsorption-controlled. From the were used to measure electrical quantities, such as relation between E and logarithm of scan rate, current, potential, or charge and their relationship with p E =Eo+(2.303.RT/ά.n.F)logv n was calculated as 2.38. the chemical parameters. These methods are widely p Since ά is accepted as 0.5 for irreversible systems. The used in fields like environmental monitoring, industrial peak potential was shifted to more negative values with quality control or biomedical analysis [1]. Another field increasing pH. From the slope of the equation Log (I ) = in which electrochemical methods are extensively used p 0.78 log v – 1.19 (r=0.998) it can be resulted that the is drug analysis and these methods have proved to be reaction is adsorption controlled since the slope is close highly sensitive due to the straight forwardness, low to 1. The E –pH equation of ezetimibe; E =998.49- cost and relatively short analysis time [2]. p p 50.99 pH indicates that equal numbers of protons and
electrons are involved in the electrode reaction at GCE. Glassy carbon electrode (GCE) is the most common carbon-based electrode because of its excellent Under optimized deposition time and potential mechanical and electrical properties, wide potential conditions using adsorptive stripping differential pulse range, chemically inert nature and impermeability to voltammetric technique Ezetimibe was determined gases. They are easily mounted, polishable and concentration from 1x10-6 M to 2.5x10-5 M with a limit compatible with all common solvents. They allow many of detection as 0.32 nM and limit of quantification as 1 applications in many different areas, since their nM. In optimized conditions, Ezetimibe determination performances are relatively reproducible. Ezetimibe was achieved in human urine, and human serum. For the ((3R,4S)-1-(4-fluorophenyl)-3-[(3S)-3- (4-fluorophenyl) validation of the proposed methods, precision and -3-hydroxyl propyl)] -4-(4-hydroxy phenyl)-2- accuracy were examined by assaying five replicate azetidinone) is a drug that inhibits cholesterol samples as individual days (within day) and absorption from the small intestine, which was intermediate precision (between days). Relative approved by the US Food and Drug Administration for standard deviations (RSD %) and bias % were the treatment of primary hypercholesterolemia [3,4]. calculated to check the precision of the method. After 2. Experimental statistical evaluation the results indicate that method is Voltammetric measurements were recorded using BAS analytically acceptable from the view point of precision 100 W (Bioanalytical System, USA), electrochemical [5]. analyzer with a standard three-electrode configuration. The three electrode system consisted of a GCE (BAS: Ф References = 3 mm, diameter) as working electrode, a platinum [1] J. Wang, “Analytical Electrochemistry”, Wiley-Vch, wire counter electrode, and an Ag/AgCl saturated KCl New Jersey, 2006. reference electrode. GCE was polished manually with [2] S.A. Ozkan, “Electroanalytical methods in aqueous slurry of alumina powder (Ф = 0.01 μm) on a pharmaceutical analysis and their validation”, HNB damp smooth polishing cloth (BAS velvet polishing Pub., New York, 2011. pad) just before each measurement. All measurements [3] L. L. Brunton, “Goodman and Gilman’s: The were achieved at room temperature. pharmacological basis of therapeutics”, McGraw Hill In this study, the electrochemical behavior of Ezetimibe Press, New York, 2010. was investigated using adsorptive stripping differential [4] S. C. Sweetman, “Martindale: The Extra pulse voltammetric method. Pharmacopoeia”, 35th edition. Pharmaceutical Press, 3. Results London, 2007. The electrochemical behavior of Ezetimibe was [5] J. Ermer and J. H. Miller, “Method Validation in investigated with in a wide pH range (pH 0.3-7.0) using Pharmaceutical Analysis”, Wiley-VCH, Weinheim, adsorptive stripping differential pulse voltammetric 2005. technique at glassy carbon electrode. With adsorptive stripping differential pulse voltammetric technique,
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0201
A Paper-based Platform for Optical Sensing of Dopamine by Graphene Quantum Dots
M. Esad Sağlam1*, Aylin Arıcı1, Ilker Akin2, Erhan Zor3 and Haluk Bingol4
1 Institute of Science, Necmettin Erbakan University, Konya, Turkey 2 Department of Chemistry, Selçuk University, Konya, Turkey 3 Department of Science Education, Necmettin Erbakan University, Konya, Turkey 4 Department of Chemistry Education, Necmettin Erbakan University, Konya, Turkey
*Presenter: [email protected]
Abstract excitation independent PL behavior. On excitation of the Dopamine (DA) given in Figure 1 is one of the most absorption band of 470 nm, the PL spectrum of GQDs influential neurotransmitter in mammalian central exhibits a highest peak at 580 nm with a Stokes shift of nervous system. Thus, its detection is very crucial for 110 nm as can be seen in Figure 2. The fluorescence the diagnoses, monitoring and treatments of several intensity of the GQDs in aqueous media turned out to neurological disorders such as Schizophrenia and decrease sensitively when interacted with DA molecules Parkinson’s disease. Different analytical methods have (the inset of Fig. 3). It displayed the fluorescence been reported for DA determination, such as change as a function of the concentration of DA from chromatography combined with mass spectrometry, 6.0 µM to 120.0 µM in harmony with the literature [5]. optical and electrochemical techniques [1]. Although the The charge transfer between GQDs and DA molecules methods can reach very low detection limits, the linked by hydrogen bonding and electrostatic interaction procedures require not only sample pretreatment, was suggested to be responsible for the fluorescence lengthy analysis times and high costs. quenching of the GQDs.
Figure 1 Structure of DA
In the recent years, many researchers have focused on optical and electrochemical paper-based sensors which are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices [2]. Figure 2 The fluorescence excitation and emission spectra of In fabricating paper-based sensors, the choice of the GQDs dispersed in water materials that meet the criteria of simplicity and efficient production process need to be considered. There are different optical materials involving simple organic molecules, nanoparticle and quantum dots that could be used to tune the optical and sensing properties of the paper-based sensor. Graphene quantum dots (GQDs), as a class of fluorescent probes, have attracted considerable attention in recent years. Compared with metal based quantum dots, GQDs have high photo- stability, low toxicity, simple synthesis ways as well as tunable fluorescence emission properties, which gained Figure 3 The fluorescence sensing of DA by commercial them increased attention in a variety of applications [3]. paper embedded GQDs. Herein, we report a novel, low cost, disposable, rapid and straightforward paper-based platform embedded Figure 3 demonstrates the fluorogenic detection of DA photoluminescent GQDs for optical sensing of DA in using GQDs on the commercial paper. Once the paper- aqueous media. GQDs was prepared by top-down based sensor was fabricated, the DA solution was synthesis based on acidic oxidation cutting of graphene dropped onto the loading zone. The PL quenching oxide (GO) following the literature [4]: GO firstly showed the presence of DA in aqueous media. synthesized using the improved Hummers method was Acknowledgement: The authors are grateful to the Scientific re-oxidized in HNO3 for 20 h at 90˚C. The mixture was Research Projects of Necmettin Erbakan University further dialyzed in a dialysis bag (MWCO: 2 kDa). The (161310004) for financial support. GQDs were characterized by FT-IR, Raman, XPS and TEM. The water-soluble fluorescent GQDs is References [1] Polo, E. and Kruss S. Anal Bioanal Chem. 408 (2016), 2727-41. transferred onto a commercial paper for “yes/no” type [2] Liana D.D. et al., Sensors, 24 (2012), 11505-26. optical sensing of DA by spotting and then dried to [3] Zheng X.T. et al., Small, 11 (2015), 1620–1636. [4] Fan L. et al., Talanta, 101 (2012), 192–197. remove the solvent. The orange emitting GQDs exhibit [5] Zhao et al., Sensors & Actuators, B: Chemical, 223 (2016), 246-251. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0202
Electropolymerized Films of 1,3-Bis(2-pyridylimino)isoindolato-palladium Complex: Biosensor Applications
Metin Ak1, Tuğba Soğancı1, Tuğçe Yazıcı Tekbaşoğlu2, Atıf Koca3 and M. Kasım Şener2*
1 Department of Chemistry, Pamukkale University, 20017 Denizli, Turkey 2 Department of Chemistry, Yıldız Technical University, 34210 İstanbul, Turkey 3 Department of Chemical Engineering, Marmara University, 34722 İstanbul, Turkey
*Presenter: [email protected]
1. Introduction proposed sensor showed a linear amperometric response for glucose within a concentration range of 0.25 mM to The chemistry of isoindolines has been the key for the 2.5 mM (LOD: 0.176 mM). Amperometric signals at 1 development of phthalocyanines as well as related mM of glucose were 17.9 μA under anaerobic macrocycles and chelating ligands [1]. Among the conditions. Amperometric signals of the P(EDOT- isoindoline-based chelating ligands, bis(2- PdBPI-co-HKCN)/GOx electrode decreased by 13% pyridylimino)isoindolines (BPI) have been the focus of within eight week. The P(EDOT-PdBPI-co- interest because they are readily synthesized and easily HKCN)/GOx electrode showed excellent selectivity in modified. [2]. Most of the published papers about bis(2- the presence of ethanol and phenol. This result shows pyridylimino)isoindolines and their metal complexes that, modification of the proposed sensor by glucose focused on structural characterization and main oxidase led to the fabrication of a glucose biosensor application areas of these compounds are homogeneous with excellent performance (Figure 2). catalysis and biomimetics [3]. Here, we present first time a new bis(2-pyridylimino)isoindolato-palladium complex bearing electropolymerizable EDOT (3,4- (ethylenedioxy)thiophene) substituent and show it may be used for glucose sensing as heterogeneous catalytic system. 2. Experimental Monomer palladium complex EDOT-PdBPI was synthesized from EDOT-BPI [4] (Figure 1). Polymerization of synthesized monomer and copolymerization with HKCN [5] were carried out by an electrochemical method. In addition to all of these, a simply fabricated amperometric glucose sensor based on glucose oxidase (GOx), P(EDOT-PdBPI-co-HKCN) modified graphite rod electrode was improved. Figure 2. Amperometric biosensor response of Cl P(HKCN)/GOx, P(EDOT-PdBPI)/GOx, N N N Pd N P(EDOT-PdBPI-co-HKCN)/GOx H N N N N N N Acknowledgments: This work was supported by N S S TÜBİTAK (Project Number: 115Z555). O O NH O O O O O References [1] I-S. Tamgho, J. T. Engle, C. J. Ziegler, Tetrahedron Lett., 2013, NH2 S S 54, 6114-6117. EDOT-BPI EDOT-PdBPI HKCN [2] M. K. Şener, U. Avcıata, J. Chem. Research, 2007, 3, 138-140. Figure 1. Structural formulas of monomers 3. Results and Discussion [3] R. Csonka, G. Speier, J. Kaizer, RSC Adv., 2015, 5, 18401-18419. In our matrix, amino groups which are arising from the [4] M. K. Şener, T. Yazıcı, A. Koca, 18. JCF-Frühjahrssymposium, Book of Posters, 2016, 222. HKCN were used for the enzyme immobilization. On the other hand, the presence of EDOT-PdBPI serves an [5] H. C. Söyleyici, M. Ak, Y. Şahin, D. O. Demirkol, S. Timur, extra electron by reason of the oxidation of H2O2 to O2. Mater. Chem. Phys., 2013, 142, 303-310. Amperometric detection was carried out following oxygen consumption at -0.7 V vs. the Ag reference electrode in phosphate buffer (50 mM, pH 6.0). The 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0203
Graphene/nafion nanocomposite based electrochemical biosensor for detecting Hypoxanthine
M.Kurtulgu1,2* and S.Çete3
1Institue of Natural Sciences, University of Gazi/ 2Department of Basic Science, Turkish Military Academy 3Department of Chemistry, Gazi University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction 3. Conclusion Graphene (GR), emerging as a true two-dimensional There are many reports regarding the electro catalytic material, has received increasing attention due to its activity of graphene based sensors for the applications unique physicochemical properties such as high surface of H2O2. Some of them are listed in Table1. In our study 2 -1 area (2630 m g ), excellent conductivity (200.000 xanthine biosensor based on immobilization of XO in Pt 2 -1 -1 cm V s for single layer), high mechanical strength, nanoparticles/ graphene/ nafion nanocomposite film is and ease of functionalization and mass production. [1] responsive to a low concentration of H2O2 (~5µM) and Xanthine mainly act to oppose the actions of the two different linear determination ranges of 10-5-10-4 M sleepiness-inducing adenosine, and increase alertness in and 10-3-10-1 M with R2= 0,999 and R2= 0,967 the central nervous system. They also stimulate the respectively. According to literature our sensor has low respiratory center, and are used for treatment of infantile detection limit and long linear range among to other apnea. Due to widespread effects, the therapeutic range studies with good R2 values. This property shows us our of xanthine’s is narrow, making them merely a second- sensor is good candidates for biosensor applications. line asthma treatment. Also increasing the amount of xanthine in tissue increases the risk of heart attack. [2] Table–1 Comparison of the performance of H2O2 sensor The therapeutic level is 10-20 micrograms/mL blood; Potential Limit of signs of toxicity include tremor, nausea, nervousness, Linear range Ref. (V) detection and tachycardia/ arrhythmia. Also hypoxanthine is an critical metabolite of adenine nucleotide degradation, −0.3 100 μM to 100 mM 31.3 μM [7] which is mainly accumulated in biological tissues .[3] The level of hypoxanthine is used in the food industry −0.3 0.10–50 mM 4 μM [8] for evaluating the freshness of fish. So, the determination of hypoxanthine has considerable −0.05 20 μM to 0.2 mM 1.9 μM [9] importance for quality control of fish and other −0.4 20 μM to 6.25 mM 2.5 μM [10] products in the food industry.[4] −0.4 20 μM to 2.1 mM 9.4 μM [11] 2. Experimental Details I.10 μM to 100 μM This +0.6 5 μM work II.1 mM to 100 mM
The synthesis of graphene from graphite was performed References according to the method of Hummer with some [1] Yuyan Shao, Jun Wang, Hong Wu, Jun Liu, Ilhan A. Aksay, Yuehe Lin, modifications. [5] GR/PtNPs was synthesized from Electroanalysis 2010, 22, No. 10, 1027 – 1036 graphene oxide using single-step reduction method with [2] Bhagavan N.V, Xanthine oxidase reaction Medical Biochemistry,652- 654,1990. some modifications. [6] The quantification of xanthine [3] Zhang , J. ; Lei , J. ; Pan , R. ; Xue , Y. ; Ju , H. Biosens. Bioelectron. 2010 , can be achieved via electrochemical detection of the 26 , 371 . [4] Hernandez-Cazares , A. S. ; Aristoy , M. C. ; Toldra , F. Food Chem. 2010 , enzymatically released H2O2. The immobilization of 123 , 949 . xanthine oxidase (XO) has been achieved by cross- [5] W.S.Hummers, R.E.Offeman, Preperation of graphitic oxide, linking with glutaraldehyde. The performances of the J.am.Chem.Soc.80 (1958) 1339 [6] G. Zhiguo, Y. Shuping, L. Zaijun, S. Xiulan, W. Guangli, F. Yinjun, L. biosensor have been investigated by electrochemical Junkang. Chim. Acta, 701 (2011), p. 75 method at an optimum potential of +0.6 V in pH 8.0 [7] S. Liu, J.Q. Tian, L. Wang, X.P. Sun. Carbon, 49 (2011), p. 3158 [8] R. Ning, W.B. Lua, Y.W. Zhang, X.Y. Qin, Y.L. Luo, J.M. Hu, A.M. Asiri, phosphate buffer. All the electrochemical measurements A.O. Al-Youbi, X.P. Sun Electrochimica Acta, 60 (2012) were performed with a conventional three-electrode [9] E. Jin, X.F. Lu, L.L. Cui, D.M. Chao, C. Wang Electrochimica Acta, 55 (2010), p. 7230 system. [10] X.X. Liu, H. Zhu, X.R. Yang Talanta, 87 (2011), p. 243 [11] S. Woo, Y.R. Kim, T.D. Chung, Y. Piao, H. Kim Electrochimica Acta, 59 (2012), p. 509
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0139
Layer-by-layer Films of Polydopamine and Gold Nanoparticles
G. Bakirci Dündar1, M. Yilmaz1,2* and Gokhan Demirel1
1Bio-inspired Materials Research Laboratory (BIMREL), Department of Chemistry, Gazi University 2 Department of Bioengineering, Sinop University
* Presenter: Introduction of multilayer films lead to obvious red-shifting and broadening, along with increased absorbances due to Many practical applications of coinage metal collective SPR characteristics of AuNP-containing nanoparticles strongly depend on their optical multilayer films with a proper interparticle distance. properties, arising from localized surface plasmon resonances (SPRs). The SPRs can be tuned by varying parameters such as size and shape of nanoparticles, dielectric environment (refractive index of medium/solvent and of coating shells), and interparticle distance. Recently, the layer-by-layer (LbL) technique has been proposed as a versatile, easy, and inexpensive bottom-up nanofabrication technique for the preparation of nanoparticle-containing ultrathin multilayer films. By employing this technique, individual and collective SPRs can be created from intralayer or interlayer interparticle interactions. However, in most cases the LbL technique usually necessitates the deposition of oppositely charged polyelectrolytes on substrates. This issue leads to complicated and time-consuming process, limiting their use in practical applications.In this study, to overcome the major drawbacks of nanoparticle- containing LbL thin films, we proposed gold Figure 1 Top and cross-section SEM micrographs of nanoparticle-containing (AuNP) films of polydopamine (PDOP/AuNP)n LbL films for different layer (n) numbers: n . (PDOP) through oxidative polymerization of dopamine. 1 (a, d), n . 2 (b, e) and n . 3 (c, f), and UV-visible absorption Seminal work by Messersmith and co-workers depicted spectra of (PDOP/AuNP)n LbL thin films (g) [3]. that PDOP can bedeposited on almost all types of inorganic and organic substrates with easily controllable In SERS studies (Fig. 2), for the multilayer thickness, robust stability, and excellent (PDOP/AuNP)2 and (PDOP/AuNP)3 films, additional biocompatibility and as a result of its functional groups SERS enhancement was observed compared to the including catechol, amine and imine, metallic single layer film ((PDOP/AuNP)1). In those cases, the nanoparticles may be easily formed in situ in a collective SPR between nanoparticles within adjacent controlled manner without the use of any additional layers was mainly responsible for the generation of hot reductants or metallic seed particles [1]. To this end, the spots with extremely high electric field enhancement. substrates were immersed sequentially into dopamine (2 mg/ml in Tris-buffer) and chloroauric acid (0.1 mg/ml) solutions until the creation of desired multilayer films. Surface enhanced Raman spectroscopy (SERS) of the relevant films were investigated in detail.
2. Results and Discussion
According to our previous study, we set the PDOP deposition time as 3 h to form an approximately 10 nm- Figure 2 (a) Representative SERS spectra of methylene blue thick layer and 12 h for the in situ growth of AuNPs [2]. (MB) on the (PDOP/NP)n LbL thin films with different layer As shown in Fig. 1, it is observed that the density and (n) numbers (n . 1, n . 2, and n . 3) and (b) reproducibility of SERS spectra of MB collected on 30 randomly selected spots average size of the deposited AuNPs were dramatically of (PDOP/AuNP) LbL thin films [3]. changed with the number of layers. When the number 3 of layers increased in the fabricated films, the size of the References AuNPs also increased, and average particle size ranged [1] Lee et al. Science, 2007, 318, 426–430. from 30 nm to 110 nm for the (PDOP/AuNP)2 film and from 40 nm to 120 nm for the (PDOP/AuNP)3 film. In [2] Akin et al. J. Mater. Chem. B, 2014, 2, 4894–4900. UV-vis spectra of films strong absorption peak maxima were found in the range of 532–572 nm. The emergence [3] Yilmaz et al. RSC Adv., 2016, 6, 12638–12641. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0205
Rosmarinic acid modified screen-printed electrode for NADH sensor
M. Bilgi1,2, E.M. Sahin2* and E. Ayranci2
1 Department of Chemistry, Çankırı Karatekin University, Çankırı, Turkey 2 Department of Chemistry, Akdeniz University, Antalya, Turkey
*Presenter: [email protected]
Abstract 25 Rosmarinic acid (RA) is a hydroxycinnamic acid derivative and a naturally occurring phenylpropanoid 15
that is commonly found in species of the Boraginaceae family, the subfamily Nepetoideae of the Lamiaceae 5 family, and in lower plants such as ferns and hornworts. The antioxidants are redox agents, and both -5 electrochemical and chemical oxidations of these Current/µA compounds have been studied [1]. Dehydrogenase -15 based biosensor need nicotinamide adenine dinucleotide -0,1 0,1 0,3 0,5 Potential/V (NAD+) as a coenzyme. Reduced form NADH Figure 1. CVs obtained with SPCE/RA at a generated in the enzymatic reaction is oxidizing on the -1 electrode surface at suitable potantial and scan rate of 50 mV s in 50 mM pH 7.0 PBS electrooxidation of NADH is detected. Electrooxidation (in 0.1 M KCl) containing no NADH (inner of NADH at high overvoltage causes irreversible CV) and containing 1 mM NADH (outer CV) formation of enzymatically inactive forms of NAD+ and contamination (fouling) of electrode surface due to 40 adsorption of these products which results in background currents leading to interferences in real 30 samples. In order to decrease the high overpotential and to minimize the side reactions, various mediators, 20 polymers and nanomaterials (NMs) have been widely used in modification of electrodes [2]. The main aim of 10 the present research is used by RA as new redox 0 material to the electrooxidation of NADH at lower Current/µA potential. As the sensor application of RA modified -10 SPCE is utilized determination of NADH. -0,1 0,1 0,3 0,5 Potential/V RA was deposited on SPCE by potential cycling Figure 2. Dependence of CVs response on between -0.1 to +0.8 V for 5 cycles in at a scan rate of NADH concentration for a SPCE/RA in in 50 20 mV s-1 a solution containing 1 mM RA, 50 mM pH mM pH 7.0 PBS (in 0.1 M KCl) at 50 mV s-1. 7.0 PBS. Figure 1 represents the cyclic voltammograms NADH concentrations are 0.1, 0.25, 0.50,0.75, of 1 mM NADH and buffer obtained with SPCE/RA. 1.0, 1.5, 2.0, 3.0, 5.0 mM from inner to outer The cyclic voltammograms were obtained in a series of cycles, respectively. concentrations of NADH and are given in Figure 2. The anodic current was an enhancement with the addition of References NADH. NADH was detected amperometrically by applying a potential of +0.25 V (vs. Ag pseudo [1] Park, S.U.; Uddin, M.R.; Xu, H.; Kim, Y.K.; Lee, reference electrode). Measured current plotted vs S.Y.; Afr. J. Biotechnol., 2008, 7, 4959-4965. NADH concentration gave a sensitivity and a [2] Sahin, M.; Ayranci, E., Electrochimica Acta 166 correlation coefficient of 8.82 μA.mM-1 and 0.991, (2015) 261–270. respectively.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0207
The Comparison of the Development and Performance of The Biosensor For Determination of Aminoglycoside Antibiotics In Animal Products On The Ultrasensitive Aptamer Based Biosensor
Mert Muhammed Koc1*, Merve Kucukoflaz1, Yagmur Guler1, Şengül Kurtuluş and Mustafa Oguzhan Caglayan1
1Nanotechnology Engineering Department, Cumhuriyet University, Sivas, Turkey
*Presenter: [email protected]
1. Introduction two different paths immobilization. Silicon flakes and Antibiotics bacteria are chemical compounds that kill or gold coated glass slide surface immobilization methods slow their growth and are useful in treating bacterial of the specified aptamer groups on the optimized obtain infections. But it consist of a danger as the development this study, the target, the other can compete with of resistant bacteria against that antibiotic use excessive antibiotics residual analysis techniques and the or unnecessary use of the drug, Taken together with development of an unlabeled detection methods. residual nutrients consumed through the food chain Kanamycin or neomycin using such study presented on antibiotics, super bacteria to form and cause damage to the spectroscopic ellipsometry and ellipsometry sincere organs such as the liver and kidney. Therefore, exact reflection of two different types of sensors have monitoring of residual levels of antibiotics in the food been developed and compared. Such study used all chain is important is also a necessity. Also, aptamers and SE with SPRe - TIRE sensors are nearly aminoglycoside antibiotics are ototoxic in terms of gave similar analytical results. Determination of the human health and nephrotoxic. Therefore, environ lowest limit of the kanamycin on the 100 pM, the mental monitoring of antibiotic levels including food highests interest of 4.00 nM, all sensors in the waste, will reduce the risk of forming dangerous multi- determination of possible limit there has been between 1 drug resistant strains of bacteria. uM. for neomycin lowest LOD 360 pM, the highest 2. Materials and Methods has be 6.88 nM. Aminoglycoside antibiotics are ototoxic in terms of human health and nephrotoxic. Therefore also including Table 1 selectivity of the sensor (For SE) your food remnants, the environ mental monitoring of antibiotic levels will reduce the risk of developing drug- Sensor Response (Δ) resistant bacteria at multivariate dangerous species. İn Aptamer Tobramycin Tobramycin Tobramycin many countries in terms of contamination with (not avaible) (available) (purely) antibiotics, such as kanamycin and neomycin, are AntiKnm3 4.3068±0.057 4.6083±0.087 0.3015±0.100 controlled foods of animal origin. The limit until they AntiNeo5 4.8776±0.087 5.0727±0.131 0.4389±0.116 are admitted, on the kanamycin 150ng/ml, and streptomycin for 500ng/ml, and neomycin for 500ng/ml. Therefore, the animal source of the determination of Table 2 selectivity of the sensor (For SPRe-TIRE) antibiotic residues in foods on the new method are targeted to improve access. Due to the high affinity of Sensor Response (Δ) the aptamers show, kanamycin and neomycin, based on Aptamer Tobramyci Tobramyci Tobramycin the aptamer and spectroscopic ellipsometry (SE) and n (not n (purely) fortified by surface plasmon resonance - sincere avaible) (available) biosensor was developed using the methods of the full AntiKnm 7.4985±0.0 8.5337±0.13 0.2481±0.09 reflection ellipsometry (SPRe-TIRE). Quite different 1 70 4 2 from each other on the use of specified methods to AntiNeo1 6.49622±0. 8.6066±0.22 0.60660±0.1 optimize both the immobilization has been carried out 134 9 48 of route conditions. It should be noted, the connection of the sensor 3. Result and Discussion structure must be a straight answer measure. Therefore In this study, toxic effects should both be in the food offered ranges, are expressed as a range measure. The chain due to the accumulation and transfer super- result between the detection limit of the working range, bacteria that can cause it to form aminoglycoside groups the lowest detection limits obtained in this study, are apta-sensor been implemented with the appointment working in a relatively narrow range of enumeration. of two antibiotics. Aptasensor target is measured can be Obtained sensor performance, although kanamycin and converted to form the actual phisicochemical caught neomycin the under limit of the (500ng/ml) wich after the change has been preferred on the ellipsometry designated the clipboard, at the same time, kanamycin which will be used as a converter. Ellipsometric round and neomycin on reported ELİSA method based, of two different techniques, spectroscopic ellipsometry when compared (respctively 0.83ng/mL and 2.73ng and sincere exact reflection (TIRE) are /mL) are compared inside limits. compared. When used because the techniques are slightly different from the sensor surface were followed 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0208
Investigation of the use of Periodic Nanobump Surfaces for Detecting Myoglobin Protein
Merve Çelik1*, Sevde Altuntaş1 and Fatih Büyükserin2
1 Biomedical Engineering Graduate Program, TOBB University of Economics and Technology, Ankara, Turkey 2 Department of Biomedical Engineering, TOBB University of Economics and Technology, Ankara, Turkey
*Presenter: [email protected]
Abstract the membrane is used as the SERS platform. Then this barrier side will be treated with acidic solutions to form Acute myocardial infarction is the most common cause crater on the surface to create a different surface of mortality worldwide.[1] Because of the difficulties of topography with potentially enhanced SERS signals as distinguishing the physical symptoms and the need for predicted with previous simulations. urgent medical intervention, early diagnosis of this disease is crucial. Apart from the physical symptoms of acute myocardial infarction, abnormalities in the ST segment of electrocardiogram of the patient and the concentration of some proteins like myoglobin which starts to be secreted 1 hour after the symptoms and troponin which starts to be secreted 3-6 hours after the symptoms is the markers of this disease.[2] Current protein detection methods like ELISA and [3] electrophoresis are high-cost and requires expertise. It Figure 1 SEM images of the produced images is crucial to design a simple and ultra sensitive protein nanobumpy array(left), nano crater array detection method for early diagnosis in order to increase (right) the survival rate of the patients and overcome the problems mentioned. The prepared surfaces will be modified with Au and the Surface-enhanced Raman spectroscopy (SERS) is a Raman-active dye, Rhodamine 6G. SERS signal powerful technique used for molecular analysis that enhancements of the surfaces will be determined. In the provides molecular fingerprint information and has the last part of this study protein detection will be potential to detect down to single molecule.[4] Despite performed with the surface that has the highest signal the ultra sensitivity and specificity of this technique, enhancement. As the earliest biomarker of acute SERS can not be used as a routine sensing tool.[5] This myocardial infarction, in order to achieve early is because of the poor reproducibility of SERS signals. diagnosis myoglobin will be detected on this biosensing In order to provide highly reproducible SERS signals, platform. reproducible strong SERS-active substrates should be designed. References Properties of an ideal SERS substrate are stated in [5] [1] Straface, Angela L., et al. "A rapid point-of-care cardiac previous researches. The most important properties marker testing strategy facilitates the rapid diagnosis and are high signal enhancement and signal reproducibility management of chest pain patients in the emergency which periodic nanostructured arrays satisfy. In the department." American journal of clinical pathology 129.5 current studies these periodic nanostructures are usually (2008): 788-795. created by lithography.[6] But this technique is time [2] Newby, L. Kristin, et al. "Value of serial troponin T consuming, high cost and can not be applied to large measures for early and late risk stratification in patients with surface areas. acute coronary syndromes." Circulation 98.18 (1998): 1853- 1859. In the proposed system, nanostructured anodic [3] Sharma, Vikash, et al. "Electrochemical impedance aluminum oxide (AAO) membranes are used for SERS immunosensor for the detection of cardiac biomarker signal enhancement. These membranes are a class of Myogobin (Mb) in aqueous solution." Thin Solid Films 519.3 special biomaterials that are produced from high purity (2010): 1167-1170. aluminum via two step anodization methods. The [4] Choi, Dukhyun, et al. "Self Organized Hexagonal production of the substrates are easy and highly Nanopore SERS Array." Small 6.16 (2010): 1741-1744. controllable with this method and compared to [5] Cialla, Dana, et al. "Surface-enhanced Raman spectroscopy (SERS): progress and trends." Analytical and lithography it is cost-effective. It is possible with this bioanalytical chemistry 403.1 (2012): 27-54. procedure to produce AAO membranes with different [6] Banholzer, Matthew J., et al. "Rationally designed column structures and thicknesses depending on voltage nanostructures for surface-enhanced Raman spectroscopy." and anodization time. The produced membranes are Chemical Society Reviews 37.5 (2008): 885-897. used aluminum-free and the nanobumpy barrier side of 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0209
Determination of Spread-Based Biosensor TIRE Multiprecision micropatterned, and Development of Oligonucleotide and Protein Immobilization Method for Chip and the Sensor Performance
Merve Kucukoflaz1*, Mert Muhammed Koc1 , Şengül Kurtuluş1 ,Yagmur Guler1 and Mustafa Oguzhan Caglayan1
1Nanotechnology Engineering Department, Cumhuriyet University, Sivas, Turkey
* Presenter: [email protected]
1. Introduction certain conditions. Bio-molecular determination was Biosensors provide reliable and quick response analysis realized in a short time and with small concentrations of achieved with the combination of appropriate target; by using the advantages of SPRe-TIRE transducers and utilization of selectivity and specifity of phenomena and detection limit decrement using bioaffinity. However, it is required, the reactions those appropriate sensor chip design giving SPR. are fast and selective, occuring on biosensors, to be defined quickly with the same accuracy. Surface 3. Results and Discussion plasmon resonance (SPR) and ellipsometry based on In this study, avian influenza (bird flu) Influenza A optical transducers provide an accurate and an on-line group pathogen assay for the gradual immobilization analysis. In this study, development of a micro- techniques of a sensor that can run as simultaneous patterned biosensor system available for multiple and protein sensor with synthetic ODN-based sensor qualitative/quantitative determination of one or more micropattern that eseasl array (array) structure has been bio-molecules with a single and modified biosensor chip developed. which implements both of total internal reflection ellipsometry and surface plasmon resonance techniques was aimed. 2. Materials and Methods In the first step, a multiple step micro-patterning was applied on designed biosensor chip, then, self assembled monolayer was formed by using various chemical methods on micro-patterned biosensor chip, and finally by using “layer by layer” approach, appropriate probes selected from bio-affinity pairs were immobilized on formed monolayers. For this purpose, these steps were Figure 1 – 2B- Ellipsometric image of the micro-
performed, briefly: (a) combination of surface plasmon patterned substrat resonance technique and total internal reflection Protein-protein interactions based on protein A-IgG ellipsometry; (b) application of different metal films interactiones is modeled for the second micropattern yielding surface plasmon resonance phenomena on Detection limits for IgG was determined to be 80 nM. same chip surface; (c) micro-patterning of surface Both sequences in 100 minutes on the same chip and plasmon resonance enchanted (SPRe) total internal ODN target protein produced a signal that reaches reflection ellipsometry (TIRE) sensor chip; (d) equilibrium.In addition, the sensor only when used for application of appropriate modification on micro- on-off signal of the chip (on a signal to noise ratio) and patterned chip surface by layer by layer approach; and ODN as well as the time appointed for the target protein (e) evaluation of performance of produced sensor chip. is around 30 minutes.for InfA This project consists of 4 work packages (IPs). In the IP1, substrate preparation for sensor chip and micro- patterning of this chip surface by photolithography technique were performed. In the IP2, micro-patterned chip substrate was functionalized by using protective and multi-step modification method. Oligonucleotide probe which has specific sequence for Avian Influenza (H1, N1) and Protein A probe were immobilized on to functionalized micro-patterns to get a specific pattern (IP3). Finally, performance of designed sensor chip on SPRe-TIRE configuration was evaluated. At this step, sensor signal was acquired against reaction duration, Figure 2 – IgG- interaction of Protein A sensor while complementary ODN (target) and H-IgG (target) response. molecules are interacted with the sensor chip under 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0211
Evaluation of Methods for the Detection of Oxygen in Packaged Food Products
Meryem Yılmaz1*, Elif Atay1 and Aylin Altan1
1Department of Food Engineering, Mersin University, Mersin, Turkey
*Presenter: [email protected]
Abstract been promising for oxygen detection in modified Detection of oxygen is very important to packaged food atmosphere packaging applications [6]. products. Food has respiration capability and the gas There are many established methods for the detection of composition in the package can change as a result of oxygen, involving colorimetric, fluorescent and interaction of food with its environment [1]. Therefore, conductivity methods, however, such instruments are oxygen in the gas composition can be one of the main costly, required trained users to operate, lack of cause of food spoilage, resulting in aerobic microbial portability and time consuming to allow full quality growth, oxidation of food components such as lipids assurance. Therefore, there is an increasing interest in and micronutrients, and changes in color, flavor, bad cheap and simple developments today for using oxygen smell, etc [2]. Therefore, intensive studies have been indicators [6-7]. made to develop oxygen sensors and oxygen indicators In recent years electrospinning method is an open for which can simply detect oxygen gas. In contrast to improvement and popular technology because it offers oxygen sensors which are able to detecting oxygen advantages such as control over morphology, porosity molecules and transforming the detecting information and composition by using simple equipment. into electrical signals in a quantitative manner, oxygen Nowadays, this method can be used for production of indicators are described as devices that enable people to biosensors to detect of oxygen in packaged products. recognize changes in the optical absorbance of organic dyes or pigments according to the oxygen concentration References in the form of changes in color in a semi-quantitative or [1] De Jong, A.R., Boumans, H., Slaghek, T., Van a rather qualitative manner. Therefore, oxygen Veen, J., Rijk, R., Van Zandvoort, M. 2005. “Active and indicators can offer many advantages over oxygen intelligent packaging for food: Is it the future?” Food sensors due to their impregnability from electrical and Additives & Contaminants, 22: 975-979. electromagnetic interferences, strength, tiny size and [2] Vermeiren, L., Devlieghere, F., Van Beest, M., De their low expense [3]. One of the established method for Kruijf, N., Debevere, J. 1999. “Developments in the the detection of oxygen, fluorescent-based oxygen sensors have been used to remote measurement of active packaging of foods”, Trends in Food Science headspace gases inside packaged products. Sensors Technology, 10:77-86. [3] Sumitani, M., Takagi, S., Tanamura, Y., Inoue, H. designed in this study normally have been taken place a 2004. “Oxygen Indicator Composed of an fluorescent or phosphorescent dye encapsulated in a Organic/Inorganic Hybrid Compound of Methylene solid polymer matrix and added to a suitable support Blue, Reductant, Surfactant and Saponite”, Analytical material. If there are molecular oxygen in the packaged Science, 20: 1153-1157. products, it quenches the luminescent dye and can be [4] Hogan, S.A., Kerry, J.P. 2008. “Fluorescent Based quantified against predetermined calibrations. The Oxygen Sensors”, In Smart Packaging Technologies for process is reversible and there are not side products [4]. Fast Moving Consumer Goods. Another method used for the detection of oxygen is [5] Iwamori, S., Nishiyama N., Oya, K. 2015. “A colorimetric method. With colorimetric method, colorimetric indicator for detection of hydroxyl radicals methylene blue based on the nafion film has been prepared and chemical reactions in contact with active in atmosphere using a methylene blue dye based on oxygen species have been estimated. Methylene blue nafion film”, Polymer Degradation and Stability, 123:131-136. used for colorimetric oxygen indicator has been [6] Suramya, D. F. Mihindukulasuriya, Loong-Tak, L. preferred for that one of redox dyes. Therefore, in this 2013. “Oxygen detection using UV-activated study, decolorization mechanism of the film due to electrospun poly (ethylene oxide) fibers encapsulated exposure of the active oxygen species has been with TiO2 nanoparticles” Journal of Materials Science, discussed [5]. 48: 5489-5498. Other method used for the detection of oxygen, UV- [7] Wolfbeis, O. S. 1991.“Fibre Optic Chemical Sensors activated oxygen indicator has been developed by using and Biosensors”, CRC Press. electrospinning in this study. By dispersing TiO2 nanoparticles, glycerol and methylene blue in poly ethylene oxide solution using aqueous ethanol as a solvent, the oxygen indicator has been prepared. As a result, this study showed that TiO2-based indicator has 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0213
Sensitive detection of Melanoma-associated antigen by regenerative immunosensor based on ITO modified with self-assembled silane monolayers
Aslı Gündoğdu1, Münteha Nur Sonuç Karaboğa2,3* and Mustafa Kemal Sezgintürk1
1 Department of Chemistry, Namik Kemal University, Tekirdag, Turkey 2 Department of Chemistry , Institute of Science, Namik Kemal University, Tekirdag, Turkey 3 School of Health, Namik Kemal University, Tekirdag, Turkey
*Presenter: [email protected]
1. Introduction In the end, the presented biosensor was performed to real serum and compared with standart literature Melanoma-associated antigens (MAGE), a group of findings. Morphological characteristics of constructed well-characterized members of the Cancer/testis biosensor were observed by scanning electron antigens (CTA) family. The MAGE family has been microscopy (SEM). divided into two big categories: MAGE-I and MAGE-II based on their tissue-specific gene expression and Consequently, the present biosensor system has chromosomal location. [1-2] Most of them are highly significant advantages and these biosensor give hope in expressed in various forms of cancer, normally terms of applicability in clinical diagnosis of some expressed in testis, trophoblast, and placenta. [3] Since cancer types. MAGE antigens are strictly tumor-specific, they have the potential to become the ideal targets for cancer Acknowledgement: Support from TÜBİTAK (The immunotherapy. [4] To date, the protein expression of Scientific and Technological Research Council of the MAGE family and their correlation with clinico- Turkey, Project number: 113 Z 678) is greatly pathological characteristics has been carried out in acknowledged. various solid tumors including hepatocellular carcinoma, lung cancer , renal cell carcinoma, epithelial References ovarian cancer , gastric and colorectal cancers , and lymphoma. In addition, a larger cohort exploration [1] Xu X, Tang X, Lu M, Tang Q et al., Exp Mol concerning MAGE expression was also performed in Pathol. 2014, 97(3):579-84 head and neck squamous cell carcinoma (HNSCC). [5] [2] Sang M1, Wang L, Ding C, Zhou X, Wang B, Cancer Lett. 2011 Mar 28;302(2):85-90 From this view, present study aimed to a novel, disposable and, cost-effective immunosensor based on [3] Achim A. Jungbluth, Wilson A. Silva, Jr., Kristin indium tin oxide (ITO) sheets modified with silane Iversen, Denise Frosina Cancer Immun. 2007; 7: chemistry to selectively analyze MAGE-1, a potentional 15. biomarker. [4] Nathalie Vigneron, Biomed Res Int. 2015; 2015: 2. Results and Discussion 948501
In present study, the novel and simple biosensor system [5] Achim A. Jungbluth, Klaus J. Busam , Denise was developed to detect MAGE. Carboxyethyl silane Kolb International Journal of Cancer Volume etriol was used firstly as a self assembled monolayer 85, Issue 4, pages 460–465 agent. The activation of -COOH groups was carried out using 1-ethyl-3-(3-dimethylaminopropyl) carbodimide (EDC) /N-hydroxysuccinimide (NHS) couple. Analytical characteristics of constructed biosensor such as square wave voltammetry, linear determination range, repeatibility, reproducibility and regeneration of biosensors are determined. All characteriation steps are monitored by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The presented biosensor has wide determination range (0.004 pg/mL- 0.2 pg/mL). To investigate long shelf life of the fabricated biosensor, the immunosensors were stored at 4°C for periods ten weeks. Beside, binding kinetics of MAGE to anti-MAGE is monitored by single frequency technique in real time. Moreover, Kramers Kronig transformations were performed for validation of obtained EIS data in all steps of biosensor fabrication. 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0252
Hydrodynamic Trapping of Micro-Liter Droplets and Biological Samples
Adil Mustafa1, Nima Bavili*1, Melikhan Tanyeri2, Ahmet Erten3 , Alper Kiraz1
1 Department of Physics, Koç University, İstanbul, Turkey 2 Department of Electrical Engineering, Özyeğin University, İstanbul, Turkey 3 Department of Electrical Engineering, Osmaniye University, Osmaniye, Turkey
*Presenter: [email protected]
1. Introduction References
Hydrodynamic trapping has been introduced recently as [1] A. Mustafa, A. Erten, R. M. A. Ayaz, O. a powerful tool for trapping and manipulation of micro Kayıllıoğlu, A. Eser, M. Eryürek, M. Irfan, M. beads, DNA molecules, cells or generally any Muradoglu, M. Tanyeri, and A. Kiraz, Enhanced micron/nano sized particles. The technique finds its Dissolution of Liquid Microdroplets in the Extensional novelty in its non-contact based trapping. Creeping Flow of a Hydrodynamic Trap. Langmuir, 2016, 32 (37), pp 9460–9467 2. Experiments [2] Duncan, P. B.; Needham, D. Microdroplet One of the major and most recent applications of this dissolution into a second-phase solvent using a method is investigating the dissolution of liquid micro micropipet technique: test of the Epstein-Plesset model droplets in aqueous solutions [1]. One parameter for an aniline-water system. Langmuir 2006, 22, characterizing the dissolution is diffusion coefficient or 4190−4197. in other terms, mass transfer coefficient. Diffusion coefficient is an important parameter for industrial [3] Harland, R. S.; Gazzaniga, A.; Sangalli, M. E.; applications such as separation/sorting processes and Colombo, P.; Peppas, N. A. Drug/polymer matrix drug delivery/design [2-4]. Work is under progress on swelling and dissolution. Pharm. Res. 1988, 5, 488−494. implementing hydrodynamic trapping method for biological samples such as RBC. Experiments are also [4] O’Donnell, P. B.; McGinity, J. W. Preparation of being performed on measuring deformation of microspheres by the solvent evaporation technique. hydrodynamically trapped low surface tension micro Adv. Drug Delivery Rev. 1997, 28, 25−42. [5] Epstein, droplets, which is also applicable to biological samples. P.; Plesset, M. On the Stability of Gas Bubbles in Liquid-Gas Solutions. J. Chem. Phys. 1950, 18, 3. Results 1505−1509.
We have observed the dissolution using micro droplets of benzyl benzoate and n-decanol trapped in water and surfactant (DSS) solution at different flow rates. The results show that rate of dissolution of micro droplets increases at high flow rates. The rate of dissolution also changes from benzyl benzoate to n-decanol with ndecanol dissolving faster than benzyl benzoate. The results also showed that dissolution also is affected by amount of surfactant in the solution. Obtained data from experiments were analyzed and used to modify the Epstein-Plesset equation [5].
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0214
Determination of protein activated kinases 2 (PAK 2) by a sensitive electrochemical biosensor
Nergiz Kılınç1* and Mustafa Kemal Sezgintürk1
1 Namik Kemal University, Faculty of Arts and Science, Chemistry Department, Biochemistry Division, Tekirdag, Turkey
*Presenter: [email protected]
1. Introduction electrodes. Analytical characteristics such as square wave voltammetry, linear determination range, Among the many different signaling molecules that repeatibility, reproducibilty and regeneration of regulate cell survival and cell death are the p21 biosensors were determined. All characterization steps activated protein kinases (PAKs). PAKs are activated in were monitored by Cyclic voltammetry (CV), and re electrochemical impedance spectroscopy (EIS) sponse to extracellular signals and regulate cell shape techniques. To achieve reproducible and repeatable and motility as well as cell survival and programmed biosensor system, all parameters such as SAMs cell death. The mammalian PAK family consists of six concentration, antibody concentration and antibody members that can be divided into two subfamilies incubation time were optimized. The presented according to sequence homology. The first subfamily biosensor has wide determination range (5 fg-75 consists of PAK-1 (alpha-PAK), PAK-2 (gama-PAK), fg/mL). and PAK-3 (beta-PAK). PAK-1 and PAK-3 are tissue- Acknowledgement: We are thankful for financial specific with the highest levels in brain, whereas PAK-2 support from the Scientific and Technological Research is ubiquitous. The second subfamily consists of the Council of Turkey (TÜBİTAK, Project number: 113 Z more recently identified PAK-4, PAK-5, and PAK-6. 678). p21-activated protein kinases (PAKs) are a family of serine/threonine protein kinases that are activated by References binding of the p21 G proteins Cdc42 or Rac. The ubiquitous PAK-2 (gama-PAK) is unique among the [1] Rolf Jakobi, Corine C. McCarthy, Mark A. Koeppel, PAK isoforms because it is also activated through and Daniel K. Stringer.’’ Caspase-activated PAK-2 Is proteolytic cleavage by caspases or caspase-like Regulated by Subcellular Targeting and Proteasomal proteases. In response to stress stimulants such as tumor Degradation*.Vol. 278, No. 40, Issue of October 3, pp. necrosis factor alfa or growth factor withdrawal, PAK-2 38675–38685, 2003 Printed in U.S.A. is activated as a full length enzyme [1]. Silica gel is an amorphous inorganic polymer composed of siloxane [2] Seung Won Park, Jeewon Lee, Suk In Hong, Seung groups (Si-O-Si) in the inward region and silanol groups Wook Kim.’’ Enhancement of stability of GL-7-ACA acylase immobilized on silica gel modified by epoxide (Si-OH) distributed on the surface. Modification of silica gel by inorganic or organic functional groups has silanization. Process Biochemistry 39 (2003) 359/366 been the subject of considerable interest due to many possibilities of application. Surface modifications are usually achieved with silanization using an appropriate organosilane agent. One of the most widely applied organo-functional alkoxysilanes is 3- glycidoxypropyltrimethoxysilane (3- GPTMS). Its epoxide groups are convenient for the covalent binding of enzyme and proteins. The O-C and N-C bonds formed by the epoxide groups are extremely stable, so that the epoxide-containing polymers can be used for the immobilization of enzyme and proteins [2]. 2. Result and Discussion In this study, we designed a novel biosensor to detect PAK-2 biomarker constructed on modified indium tin oxide (ITO) disposable electrodes. Anti-PAK2 was immobilized through covalent with 3- glycidoxypropyltrimethoxysilane which formed a self- assembled monolayers (SAMs) on modified ITO 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0215
Preparation of Poly(thionine) Supported Platium Nanoparticles For Electrocatalytic Applications
N. Çoşkun Kurt1* and M. Sönmez Çelebi1
1Department of Chemistry, Faculty of Science and Arts, Ordu University, 52200, Ordu, Turkey
*Presenter: [email protected]
1. Introduction 3. Results and discussion Fuel cells are regarded as promising energy sources for Thionine was electrochemically polymerized onto the the future to replace the traditional systems which use PGE surface by cyclic voltammetry from aqueous fossil fuels. During the operation of a fuel cell, the solution of TH containing 0.5 M H2SO4 as the chemical energy of the fuel (hydrogen, methanol, supporting electrolyte. Polymerization profile of PTH is ethanol, formic acid, etc.) and the oxidant (oxygen gas given in Figure 1. or hydrogen peroxide) is catalytically converted to electricity at the active interface regions between the electrodes and the electrolyte. Fuel is oxidized in the anode whereas reduction of the oxidant takes place in the cathode [1,2] The catalyst layer on the electrodes contains precious (often Pt) or non-precious metal particles which are generally supported on a suitable material. Pt-based catalysts are used frequently for construction of both anodes and cathodes while non- precious metals are generally used in the cathode compartment. Therefore, electrode materials are of great Figure 1 Polymerization profile of TH importance for increasing the efficiency and reducing the cost of a fuel cell system. Metal nanoparticles have Pt particles were incorporated into the polymer matrix interesting and unique properties compared to larger via cyclic voltammetric scans in 2 mM K2PtCl4 solution corresponding metal particles. Metal particles with nano without supporting electrolyte. The Pt complexes and uniform sizes have many applications in optics, immobilized in the redox polymer matrix were then electronics, magnetic devices and as catalysts, reduced by chemical reduction using hydrazine as the photocatalysts, adsorbents and sensors. Generally, the reducing agent. small particle size and high dispersion of metal particles The PTH supported Pt nanoparticles prepared as will result in high electrocatalytic activity [3]. Metal described above showed excellent catalytic activity nanoparticles supported on functional polymers have towards electrooxidation of methanol (Figure 2). It can many advantages such as generation of metal be stated that PTH supported Pt nanoparticles can be nanoparticles with a controlled size and size distribution used as anode catalysts for direct methanol fuel cells. and influencing the chemical behavior of metal nanoparticles via interaction with the polymer bound functional groups [4]. In the current work, synthesis of poly(thionine) (PTH)-supported Pt particles on pencil graphite electrode was described. Pt particles were incorporated into the polymer matrix via cyclic voltammetric scans in aqueous K2PtCl4 solution without supporting electrolyte. The Pt complexes immobilized in the redox polymer matrix were then reduced by chemical reduction using hydrazine as the reducing agent. The Pt nanoparticles were tested for Figure 2 CV of 0.5 M methanol + 0.5 M H SO electrocatalytic oxidation of methanol for fuel cell 2 4 applications. References 2. Experimental [1] J. Yuan, B. Sunden, Int J Heat Mass Tran, 69, 358 (2014) In electrochemical studies, a pencil graphite electrode [2] Y, Wang, K.S. Chen, J. Mishler, S.C. Cho, X.C. Adroher Appl Energ, 88, (PGE) (r = 0.25 mm) was used as the working electrode. 981 (2011) A saturated calomel electrode (SCE) was used as the [3] M. Adlim, M.A. Bakar, K.Y. Liew, J. Ismail, J. Molecular Catalysis: A reference electrode and a Pt wire was used as the Chemical, 212, 141 (2004). counter electrode. Cyclic voltammetry studies were [4] M. Kralik and A. Biffis, J. Molecular Catalysis: A Chemical, 177, 113 carried out with CH Instruments System, Model 600E. (2001). 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0216
Molecularly Imprinted Electrochemical Sensor for Selective Determination of Proline
Nihal Ermiş1*, Melike Baskaya and Nihat Tinkiliç1
1 Department of Chemistry, Ondokuz Mayıs University, Samsun, Turkey
*Presenter: [email protected]. tr
1. Introduction solutions of this similar molecules The prepared imprinted sensor was applied for the Proline is a very important amino acid because of its detection of piroline levels in honey samples with vital role in protein synthesis and structure. Besides it standart addition method. Honey was obtained from a takes part in wound healing, antioxidative reactions [1]. local market. As a comparative study, piroline content in In general, molecular imprinting method is used via honey was analysed through Ough method also. The polymerization of proper monomers around a selected results were satisfactory. template. By using an elution agent, template molecules leave complementary cavities to its three dimensional 3. Results and Discussion structure. On interaction with the imprinted polymer and template molecule containing solution, via these Electrochemical characterization of MIP electrode was cavities polymer behaves as a recognition element. [2] made via CV technique as seen on Figure 1. Same Through mixing this method and electrochemical technique was also used to show up the difference techniques, analyte selectivity and specifity can be between NIP and MIP modified electrodes. According gained. In this study, the fabrication of a highly to the results of selectivity analysis, the adsorption selective and sensitive proline sensor was investigated capacity of NIP modified electrode was almost the same using a polypyrrole (PPy) polymer as an artificial for each molecule while MIP electrode showed higher recognition element. Pyrrole and piroline were used as selectivity to proline instead of other selected the functional monomer and template molecule, molecules. respectively. Electropolymerization on gold electrode was used to prepare a novel sensor for detecting piroline
without any extra reagent like enzyme or mediator.
2. Experimental All electrochemical experiments and electropolymerization were performed on a VersaStat 3 0 0,2 0,4 0,6 0,8 electrochemical system (Princeton Applied System) (uA) Current connected to a personal computer. The three-electrode system was consisted of Au (1.6 mm in diameter), Volt (V) Ag/AgCl/KCl (saturated) electrode and Pt wire, as working, reference and auxillary electrode, respectively.
The surface of the gold electrode was polished on a Figure 1 Difference between bare and MIP microcloth with 1.0 and 0.05 μm aqueous slurry of modified electrode (blue-bare ;red-MIP alumina. After this it was cleaned in an ultrasonic bath electrode) in water for 5 min to remove any particles on the surface and then allowed to dry at room temperature. Consequently a novel sensor which can detect piroline, The electrosynthesis of PPy film was performed by in a wide range levels and lower detection limit was cyclic voltammetry (CV), between -0.2 and 1.2 V vs. synthesized. According to the results specificity, Ag/AgCl, at a scan rate of 100mV/s. Under same sensitivity, reproducibility were also good and through conditions, without template molecule a non-imprinted MIP method higher selectivity and sensitivitiy gained. polymer (NIP) was synthesized in order to examine difference. For electrochemical characterization of MIP References and NIP modified electrode, CV was used. Electroanalytical measurements were performed with [1] Wu Guoyao. et al. Proline and hydroxyproline metabolism: different concentrations of piroline solutions between 1 implications for animal and human nutrition (Amino Acids. and 25 nM with square wave voltammetry (SWV) 2011 Apr; 40(4): 1053–1063 technique. The selectivity of the imprinted electrode to [2] Vasapollo G. et al. , Molecularly Imprinted Polymers : tyrosine was evaluated by SWV with the other two Present and Future Perspective, International Journal of Molecular Sciences 12 (2011) 5908-5945 similar molecules, leucine and valine . After template removal, MIP modified electrodes were immersed in 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0217
Guanin Signal Enhancement at DNA Biosensor Using Metal Nanoparticules- Mixed Silica Gel: Application to Hybridization Detection on Biosensor Surface
Nilay Aladag Tanik1*, Elif Demirkan1 and Yakup Aykut2
1 Department of Biology, Uludağ University, Bursa, Turkey 2 Department of Textile Engineering, Uludağ University, Bursa, Turkey
*Presenter: [email protected]
1. Introduction In Fig. 1, we compared the guanine signals obtained from probe by using only silica gel, silver, cobalt, zinc In this study, we have detected the hybridization nitrate salts and silica gel with silver, cobalt, zinc nitrate electrochemically on the pencil graphite electrode salts. First of all, 20% silica gel, silver, cobalt, zinc (PGE) surface and we used to cobalt (Co) nanoparticles nitrate solutions and silica gel solution with 20% silver, and silica gel for the signal enhancement. For cobalt, zinc nitrates were prepared in ultrapure water. determining the mutation or polymorphism, RFLP, RT- The highest signal ratio was observed with solution of PCR, and DNA sequencing methods are generally used. silica gel and cobalt nitrate salts and this surface But, these methods are expensive and they also requires modification was used for further experiments. expertise and quite time-consuming sample preparation processes. It was found that to be possible the detection of hybridization with label-free methods which are based on a guanine signal. 2. Experimental Oxidation signal of most electroactive and stable DNA’s base, guanine, approximately at about +1.0V is used in this study. It is the first time that pencil graphite electrode (PGE) surface is coated with silica gel which is containing metal nanoparticles. PGE modification was performed by immersing the PGE in ultrapure water containing different concentration of silica gel with different concentration of silver, zinc and cobalt nitrate salts. After the PGE surfaces coated with silica, PGEs were placed outside to dry. Probe was immobilized onto the modified PGE containing probe. Figure 1. The guanine signals and percentage increase After immobilization, probe-modified PGEs were rinsed guanine signals of probe coated surface under different for the removing of the unbound DNA at the electrode surface modifications. surface. Probe modified PGE were immersed into the target solutions and waited at the room temperature for immobilization. After hybridization, non-specific adsorption effects were minimized with the following washing step. The treated and washed electrode was transferred into ABS (pH 4.80) and the oxidation signal of guanine was measured by using DPV in ABS by scanning +0,75 to +1,25 V. Silica gel and metal ion concentrations, selection of buffer solution for probe, for hybridization and for measurement, probe and target concentrations, probe immobilization time, Figure 2. Voltammograms of guanine signals hybridization time and washing time after the hybridization were studied in order to find optimum 4. Conclusions analytical performance of the developed sensor. 3. Results and Discussion These results showed that the developed biosensor selectively connect to the target and showed that it is For the determining of optimum operation conditions, it possible to determination of hybridization. Our method was based on that the oxidation signal of guanin signal is easy to apply, no need to expensive equipment, fast at the single-strand DNA (ssDNA) is more than the response system, and no using of any toxic or signal at the double-strand DNA (dsDNA). The radioactive agents. For these reasons, it is powerful conditions which give the best possible distinction alternative to classical methods. between the ssDNA, dsDNA were determined as the optimum conditions of assay.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0218
Self-Powering Biosensors for Biofuel Cell Applications
Nilgün Dükar1*, Mehmet Yılmaz2, Gökhan Demirel2 and Filiz Kuralay1
1Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey 2Department of Chemistry, Faculty of Sciences, Gazi University, 06500 Ankara, Turkey
*Presenter: [email protected]
Abstract Biofuel cell (BFC) is a type of fuel cell that uses microorganisms to produce electricity, rather than precious metals. They work on the same general principles as all fuel cells: use a catalyst to separate electrons from a parent molecule and force it to go around an electrolyte barrier to generate an electric current. There are 2 types of biofuel cells: Enzymatic biofuel cells and microbial fuel cells. An enzymatic biofuel cell is a specific type of fuel cell that uses enzymes as a catalyst to oxidize its fuel, while a microbial fuel cell is a bio-electrochemical system that drives a current by using bacteria and mimicking bacterial interactions found in nature. Enzymatic biofuel cells have attracted considerable Figure 1 Schematic representation of the work interest owing to their ability to provide sustainable energy from renewable fuel sources under mild conditions [1-5]. The ability to engineer these devices to References process various renewable biochemical species holds considerable promise for the utilization of BFCs as [1] M. Zhou, N. Zhou, F. Kuralay, J.R. Windmiller, S. implantable power sources for biomedical devices. Parkhomovsky, G. Valdes-Ramirez, E. Ktaz, J. Wang, Angew. Chem. Int. Ed. 51 (2012) 2686. In this study, we describe a self-powered enzyme- based [2] M. Zhou, F. Kuralay, J.R. Windmiller, J. Wang, biosensors for biofuel cell applications (Figure 1). The Chemical Communications 48 (2012) 3815. anode of the study consisted of a glucose oxidase (GOx) [3] E. Katz, A.F. Bückmann, I. Willner, J. Am. Chem. entrapped peptide nanostructures (using diphenylalanine Soc. 123 (2001) 10752. peptides) modified screen printed gold electrode. The [4] Y. Hu, Y. Zhang, C. Xu, L. Lin, R.L. Snyder, Z.L. enzyme immobilized nanostructured anode used glucose Wang, Nano Letters 11 (2011) 2572. as the fuel and Meldola’s Blue as the mediator. The [5] M. Gamella, N. Guz, S. Mailloux, J.M. Pingarron, vertical aligned peptide nanostructures were fabricated E. Katz, Electroanalysis 26 (2014) 2552. in a conventional physical vapor deposition system onto [6] G. Demirel, U. Tamer, Nanotechnology 23 (2012) the electrode.6 Then, GOx immobilization was 225604. performed onto the electrode. Lactate dehyrogenase (LDH) entrapped poly(3,4-ethylenedioxythiophene) coated gold electrode was used as the cathode material of the study. 3,4-ethylenedioxythiophene monomer was electropolymerized in the presence of LDH at a constant potential of +0.8 V vs. Ag/AgCl onto the electrode.
Acknowledgments: F. Kuralay acknowledges Turkish Academy of Sciences (TÜBA) as an associate member and TÜBA-GEBİP programme.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0219
Electrochemical Biosensor for Penicillin G Detection
Nilgün Dükar1* and Filiz Kuralay1
1Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey
*Presenter: [email protected]
Abstract Antibiotics play an important role in biological systems. They are large and natural groups of pharmaceuticals used in animals and humans for the treatment of diseases. However, the use of antibiotics may lead to drug residues and accumulation of antibiotics. The accumulation of antibiotics in food-producing animals has become a concern, because of their potential to cause serious threats to public health. Penicillin G belongs to the β-lactam group of antibiotics. The presence of penicillin residues might be responsible for allergenic reaction in human. Penicillin G residues may also be responsible for the development of resistant strains of bacteria [1-3].
Electrochemical techniques used in biosensing Figure 1. Cyclic voltammograms of (a) 2.5 mg mL-1 technology which are capable of high sensivity, good MWCNTs modified electrode, (b) 2.0 mg mL-1 MWCNTs stability, low-cost instrumentation and probability for- modified electrode, (c) unmodified electrode, (d) 1.0 mg on site monitoring have received tremendous attention. mL-1 MWCNTs modified electrode in 0.1 M KCl Recently, most common materials used in biosensor 3-/4- containing 5 mM Fe(CN) . technology are nanaomaterials such as nanoparticles, 6 carbon nanotubes and graphene. Among these nanomaterials, carbon nanotubes are of great interest. References Carbon nanotubes have captured the interest of [1] P. Thavarungkul, S. Dawan, P. Kanatharana, P. researches world-wide due to their small size with large Asawatreratanaku, Biosensors and Bioelectronics 23 surface area, high electrical conductivity, chemical (2007) 688. stability, and mechanical strength. [4]. [2] Z. Yan, N. Gan, T. Li, Y. Cao, Y. Chen, Biosensors
and Bioelectronics 78 (2016) 51. In this study, we present a multiwalled carbon nanotubes [3] L.M. Gonçalves, W.F.A. Callera, M.D.P.T. (MWCNTs) modified disposable screen printed gold Sotomayor, P.R. Bueno, Electrochemistry electrode for the detection of Penicillin G. In the first Communications 38 (2014) 131. part of the study, MWCNTs, prepared at different [4] F. Kuralay, M. Dumangöz, S. Tunç, Talanta 144 concentrations, were modified on the disposable gold (2015) 1133. electrode surface. The electrochemical behavior of the electrodes were investigated in 0.1 M KCl solution 3-/4- containing 5 mM Fe(CN)6 redox probe (Figure 1). Penicillinase enzyme was then immobilized and amperometric detection of Penicillin G was performed. Cyclic voltammetric behaviors of the modified electrodes were also examined. The biosensor monitored the catalytic hydrolysis of Penicillin G in a very sensible manner.
Acknowledgments: F. Kuralay acknowledges Turkish Academy of Sciences (TÜBA) as an associate member and TÜBA-GEBİP programme.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0220
Gold Nanoparticle-based Colorimetric Assay for Chiral Discrimination of D-/L-Alanine Enantiomers
Nisa Bekar1* and Erhan Zor2
1 Department of Chemistry Education, Necmettin Erbakan University, Konya, Turkey 2 Department of Science Education, Necmettin Erbakan University, Konya, Turkey
*Presenter: [email protected]
4. Introduction red-shifted in the presence of L-alanine whereas no change was monitored in the presence of D-alanine. The development of a simple and efficient method for These results indicate L-alanine could selectively induce enantioselective chiral discrimination is tremendously aggregation of AuNPs, but D-alanine shows no effect. valuable for drug discovery, pharmaceuticals and biochemical processes [1]. In recent years, great success has been attained in chiral discrimination by high- performance liquid chromatography, gas chromatography and electrochemical techniques. Apart from the conventional application of these techniques, one of the most pressing challenges in chiral discrimination is to achieve rapid and simple visual discrimination of enantiomers by naked-eye. Considerable effort has been devoted to the synthesis Figure 1 TEM image of the as-synthesized AuNPs and characterization of chiral selective metal nanoparticles. However, the field of colorimetric chiral The inset in Figure 2 displays the colorimetric assay of discrimination using metal nanoparticles still remains chiral discrimination in which a well-marked red-to- unexplored. In recent decades, the use of gold blue color change was observed in the presence of L- nanoparticles (AuNPs) as optical label leads to a wide alanine, whereas no color change could be observed in range of applications in (bio)sensors due to their the presence of D-alanine. characteristics such as ease of synthesis and their intense red color easy to be detected even by naked eye [2]. Taking advantage of AuNPs, we herein report a colorimetric assay for chiral discrimination of D/L- alanine enantiomers. The mechanism is based on the inherent chirality of citrate-capped gold nanoparticles that can be used as chiral selector for D- and L-alanine.
2. Experimental
AuNPs were synthesized according to Turkevich method [3]. Briefly, a sodium citrate solution (1%, 1.25 mL) was rapidly added to a boiled HAuCl4 solution under vigorous stirring. The mixed solution was boiled for 10 min while observing the color change from deep Figure 2 Absorption spectra of AuNPs in the presence blue to wine-red. The resulting solution was cooled to of D-alanine, L-alanine. The inset shows the room temperature and stored in the refrigerator (4 ˚C). colorimetric assay photographs
3. Results and Discussion Taking advantage of the inherent chirality of AuNPs, it can be concluded that the proposed simple sensor can Figure 1 shows TEM image of the as-synthesized be used as a convenient colorimetric probe to spherical AuNPs with the average size 8 nm. Aiming at discriminate alanine enantiomers, which can be a examining the chiral recognition ability of the AuNPs promising model for discrimination of other biologically D-/L-alanine were added into the AuNPs solution, then important enantiomers of chiral molecules. visual and spectroscopic detection was performed. Figure 2 shows UV-Vis spectra of as-synthesized 4. References AuNPs, D-alanine/AuNPs and L-alanine/AuNPs solutions. An absorption maximum was observed at 518 [1] Wattanakit et al., Nature Commun., 2014, 3325, 1-8. [2] Quesada-González and Merkoçi, Biosens. Bioelectron., 2015, 73, nm originating from the surface plasmon absorption of 47-63. the dispersed AuNPs. The absorption maximum was [3] Turkevich et al., Discuss. Faraday. Soc. 1951, 11, 55–75.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0222
Double-Arm Schiff Bases-Tagged Nanomaterial; Synthesis and Acetylcholinesterase Immobilization
N. Kurnaz Yetim1,2*, E. Hasanoğlu Özkan1, E. Karmaz1 and N. Sari1
1 Department of Chemistry, Gazi University, Ankara, Turkey 1 Department of Chemistry, Kırklareli University, Kırklareli, Turkey
*Presenter: [email protected]
Introduction
Recently there has been a considerable interest in the material chemistry of nanoparticules involving metal ion because of their potential medicine and industrial applications [1]. The use of nanoparticules in medicine and more specifically drug delivery is set to spread rapidly. Nanoparticules involving metal ion play a very important role not only in chemical reactions (enzymatic reactions) in the human body but also in industrial chemical processes [2]. AChE biosensors have been used to detect unknown toxic mixtures, but there are some problems with the identification of toxic mixtures in samples. Therefore, new methods are being investigated by authors. One of these methods is the immobilization of enzymes onto nanospheres. There has been an increase in studies on enzyme immobilization on nanospheres due to their small size and large surface area.4,5 Nanospheres are useful for improving the Figure 1 Mechanism for the catalytic activity of AChE operational stability of immobilization. Therefore enzyme immobilization into or onto various Kinetic parameters were studied for free AChE and nanoparticles has been proposed and reported. immobilized AChE optimum at pH=8.0 and optimum temperature (50 oC). Km/Vmax values were calculated Experimental from Lineweaver-Burk plots for immobilized AChE to the novel support, 1.443 mM and 0.251 mMmin-1 To prepared such a support, the N-{2-[Bis(2- respectively for 50 °C. patterns because they may not be aminoethyl)amino]ethyl}aminomethyl-polystyrene reproduced properly. (2AEPS) reacted with 2-bromo salicylaldehyde by means of condensation method. Table 1Kinetic parameters (Km/Vmax; mM/mM min−1) for free AChE and immobilized AChE 4.1. Immobilization of AChE on nanomaterial pH Temp. Km/Vmax (2AEPS-SalBr) (°C) (mM/ mM min−1) After dissolving enzyme in pure water (50 mL, 3.6 x 10- Free Enzyme 8 50 0.146/1.85 4 gL-1), 2AEPS-SalBr polymer (0.5 g) was placed to a 2 mL of 3.6 x 10-4 gL-1 of AChE. This solution was AChE-2AEPS- 8 50 1.443/0.251 diluted to 10 ml and at room temperature in a shaking SalBr water bath for 8 h. The immobilized polymer was separated and the free enzyme was removed by washing with phosphate buffer and then stored at + 4 °C. References [1] M.C.Daniel, D. Astruc, J. Chem. Rev. 104 (2004) 293. Conclusion The apparent kinetic parameters of the immobilized [2] W.H. De Jong, P.J.A. Borm, Int. J. Nanomed. 3 (2) (2008) 133. enzyme and free enzyme were compared, and this [3] E. Hasanoğlu Özkan, N. Kurnaz Yetim, D. Nartop and N. Sarı, J. showed that the Michaelis constant (Km) of the Indian Eng. Chem., 25 (2015), 180. immobilized AChE was higher than that of the free AChE, while there was a significant difference in the [4] N. Özdem, E. Hasanoğlu Özkan, N. Sarı, F. Arslan and H. Tümtürk, Macromol. Res. 22(12) (2014) 1282. maximum reaction rates (Vmax).
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0204
A Sensitive Electrochemical Biosensor for Determination of Gallic Acid Based on Polyimide Modified Electrode
Aziz Paşahan1, Nurcan Ayhan1*, İmren Özcan, Serap Titretir Duran1, Süleyman Köytepe1
İnönü University, Faculty of Arts and Science, Chemistry Department, 44280, Malatya, Turkey
*Presenter: nurcan1658hotmail.com Abstract
Gallic acid (GA), a type of phenolic acid, is occurring in plants in the form of free acids, esters, and catechin derivatives[1]. It is commonly used in the pharmaceutical industry and food industry[2]. Gallic acid is used as a standard for determining the phenol content of various analytes. In recent years, many methods such as chemiluminescence spectrophotometry and capillary electrophoresis as well as chromatography were introduced to determinate of phenolic compounds[3-4]. Electrochemical methods were used for determination of GA due to low detection limit, very fast response time, high sensitivity and simplicity[5].
In the present study, a novel polyimide film as selective membranes was synthesized from 1,5- Fig 1. DPV behaviours of 2 mM gallik acid, 2 mM diaminonaphthalene and 3,3',4,4'-benzophenonetetra- caffeic acid, 2 mM Ascorbic acid and 2 mM coumaric carboxylic dianhydride through polycondenzation acid at polyimide modified electrode. reaction and thermal imidization. The prepared polyimide films were characterized for their structure, References morphology, and thermal behavior by Fourier transform infrared spectroscopy (FTIR), scanning electron [1] M. Naczk, F. Shahidi, J. Pharm. Biomed. Anal. 41 micrograph (SEM), X-ray diffraction (XRD) and (2006) 1523–1542 thermal analysis (DTA/TGA/DSC) techniques. The polyimide membrane was exhibited the highest Tg [2] S. M. Fiuza, C.Gomes, L.J. Teixeira, MT. Girao da because of the rigid heterocyclic unit. The polyimide Cruz, M. N. D. S. Cordeiro, N Milhazes, F.Borges, were formed by casting the film on the surface of bare M.P.M. Marques, Bioorganic & Medicinal platinum electrodes in one-step procedure. For the Chemistry 12 (2004) 3581–3589. preparation of PI electrode, firstly, a solution of polymer was made by dissolving about 0,1 g of the obtained dark [3] X. Shao, L.S Lv, T. Parks, H. Wu, C.T. Ho, S.M. amber powdery polyimides in 1 ml of NMP. Then, the Sang, J. Agric. Food Chem. 58 (2010) 12608– prepared polyimide solution (2 µL) was cast on the 12614. surface of bare platinum working electrodes and polyimide film was dried at room temperature for at [4] R.L.C Chen, C.H. Lin, C.Y. Chung, T.J. Cheng, J. least 2 days. Agric. Food Chem 53 (2005) 8443–8446. Differential Pulse Voltammetry (DPV) technique was used to investigate the electrochemical behavior of the [5] B.B. Petkovic, D. Stankovic M. Milcic, S.P. Sovilj, GA and interference species at modified electrode. D. Manojlovic 132 (2015) 513–519 Therefore, it is claimed that the polyimide film can be used as selective matrix for the rapid and accurate detection of gallic acid in the presence of various interferant molecules.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0226
Electrochemical and nonenzymatic glucose biosensor based on MDPA/MWNT/PGE nanocomposite
Özge Sürücü1*, Gulcin Bolat1 and Serdar Abaci1
1 Department of Chemistry, Hacettepe University, 06800, Beytepe, Ankara, Turkey
*Presenter: [email protected]
1. Introduction 2. Results and discussion
Multi-walled carbon nanotubes (MWNTs) are multiple Electrocatalytic performance of the modified surfaces layers of graphite superimposed and form a tubular towards the oxidation of glucose was investigated by shape rolling in on themselves. Organic dyes, especially SWV between -0.8 V and 0.0 V vs. Ag/AgCl in 0.1 M azo dyes can combine with MWNTs with strong π-π NaOH solution containing 5.0 mM glucose. SWVs of interactions to form stable hybrids [1]. Electrocatalytic 1.0 mg mL-1 MWNT and 1.0 mM MDPA co-deposited activity of MWNTs and azo dyes combinations exhibit PGE, 1.0 mM MDPA over 1.0 mg mL-1 MWNT excellent properties such as high mechanical stability deposited PGE, 1.0 mg mL-1 MWNT over 1.0 mM and sensitivity for different electrochemical techniques MDPA deposited PGE and bare PGE were represented possessing excellent responses to various substances in Figure 1. Oxidation process of glucose started at -0.8 such as as redox proteins, drugs, small biomolecules, V following two oxidation peaks at -0.6 V and -0.4 V hormones, and so on. vs. Ag/AgCl. The results indicated that the modification improved the electrocatalytic activity towards the A number of studies have been carried out to monitor oxidation of glucose. The former peak was oxidation of blood glucose levels [2]. Among these studies, glucose to glucolactone and the other was originated electrochemical and optical methods have been from consequent oxidation of glucolactone [3]. The extensively developed to monitor glucose. The main differentation of MDPA over MWNT deposited electrochemical and nonenzymatic sensing of glucose is PGE (red line) was obtained at -0.6 V vs. Ag/AgCl a cost-effective and rapid approach. Recently, various observing 5-folds higher current enhancements from nanomaterials have been developed as excellent bare PGE (green line) and the proposed surface was nanocatalysts to provide new surfaces for fabricating titled as MDPA/MWNT/PGE. novel nonenzymatic glucose sensors.
The nonenzymatic sensing of glucose has been widely investigated in a variety of fields ranging from biomedical applications to ecological approaches. Among these fields, electrochemical methods contain great advantages such as high electrocatalytic ability, high sensitivity and good selectivity to the electrooxidation of glucose. In this study, the strong noncovalent adsorption of novel synthesized (E)-4-((5- methylthiazole-2-yl)diazenyl)-N-phenylaniline (MDPA) on the surface of MWNT/PGE was performed Figure 1. Square wave voltammograms of 1.0 mg mL-1 electrochemically, and the prepared stable, uniform and MWNT and 1.0 mM MDPA co-deposited PGE, 1.0 mM sensitive film (MDPA/MWNT/PGE) was used for MDPA over 1.0 mg mL-1 MWNT deposited PGE, 1.0 nonenzymatic and direct determination of glucose. The mg mL-1 MWNT over 1.0 mM MDPA deposited PGE surface of modified electrodes was characterized using and bare PGE between -0.8 V and 0.0 V vs. Ag/AgCl in scanning electron microscopy (SEM) and 0.1 M NaOH solution containing 5.0 mM glucose. electrochemical impedance spectroscopy (EIS) techniques. The improvement of electrooxidation References response of glucose was completed using MDPA/ MWNT/PGE nanocomposite. The effects of scan rate [1] C. Hu, S. Hu, Journal of Sensors, Volume 2009, and pH on the peak potential and peak current of Article ID 187615, 40 pages. glucose signal were determined. The limit of detection and linear range were calculated using various [2] A. Caduff, M. S. Talary, P. Zakharov, Diabetes concentrations of glucose. Interference studies were Technol. Ther., 2010, 12, 1–9. performed using coexisting substances including metal [3] L. Larew, D. Johnson, J. Electroanal. Chem., 1989, ions such as Al3+, Cu2+, Fe3+ and ascorbic acid to 262, 167–182. determine the selectivity of MDPA/MWNT/PGE for glucose.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0228
pH/Redox-Sensitive Hybrid Nanocarriers for Triggered Delivery
R. Tekiner1,2* and G. Birlik Demirel1,2
1Department of Chemistry, Polatli Faculty of Arts and Sciences, Gazi University, Ankara, Turkey 2 Life Sciences Research and Application Center, Gazi University, Ankara, Turkey
*Presenter: [email protected]
Abstract of the silica shell without premature release until crosslinked polymer shell gatekeepers are cleaved by Cancer remains one of the world’s most devastating glutathione (GSH). In addition to PEG-FA polymers diseases, with more than 10 million new cases provide to enhance the targeted cellular uptake of the every year[1]. In traditional treatment methods, anti- particles by cancer cells. The experimental results cancer drug molecules circulate freely in the blood and showed that smart nanoparticles exhibit fast dissociation do not exhibit targeted release and kill the healthy cells in the presence of 10 mM GSH, due to the reductive besides cancer cells. Because of these reasons and cleavage of intermediate disulfide bonds of PLH-PEG considering the emerging technology, the scientists polymer. It can be said that this multifunctional polymer from many disciplines study intensively for the shell is active for the controlling drug molecules in-and- development of new-generation nanocarrier systems out of silica channels. Moreover, the ellipsoidal smart [2,3]. Nanocarriers have many advantages compared to nanoparticles allowed the perfect release profile under traditional methods. First of all, the drug molecules are cellular pH environment. As a result, this study which trapped into the nanocarriers and the toxicity of drug involve the experimental and applied research, will help can be decreased in minimum levels. Thus uncontrolled the development of new generation nanocarrier systems. delivery can be prevent and the drug dose can be In our belief, the obtained each result from every step adjusted to minimum but effective levels. In the light of will be very precious to reach excellent systems in this the existing information scientists have focused on the field and will provide very big contribute to the multifunctional and routable nanocarrier systems which literature. can do selective and controlled release [4-6]. In this study, we have developed a novel pH/redox-sensitive Acknowledgement: This work was supported by the hybrid nanocarrier system for controlled drug delivery TUBITAK Grant No. 115R280. as seen in Scheme 1. References
[1] Stewart, B. W., Kleihues, P. 2003. “World cancer report world health organization press”, Genova, 9-11.
[2] Drbohlavova, J., Chomoucka, J., Adam V., Ryvolova, M., Eckschlager, T., Hubalek, J., Kizek, R. 2013. “Nanocarriers for anticancer drugs - new trends in nanomedicine”, Current Drug Metabolism, 14, 547-564.
[3] Duncan, R. 2006. “Polymer conjugates as anticancer nanomedicines”, Nat. Rev. Cancer, 6, 688–701
[4] Cho, K. J., Wang, X., Nie, S. M., Chen, Z., Shin, D. M. 2008. “Therapeutic nanoparticles for drug delivery in cancer”, Clin. Cancer Res., 14, 1310-1316.
[5] Mishra, B., Patel, B. B., Tiwari, S. 2010. “Colloidal nanocarriers: a review on formulation technology, types Scheme 1. Schematic mechanism of the intracellular and applications toward targeted drug delivery”, pH/redox-controlled release of designed hybrid system Nanomed.-Nanotechnol. Biol. Med., 6, 9-24. Multifunctional and ellipsoidal hybrid nanoparticles [6] Peer, D., Karp, J. M., Hong, S., FaroKhzad, O. C., (Fe3O4@SiO2@PLH-PEG/PEG-FA) composed of an Margalit, R., Langer, R. 2007. “Nanocarriers as an ellipsoidal Fe3O4 core, a mesoporous silica shell and pH/redox-responsive poly(histidine)-co-poly(ethylene emerging platform for cancer therapy”, Nat. Nanotechnol., 2, 751-760. glycol) (PLH-co-PEG) polymer as gatekeeper and PEG- Folic acid (PEG-FA) polymer as targeted agent to obtain an excellent platform for anticancer drug delivery. In particular, the PLH-co-PEG gatekeeper on the surface of the hybrid nanoparticle play a key role in accommodating anticancer drug molecules in the pore 3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0229
Preparation of a Biosensor for Determination of Choline
R. Baskın1*, E. (Aynacı) Koyuncu1, H. Arslan2 and F. Arslan2
1Department of Chemistry, Institute of Sciences, Gazi University, Ankara, Turkey 2Department of Chemistry, Faculty of Science, Gazi University, Ankara, Turkey
*Presenter: [email protected]
1.Introduction Choline is an amino alcohol and a component of lecitines [1,2]. It has many important biochemical roles. It is one of the fundamental components of cell membranes, a major component of phospholipids (phosphatidylcholine) [3]. Furthermore, choline is the precursor molecule for significant neurotransmitter acetylcholine in both peripheral and central nervous system of mammals [4,5]. So, choline detection and determination is very important for clinical analyses. In this study, we report a new choline oxidase (ChO) and Toluidine Blue O (TBO) based amperometric choline biosensor for the determination of choline.
5. Materials and Methods In this study, an amperometric choline biosensor with immobilization of TBO (as a mediator,), ChO onto polypyrrole-polyvinylsulphonate (PPy-PVS) film was Figure 1 Reaction scheme for the detection of choline accomplished on the surface of a platinum electrode. ChO and TBO were immobilized by a 7. References glutaraldehyde/bovine serum albumin crosslinking [1] Özdemir, M., Arslan, F. and Arslan, H. (2012). An procedure onto PPy-PVS film after the amperometric biosensor for choline determination electropolymerization process. The effects of substrate prepared from choline oxidase immobilized in concentration, pH and temperature on the response of polypyrrole-polyvinylsulfonate film. Artificial Cells, the choline biosensor were investigated. The operational Blood Substitutes, and Biotechnology, 40, 280-284. and storage stability of the biosensor were also studied. [2] Langer, J.J., Filipiak, M., Kęçińska J., Jasnowska, J., Włodarczak, J. and Buładowski, B. (2004). Polyaniline The amperometric response was based on the biosensor for choline determination. Surface Science, electrocatalytic properties of TBO. The changes in the 573, 140-145. anodic current at -0.23 V vs Ag/AgCl produced by TBO [3] Galbán, J., Sánchez-Monreal, O., Andreu, Y., de was proportional to the choline concentration changes in Marcos, S, and Castillo, J.R. (2004). Choline sample (Figure 1). determination based on the intrinsic and the extrinsic (chemically modified) fluorescence of choline oxidase. 6. Results and Discussion Analytical Biochemistry, 334, 207-215. In this study, a novel amperometric choline biosensor [4] Aynacı, E., Yaşar, A. and Arslan, F. (2014). An with ChO, and TBO onto PPy-PVS film was amperometric biosensor for acetylcholine determination accomplished. The optimum working conditions with prepared from acetylcholinesterase-choline oxidase respect to the substrate concentrations were immobilized in polypyrrole-polyvinylsulpfonate film. investigated. The effects of pH and temperature were Sensors and Actuators B: Chemical, 202, 1028-1036. investigated and optimum parameters were found to be [5] Garguilo, M.G. and Micheal, A.C. (1995). 7.0 and 30.0 ˚C, respectively. The storage stability and Optimization of amperometric microsensors for operational stability of the enzyme electrode were also monitoring choline in the extracellular fluid of brain studied and linear range was determined. Interfering tissue, Analytica Chimica Acta, 307, 291-299. effect of some common substances was investigated.
The experimental results clearly showed that the choline biosensor was sensitive and selective and its operational stability and long-term storage stability were found to be good. This biosensor was also easy to prepare and was highly cost effective.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0230
Ascorbic acid, dopamine and uric acid determination using a novel, highly selective and sensitive rGO/PPy-Pt sensor
Fatih Sen1, Sait Bozkurt1* and Ceyda Uluturk1
1Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupinar University, Kütahya, Turkey
*Presenter: [email protected]
Abstract References We report here an efficient and simple approach for the [1] O. Arrigoni and M. C. D. Tullio, Biochim. Biophys. preparation of a partially reduced graphene oxide Acta, 2002, 1569, 1. polypyrrole zinc oxide modified glassy carbon electrode (RGO-Ppy-Pt/GCE). The modification of the RGO- [2] J. H. Kim, J. M. Auerbach, J. A. R. Gomez, I. GCE consists of three steps. These include (i) chemical Velasco, D. Gavin, N. Lumelsky, S. H. Lee, J. Nguyen, synthesis of graphite oxide by a modified Hummer's R. S. Pernaute, K. Bankiewicz and R. McKay, Nature, method,1 (ii) exfoliation of graphite oxide to graphene 2002, 418, 50. oxide (GO) by ultra-sonication and (iii) controlled partial electrochemical reduction in 0.1 M phosphate [3] V. S. E. Dutt and H. A. Mottola, Anal. Chem., 1974, buffered medium (pH 3.0) via potentiodynamic cycling 46, 1777. (2 cycles) to obtain a partially reduced graphene oxide modified glassy carbon electrodes (RGO-GCE). The behaviour of the RGO-GCE towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) was investigated by differential pulse voltammetry, with an enrichment time of 3 minutes.2-3 Morphological (SEM and TEM) and electrochemical characterization studies were also reported. Finally, the performance of the RGO-GCE based sensor was successfully tested for analysing UA and quantitative recoveries of AA and DA in serum samples.
Figure: (a) DPV results of AA, DA and UA at GCE, rGO/PPy-Pt modified electrodes
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0231
Incorporating PPy with ZnO Nanorods on Rgo: A Potentiometric Strategy for Selectivity and Detection of Dopamine, ascorbic and uric acid
Fatih Sen1, Sait Bozkurt1* and Ceyda Uluturk1
1Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupinar University.
*Presenter: [email protected]
Abstract In this study, the investigation regarding the fabrication References of a reduced graphene oxide-polypyrole-platin [1] O. Arrigoni and M. C. D. Tullio, Biochim. Biophys. (rGO/PPy-ZnO) was carried out. The reduced graphene Acta, 2002, 1569, 1. oxide modified glassy carbon electrodes (rGO/PPy- ZnO) were obtained by following procedure; graphite [2] J. H. Kim, J. M. Auerbach, J. A. R. Gomez, I. oxide production, graphene oxide synthesis and finally, Velasco, D. Gavin, N. Lumelsky, S. H. Lee, J. Nguyen, rGO/PPy-ZnO fabrication; chemical synthesis, ultra- R. S. Pernaute, K. Bankiewicz and R. McKay, Nature, sonication and electrochemical reduction via 2002, 418, 50. potentiodynamic cycling were used, respectively. The differential pulse voltammetry (DPV) was utilized to [3] V. S. E. Dutt and H. A. Mottola, Anal. Chem., 1974, check rGO/PPy-ZnO performance against ascorbic acid 46, 1777. (AA), dopamine (DA) and uric acid (UA). At pH 3.0, as-prepared electrode exhibits high sensitivity and give precise and separate data for AA, DA and UA, they can be examined separately and instantly. With 1x10-6 to 1,5x10-5 M detection limit, the series of the amounts of 2x10-1 M AA, 2x10-1 M DA and 1x10-1 to 2x10-1 M UA were determined as the sensing intervals for as-prepared electrode. The as-obtained electrode was characterized by morphologically and electrochemically. At the end, for the analytical determination of UA and for discovering the amount of AA and DA in serum specimen, the rGO/PPy-ZnO was used [1-3].
420,0µ Increase in scan no. 360,0µ UA
300,0µ
240,0µ DA 180,0µ
I/A 120,0µ AA
60,0µ Forward scan 0,0
-60,0µ
-120,0µ -0,2 0,0 0,2 0,4 0,6 0,8
E/V
Figure: (a) CV results of AA, DA and UA (each 1 x 10-3 M, scan rate 50 mV s-1) at GCE, rGO/PPy-ZnO modified electrodes.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0233
Nanomaterials-based DNA Damage Detection
Selma Tunc1* and Filiz Kuralay1
1Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey
*Presenter: [email protected]
Abstract Deoxyribonucleic acid (DNA) is the largest, well- defined and also the most important molecule of life. DNA plays an important role in the life process since it carries heritage information and instructs the biological synthesis of proteins and enzymes through the process of replication and transcription of genetic information in living cells [1-3].
Damage to DNA may result in critical disturbances in the cell life. As a result of the damage, serious impacts on human’s health can occur. DNA damage can lead to diseases such as Alzheimer, Parkinson’s disease and Figure 1 SEM images of (a) unmodified PGE, (b) cancer [4,5]. Thus, there is a considerable interest in the GN/PGE development of highly sensitive and accurate sensing platforms for the detection of DNA damage. Different detection techniques have been employed responding to Acknowledgments: This work has been supported by DNA damage, including fluorescence, surface plasmon L’Oréal-UNESCO For Women in Science Programme. resonance, quartz crystal microbalance and F. Kuralay acknowledges Turkish Academy of Sciences electrochemistry. (TÜBA) as an associate member and TÜBA-GEBİP programme. Electrochemical techniques are well suited for rapid and direct detection of DNA damage since DNA bases are References electroactive. Furthermore, electrochemistry have [1] E. Palecek, Talanta 56 (2002) 809. attracted great attention for the construction of sensitive, [2] F. Kuralay, S. Campuzano, J. Wang, Talanta 99 selective, low-cost, rapid and simple sensing platforms. (2012) 155. Electrochemical biosensors can be operated in turbid [3] F. Kuralay, A. Erdem, S. Abacı, H. Özyörük, A. [1] media, have comparable instrumental sensitivity and are Yıldız, Electrochem. Commun. 11 (6) 1242. more amenable to miniaturization [6,7]. [4] M. Fojta, Electroanalysis 14 (2002) 1449. [5] E. Palecek, M. Fojta, Anal. Chem. 73 (2001) 74A. In this study, we present a graphene modified disposable [6] V. Ostatná, . F Kuralay, L. Trnková, E. Paleček, pencil graphite electrode (GN/PGE) for the detection of Electroanalysis 20 (13) 1406. DNA damage. DNA damage was investigated in the 2+ [7] F. Kuralay, A. Erdem, Analyst 140 (8) 2876. presence and absence of Fenton reagents (Fe /H2O2) [8] M. Zhou, Y. Zhai, S. Dong, Anal. Chem. 81 (2009) according to the changes in the oxidation signals of 5603. DNA bases (Guanine, Adenine, Thymine, Cytosine). In the first part of the study, we synthesized graphene according to the modified Hummers’s method and modified the synthesized graphene onto the graphite electrode surface [8]. Unmodifed PGE and GN/PGE were characterized by scanning electron microscopy (SEM) (Figure 1) and cyclic voltammetry (CV). Then, DNA damage was performed using Fenton reagents. Electrochemical detection of the damage was carried out with differential pulse voltammetry (DPV). Improved electrochemical responses were obtained with the nanomaterials-based electrode compared to the unmodified (bare) electrode. Well-defined oxidation signals of DNA bases were observed using graphene modified disposable graphite electrode, which later on provided a better sensing platform for monitoring the changes in the oxidation signals of DNA bases after the damage.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0234
Electrochemical Investigation of the Effect of Antioxidants on DNA Damage
Selma Tunc1* and Filiz Kuralay1
1Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey
*Presenter: [email protected]
Abstract found that these molecules had the ability to inhibit the Antioxidants are molecules that inhibit the oxidation of DNA damage. other molecules. Chemical reactions-based on oxidation can produce free radicals, leading to chain reactions that may damage cells. It is well-known that antioxidants such as glutathione, catalase, melatonin, uric acid, Vitamin A, Vitamin C (ascorbic acid) (Figure 1) and Vitamin E terminate these chain reactions [1,2].
The reactive oxygen species produced in cells include hydrogen peroxide (H2O2) and free radicals such as the − hydroxyl radical (·OH) and the superoxide anion (O2 ). The hydroxyl radical is particularly unstable and reacts Figure 1 Chemical structure of Vitamin C (ascorbic rapidly and non-specifically with most biological acid) molecules. This species is produced from hydrogen peroxide in metal-catalyzed redox reactions such as the Fenton reaction. These oxidants can damage cells by Acknowledgements: This work has been supported by starting chemical chain reactions such as by oxidizing L’Oréal-UNESCO For Women in Science Programme. DNA [3-5]. This damage to DNA can F. Kuralay acknowledges Turkish Academy of Sciences cause mutations and possibly cancer, if not reversed (TÜBA) as an associate member and TÜBA-GEBİP by DNA repair mechanisms. Researches have been programme. presented that antioxidant molecules can inhibit this DNA damage [6]. References [1] J. Labuda, M. Buckova, L. Heilerova, S. Silhar, I. In the present work, we investigate the effect of ascorbic Stepanek, Anal. Bioanal. Chem. 376 (2003) 168. acid, glutathione and uric acid on the DNA damage 2+ [2] O. Korbut, M. Buckova, J. Labuda, P. Grundler, produced by Fenton reagents (Fe /H2O2). A graphene Sensors 3 (2003) 1. modified disposable pencil graphite electrode [3] A. Sancar, Chem. Rev. 103 (2003) 2203. (GN/PGE) was used for the construction of the [4] K. Cahová-Kuchaříková , M. Fojta ,T. Mozga, E. [1] biosensing platform for the investigation of the effect of Palecek, Anal. Chem. 77 (2005) 2920. antioxidants on DNA damage. Graphene is a two- 2 [5] M. Fojta, Electroanalysis 14 (2002) 1449. dimensional (2D) carbon-based nanomaterial (sp [6] Y. Yang, J. Zhou, H. Zhang, P Gai, X. Zhang, J. hybridized carbon) which has unique properties such as Chen, Talanta 106 (2013) 206. good thermal, electrical, optical and mechanical [7] J. Wang, Analyst 130 (2005) 421. properties, having high specific surface area and ultrahigh carrier mobility [7]. The invention of graphene has been one of the milestones in nanotechnology. It has been a great potential for various researches such as electrochromic devices, lithium batteries, supercapacitors, solar cells and (bio)sensing devices. Thus, in the current study, graphene provided a convenient interface on the graphite electrode by enhancing the electrochemical properties of the sensing surface, including good electrical conductivity, high electroactive surface area and high mobility transport performance.
Electrochemical detection of the effect of antioxidants was carried out with differential pulse voltammetry (DPV) using different concentrations of ascorbic acid, glutathione and uric acid. The effect of different interaction times were also examined in the study. It was
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0235
Plasma Enhanced Preparation of Graphene/Polyfuran Nanocomposites
Gamze Celik Cogal1,2, Sadik Cogal2, Filiz Kuralay3, Selma Tunc3*, Maria Omastova4, Matej Micusik4, Lutfi Oksuz5 and Aysegul Uygun Oksuz1
1Department of Chemistry, Faculty of Arts and Sciences, Suleyman Demirel University, 32260 Isparta, Turkey 2Department of Polymer Engineering, Mehmet Akif Ersoy University, 15030 Burdur, Turkey 3Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey 4Polymer Institute, Dúbravská cesta 9, 845 41 Bratislava, Slovakia 5Department of Physics, Faculty of Arts and Sciences, Suleyman Demirel University, 32260 Isparta, Turkey
*Presenter: [email protected]
Abstract Graphene is a 2D structure of carbon, which composed of sp2-bonded single-layer carbon atoms with honeycomb lattice. In the recent years, graphene has received increasing attention due to its unique electrical, optical, mechanical and termal and chemical stability properties [1].
Figure 2 RF-rotating plasma system used for preparation of composites
(a) (b) The prepared materials were characterized by using Figure 1 Molecular structure of graphene (a) and fourier transform-infrared spectroscopy (FT-IR), polyfuran (b) scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and electrochemical Conducting polymers (CP) have also attracted measurement. significant importance in different areas due to their ability to prepare polymer materials with similar Acknowledgements: This work has been supported by electrical and optical properties to semiconductors or TUBITAK-114M877 project. even metals. Among CPs, polyfuran is interesting because of its possible technological applications such References as sensors and optoelectronic devices [2]. However, it [1] Z. Yin, J. Zhu, Q. He, X. Cao, C. Tan, H. Chen, Q. has been less studied due to difficulty of synthesis. Yan, H. Zhang, Graphene-based materials for solar cell applications, Adv. Energy Mater., 4 (2014) 1300574. Although CPs exhibit excellent properties, some [2] M. Ates, A review study of (bio)sensor systems properties such as electrical conductivity are not based on conducting polymers, Materials Science and sufficient for some applications and need to be Engineering C, 33 (2013) 1853. developed. One approach is combining the CPs with [3] A. Uygun, L. Oksuz, A.G. Yavuz, A. Guleç, S. Sen, graphene. The combination of the excellent properties Curr. Appl. Phys., 11 (2011) 250. of GR and conducting polymers in composite structures enhanced the electrical conduction and electrocatalytic activity of CPs.
In this study, graphene/polyfuran nanocomposites and polyfuran homopolymers were synthesized using RF- rotating plasma (Fig. 2) [3], which is fast, versatile and environmentally friendly process. During the experiment the plasma chamber was rotated under constant rate for obtaining uniform coating of polyfuran on the surface of graphene. The collected graphene coated with polyfuran was directly characterized without further treatment.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0236
Electrochemical Behavior of Cefuroxime Axetil
on Graphene Oxide Modified Glassy Carbon Electrode
S.Erdoğan Kablan1* and N. Özaltın1
1Department of Analytical Chemisty, Hacettepe University, Faculty of Pharmacy
*Presenter: [email protected]
Abstract The electrochemical oxidation behavior of Cefuroxime Axetil (CEFA) on graphene oxide modified GCE was investigated by voltammetric methods in pH 2 Britton-Robinson buffer. A well-defined peak was observed at 1.30 V vs. Ag/AgCl for electrooxidation of CEFA at modified glassy carbon electrode (M-GCE) by using square wave voltammetry (SWV). Current type, reversibility of electrode reaction and the number of electrons transfered were investigated by using cyclic voltammetry (CV), chronoamperometry (CA) and Figure 2. The Effect of Graphene Oxide Amount on Peak chronocoulometry (CC). Besides the calculation of diffusion Current of 38.0 mg L-1 CEFA in Modification Process coefficient and rate constant of electron transfer, the oxidation mechanism was also proposed. There is no cathodic peak on the cyclic voltammogram of 1.Introduction CEFA and the peak potential shifted to positive values with increasing scan rate, so CEFA oxidation is irreversible on M- Cephalosporins are derived from Cephalosporium which is GCE (Fig. 3). The Slope of (log Ip) vs (log v) graph was species of mushroom. They are antibiotics with a broad obtained 0.1396, which is lower than 0.50 indicates that spectrum of antimicrobial and antibacterial properties and oxidation current of CEFA was diffusion controlled. Because classified into four generations. CEFA is a second-generation of the thin film on modified electrodes, the slope of (log Ip) vs cephalosporin and an oral prodrug formulation of the (log v) decreases from 0.5 to lower values [3]. injectable antibiotic cefuroxime (CEF). Chemical structure of CEFA is shown in Fig. 1. CEFA is the 1-acetoxyethyl ester of CEF. This ester product increases the lipophilicity and the oral bioavailability of the parent compound [1].
Figure 1. Chemical Structure of CEFA Figure 3. Cyclic Voltammograms of 16.13 µg mL-1 CEFA at different scan rates a) Supporting Electrolyte b)25 c)50 d)75 There has not been a method described for the electrochemical e)100 f)250 g)500 mV s-1 behaviors of CEFA using bare glassy carbon electrode (GCE) and graphene oxide modified glassy carbon electrode (M- References GCE). Therefore, the aim of this work was to investigate the electrochemical behaviors of CEFA at M-GCE, and to propose [1] A. Finn, A. Straughn, M. Meyer, J. Chubb, Effect of dose the oxidation mechanism, by using SWV, CV, CA, and CC and food on the bioavailability of cefuroxime axetil, methods. Biopharmaceutics & drug disposition 8 (1987) 519-526. Graphene/graphene oxide has gained technological [2] M. Pumera, Electrochemistry of graphene: new horizons importance in several years [2]. The oxidation peak current of for sensing and energy storage, The Chemical Record 9 (2009) CEFA on bare GCE was too low for investigation (Fig.2). 211-223. Thats why it has been decided to modify the GCE electrode [3] M. Vilas-Boas, C. Freire, B. De Castro, A. Hillman, with graphene oxide to increase the peak current. Electrochemical Characterization of a Novel Salen-Type In this study the peak current (Ip) enhanced for 7-fold, Modified Electrode, The Journal of Physical Chemistry B 102 compared to that bared GCE, in the presence of graphene (1998) 8533-8540. oxide due to the increased surface area and improved electrical conductivity that occured by using graphene oxide modified GCE (Fig.2).
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0237
Electrochemical Studies on the Anti-Parkinson Drug Pramipexole:Square Wave Voltammetric Determination on Graphene Oxide Modified Pencil Graphite Electrode and Investigation of Drug-DNA Interaction
Sevilay Erdoğan Kablan1* and Ceren Yardımcı1
1Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey
*Presenter: [email protected]
1. Introduction guanine oxidation signal monitoring before and after interaction between drug and DNA is used. The DNA Pramipexole is an orally active non-ergoline dopamine was immobilized on a pretreated pencil graphite agonist with selective activity at dopamine receptors electrode by applying a potential at +0.5 V in 0.5 M belonging to the D2 receptor subfamily (D2, D3, D4 acetate buffer solution containing 0.02 M NaCl. The receptor subtypes) and with preferential affinity for the DNA modified pencil graphite electrode was immersed D3 receptor subtype. It is approved as monotherapy in in the blank 0.5 M acetate buffer (pH 4.8) containing early Parkinson’s disease and as adjunctive therapy to 0.02 M NaCl and the oxidation signals of guanine were levodopa in patients with advanced disease experiencing recorded using differential pulse voltammetry. The motor effects because of diminished response to procedure was repeated using a new pencil graphite levodopa [1]. electrode, the electrochemical response of pramipexole was investigated using bare and DNA attached pencil The widespread use of pramipexole and the need for graphite electrode. clinical and pharmacological study require fast and sensitive analytical techniques to assay the presence of 3. Results and Discussion the drug in pharmaceutical dosage forms and also in biological samples. Electroanalytical methods have In this work, we combined the advantages of disposable proved to be useful for development of very sensitive pencil graphite electrode and unique physicochemical and selective methods for the determination of organic properties of graphene oxide. The relationship between molecules, including drugs and related molecules in oxidation peak current and concentration of dosage forms and biological fluids. pramipexole was linear. Validation parameters such as sensitivity, accuracy, precision, and recovery were The interaction of DNA with drugs is an important issue evaluated. The proposed method was employed for in life sciences. The investigation based on DNA quantification of pramipexole in different interactions has great importance in understanding the pharmaceutical formulations. In addition, the DNA mechanism of action of many drug compounds, modified pencil graphite electrode was used in designing of new DNA-drug biosensors and screening combination with differential pulse voltammetry to of the drugs in vitro. Electrochemical DNA biosensors obtain the information about the interaction between enable the study of the interaction of DNA immobilized DNA and pramipexole. on the electrode surface with analytes in solution. References In this study, the voltammetric behavior of pramipexole at a graphene oxide modified pencil graphite electrode [1] M. Dooley, A. Markham, Drugs & Aging, 12 (1998) and at a DNA biosensor is presented. 495-514.
2. Method
The electrochemical behavior of pramipexole was studied over a wide pH range (3.0–10.0) at graphene oxide modified pencil graphite electrode using cyclic and square wave voltammetry. The best definition of the analytical signals was found in Britton Robinson buffer (pH 4.0) at 0.8 V (versus Ag/ AgCl).
The peak current obtained in square wave voltammetry is dependent on various instrumental parameters. The optimized parameters can be summarized as follows: frequency 40 Hz, amplitude 5 mV and pulse size 50 mV.
For investigating the interaction between DNA and pramipexole, differential pulse voltammetry and
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0238
Catechol determination using a novel electrochemical nanobiosensor
S.Kurbanoglu1, 2*, Lourdes Rivas2, Sibel A. Ozkan1 and Arben Merkoçi2, 3
1Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, Ankara, TURKEY 2Nanobioelectronics & Biosensors Group, ICN2- Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain, 3ICREA, Barcelona, Catalonia, Spain
*Presenter: [email protected]
1. Introduction Biosensors have great potential for achieving detect-to- protect devices: devices that can be used in detections of pollutants and other threating compounds/analytes protecting citizens’ life [1]. Enzymes have high affinities toward corresponding substrates being able to catalyze several biochemical reactions without being permanently changed. The recognition system of a biosensor directly depends on the enzyme-substrate relation, which is measured by the Figure 1. SEM images of the designed biosensor. Scale transducer onto which surface enzymes are immobilized bars of SEM images are 200 nm. The SEM images were [2]. obtained using backscatter electrons (BE) mode (right Use of nanomaterials offers to biosensing platforms column) and secondary electron (SE) mode (left exceptional optical, electronic and magnetic properties. column). Nanomaterials can increase the surface of the transducing area of the sensors that in turn increases The analytical characterization of the catalytic behaviors [3]. SPE/CNT/pThi/IrOx/Tyr evaluated by continuous 2. Experimental additions of catechol at different concentrations. A Tyrosinase (Tyr) from mushroom (Z1000 unit/mg), linear response for catechol with r= 0.99 0.2 to 48 µM catechol was purchased from Sigma-Aldrich (St. Louis, was observed. Within 10 s after each addition of MO). As the electrochemical detector, screen printed catechol, sensitive bioelectrocatalytic response reaches carbon electrodes (SPEs) consisted of a set of three about 95% of the steady-state current. Limit of detection electrodes: carbon working electrode with a diameter of (LOD) and limit of quantitation (LOQ) values of the 3 mm, Ag/AgCl pseudo reference electrode (with a developed biosensor were calculated according to the potential of 10 mV with respect to a commercial 3s/m and 10s/m criteria, respectively, where ‘s’ is the Ag/AgCl electrode) and carbon counter electrode with standard deviation of the peak currents of low an approximate thickness of 4 μm were used. concentration of the analyte and ‘m’ is the slope of the In this study, a novel biosensing platform, for the related calibration graph. LOD and LOQ values are also determination of catechol was designed, using carbon calculated as 0.08 and 0.2 µM catechol, respectively. nanotubes (CNTs), polythionine (pThi), Iridium oxide Relative standard deviation (RSD) values were lower nanoparticles (IrOx NPs) and tyrosinase. than 15% for between day repeatability and lower than 3. Results 10% for within-day repeatability [4]. In order to immobilize Tyr, firstly carbon nanotubes are dropped on the surface of the screen printed electrodes. References 0.5 mM Thionine was polymerized on the surface of [1] Thévenot, D. R., Toth, K., Durst, R. A., Wilson, G. S. SPE/CNT between -0.4 V and 0.4 V with 50 mV/s scan (2001). Electrochemical biosensors: recommended definitions rate for 20 cycles in 0.1 M phosphate buffer. 0.25 %, 5 and classification. Biosensors and Bioelectronics, 16(1), 121- µL glutaraldehyde, 5 µL IrOx NPs and Tyrosinase were 131. added to immobilize tyrosinase. [2] Datta, S., Christena, L. R., Rajaram, Y. R. S. (2013). To optimize the amperometric catechol response Enzyme immobilization: an overview on techniques and different number of scans (5-30 CVs), different amount support materials. 3 Biotech,3(1), 1-9. [3] Marín, S., Merkoci, A., Nanomaterials Based of IrOx NPs (1-7 µL) and Tyr (2-10 µL) were studied. Electrochemical Sensing Applications for Safety and Security Scanning Electron Images were obtained to follow the Electroanalysis 2012, 24, No. 3, 459 – 469 surface changes by carbon nanotubes polythionine, [4] S.A. Ozkan, “Electroanalytical methods in pharmaceutical Iridium oxide nanoparticles and tyrosinase (Figure 1). analysis and their validation”, HNB Pub., New York, 2011. Chronoamperometric responses of SPE modified with SPE/CNT/pThi/IrOx/Tyr for continuous additions of 0.2 µM catechol while applying a -200mV potential.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0239
Protein Adsorption and Real Time Cell Analysis of SAM Modified Au Surfaces
S. Eren1*, D. Hür2, L. Uzun3, B. Garipcan1 and Filiz Kuralay4
1 Institute of Biomedical Engineering, Boğaziçi University, 2 Department of Chemistry, Anadolu University, 3Department of Physics, Chemistry, and Biology, Linköping University 4Department of Chemistry, Ordu University
*Presenter: [email protected]
1. Introduction The cell index results of RCTA showed that Ser-SAM modified surfaces have higher viability for cells than Leu- Cell-surface interaction is one of the important topics that SAM modified surface. Leu-SAM modified surfaces have attract attention of researches to investigate effect of surface shown less effect on cell viability as a result of comparison properties on cell behavior. Surface properties, such as with control group. wettability, chemistry, topography and stiffness have effect on cell adhesion. However, it should be considered that protein adsorption is occurred before cell adhesion. Due to this reason, protein adsorption has a key role that affects cell adhesion indirectly [1-3]. In this study, according to these knowledge, protein adsorption and cell studies were run via Quartz Crystal Microbalance (QCM) biosensor and real time cell analyzer (RCTA) to observe effect of surface modifications on protein adsorption and cell adhesion. 2. Materials and Methods In this study, novel amino acid (histidine, leucine, serine, and tryptophan) conjugated SAMs were synthesized in our laboratory, which have special affinity to Au surfaces and attracted by chemisorption [4]. Figure 1 Osteoblast cells and Ser-SAM, Leu-SAM modified Substrates were modified in-situ in flow cell during QCM surfaces interaction real time analysis ,incubated at 37°C, 5% (SRS, CA, USA) frequency measurement. 10mM SAM CO for 48 hours solutions were used for modifications. In addition, water 2 contact angle and XPS analysis were done to prove modifications. References [1] T. Jacobs, R. Morent, N. de Geyter, P. Dubruel, C. Leys, Protein adsorption experiments were run after surface “Plasma surface modification of biomedical modifications with human albumin, fibrinogen for human polymers:Influence of cell-material interaction”, Plasma plasma, and immunoglobulin G via QCM system with Chem Plasma Process, 32, 1039-1073, 2012 different concentrations. [2] E. Psarra, U. König, Y. Ueda, C. Bellmann, A. Janke, E. Bittrich, KJ. Eichorn, P. Uhlmann, “Nanostructured xCellgance (ACEA Bioscienses, Boston, USA, kindly Biointerfaces: Nano-architectonics of Thermoresponsive supplied by ELIPS, Turkey) was used for real time cell Polymer Brushes Impact Protein Adsorption and Cell analysis. Before cell analysis, the Au electrodes of the system Adhesion”, ACS Appl Mater Interfaces, 17, 12516-29, 2015 were modified with SAMs immersing method, and then cell [3] S. Hong, “Quantitative Analysis of Cell-Surface analysis experiment was conducted for 48 hours with Interactions and Cell Adhesion Process in Real-time”, Phd. osteoblast cells. During experiment, cell culture medium and Thesis, Drexel University, 2008 the application of a low voltage create an electric field [4] C.K. Akkan, D. Hür, L. Uzun, B. Garipcan, “Amino Acid between the electrodes, which is called cell index [6]. Conjugated Self Assembling Molecules for Enhancing Surface Wettability of Fiber Laser Treated Titanium Surfaces”, 3. Results and Discussions Applied Surface Science, 366, [5] C. Fornaguera, G. Caldero, M. Mitjans M.P. Vinardell, C. Proteins have significant role in determining the Solans, C. Vauthier, ”Interactions of PLGA nanoparticles with biocompatibility and cell adhesion according to amount, blood components: protein adsorption, coagulation, activation interaction strength, and conformation [5]. Aim of protein of the complement system and hemolysis studies” Nanoscale, adsorption investigation part was manipulation of the protein 7, 6045-58, 2015 adsorption by surface modifications. The surface [6] J.M. Serra, “xCELLigence system for real-time label-free modifications were proved by QCM frequency measurement, monitoring of growth and viability of cell lines from water contact angle measurement, and XPS analysis before hematological malignancies”, Onco Targets Ther, 7,985-994, protein adsorption investigations. 2014 According to results of the protein adsorption study, fibrinogen has shown the highest affinity to Leu-SAM. In addition, Leu-SAM has highest affinity for all proteins than the other SAMs.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0241
Preparation of Poly(thionine) Supported Palladium Nanoparticles For Biosensing Applications
S. Kırlak* and M. Sönmez Çelebi
Department of Chemistry, Faculty of Science and Arts, University of Ordu, 52200, Ordu, Turkey
*Presenter: [email protected]
1. Introduction mM PBS at pH 7.0 in order to record the cyclic voltammogram (CV) of the polymer film (Figure 2). Conducting polymers have been widely studied due to their Oxidation and reduction peaks of the polymer were observed potential applicability in fields like catalysis, electronic at -0.198 V and -0.233 V respectively. When we compare devices and sensor and biosensors design. Their ability to Figures 1 and 2, it is clear that the peak potentials are different enhance electron transfer along with good sensitivity and than that of the monomer stating the formation of PTH. versatility has attracted much interest in the use of conducting polymer films, namely polypyrrole, polythiophene and polyaniline, as suitable matrices for biomolecules immobilisation. For this purpose, the presence of free functional groups, appropriate for the interaction with biomolecules, provide further advantage [1].
Thionine (TH) is a phenothiazine redox dye which can be easily dissolved in water and ethanol. The chemical structure of TH is a small planar molecule with two –NH2 groups symmetrically distributed on each side. Both thionine monomer and the electrogenerated poly-thionine (PTH) have Figure 1 Polymerization profile of TH excellent electrocatalytic activity toward the redox of small molecular compounds. Thionine has been used in many sensor applications [2].
Metal nanoparticles are objects of great interest in modern chemistry and materials research possessing physical as well as chemical properties, which are distinct both from the bulk phase and from isolated atoms and molecules. Metal nanoparticles supported on functional materials have many advantages over unsupported nanoparticles. In connection with metal nanoparticles as the catalytically active moieties, Figure 2 CV of PTH coated GCE the use of functional polymers offers some features, namely: After this step, Pd nanoparticles were incorporated into the it allows the generation of metal nanoparticles with a polymer matrix by bulk electrolysis from 2 mM K2PdCl4 controlled size and size distribution; solution at -0.8 V. It was observed that the so-prepared it provides a mean to influence the chemical behavior of Pd/PTH modified GCE showed excellent catalytic activity the metal nanoparticles through the direct interaction of towards reduction of H2O2 molecule which is involved in the metal surface with the polymer-bound functional several biological events and is the by-product of many groups. enzymatic reactions. So it is concluded that PTH supported Pd The aim of the current study is to prepare a H O sensor based 2 2 nanoparticles can be used to prepare an amperometric H2O2 on palladium (Pd) nanoparticles supported on poly(thionine) biosensor. (PTH). Cyclic voltammetry was used for polymerization of TH from aqueous solution. Pd nanoparticles were immobilized References onto the polymer matrix by bulk electrolysis with coulometry from aqueous K2PdCl4 solution without supporting electrolyte. [1] V. Ferreira, A. Tenreiro, L.M. Abrantes, Sensors and Actuators B, 119, 632 (2006). 2. Experimental [2] A.W. Shi, F.L. Qu, M.H. Yang, G.L. Shen, R.Q. Yu, Sensors and Actuators B, 129, 779 (2008). In electrochemical studies, a glassy carbon electrode (GCE) (r = 1.5 mm) was used as the working electrode. A saturated calomel electrode (SCE) was used as the reference electrode and a Pt wire was used as the counter electrode. Bulk electrolysis with coulometry and cyclic voltammetry studies were carried out with CH Instruments System, Model 600E. 3. Results and discussion PTH was coated onto the GCE surface by cyclic voltammetric scans between -0.4 V and +0.1 V vs. SCE from aqueous solution of TH containing 100 mM phosphate buffer (PBS, pH = 7.0) (Figure 1). PTH coated GCE was then washed with distilled water and placed in a blank solution containing 100
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0242
Electrochemical Impedimetric Immunosensor Based on Gold Nanoparticles Functionalized Screen-Printed Gold Electrode for Carcinoembryogenic Antigen (CEA) Tumor Marker Detection
Ş. Sultan1*, Ç. K. Rabia1 and K. Merve2
1 Department of Bioengineering, Yıldız Technical University, İstanbul, Turkey 2 Department of Medical Biology, Süleyman Demirel University, Isparta, Turkey
*Presenter: [email protected]
Abstract References
Impedimetric immunosensors are constructed with [1] M.I. Prodromidis, Impedimetric immunosensors-A antibody immobilization of working electrode and their review, Electrochimica Acta, 55 (2010) 4227-4233. working principle is that occuring a correlation between [2] M. Taheri, U. Saragovi, A. Fuks, J. Makkerh, J. antigen concentration and obtained resistance after an Mort, C.P. Stanners, Self recognition in the Ig electrochemical Ab-Ag interaction. EIS is generally superfamily - Identification of precise subdomains in used to characterize these type detections in biosensor carcinoembryonic antigen required for intercellular applications [1]. Electrochemical impedimetric adhesion, Journal of Biological Chemistry, 275 (2000) biosensors have significant advantages for sensitive 26935-26943. detection of cancer biomarkers which are being smaller, [3] X.L. Li, R. Yuan, Y.Q. Chai, L.Y. Zhang, Y. Zhuo, Y. faster, more sensitive, cheaper devices, without Zhang, Amperometric immunosensor based on toluidine radiation hazards, allowing label-free, concurrent blue/nano-Au through electrostatic interaction for detection, simple production, less time consuming, rapid determination of carcinoembryonic antigen, Journal of detection, having longer shelf life, and not complicated Biotechnology, 123 (2006) 356-366. procedure. These properties will substantially get easier [4] J. Wu, J. Tang, Z. Dai, F. Yan, H. Ju, N. El Murr, A early dianostic of cancer at beginning phases. disposable electrochemical immunosensor for flow Carcinoembryogenic antigens which are cell surface injection immunoassay of carcinoembryonic antigen, glycoproteins [2] are used as an important biomarker in Biosensors & Bioelectronics, 22 (2006) 102-108. human serum associated with colorectal, lung, breast [5] J. Wang, Electrochemical biosensors: Towards point- cancer and ovarian carcinoma [3, 4]. CEA of-care cancer diagnostics, Biosensors & Bioelectronics, quantification analysis with electrochemical impedance 21 (2006) 1887-1892. spectroscopy promotes early diagnosis of cancer which [6] S.Y. Xu, X.Z. Han, A novel method to construct a is crucial for the successful treatment of the disease and third-generation biosensor: self-assembling gold increases health standards of people[5]. The gold layer nanoparticles on thiol-functionalized poly(styrene-co- has various advantages during immobilization process acrylic acid) nanospheres, Biosensors & Bioelectronics, thereby the easy adsorption of biomaterials relates to 19 (2004) 1117-1120. hydrophobic and thiol–gold interactions. In recent years, [7] D. Hernandez-Santos, M.B. Gonzalez-Garcia, A.C. gold nanoparticles (AuNPs) are commonly used to Garcia, Metal-nanoparticles based electroanalysis, enhance more sensitive electrochemical immunoassay Electroanalysis, 14 (2002) 1225-1235. for immobilization of antibody. AuNPs provide strongly [8] J.M. Pingarron, P. Yanez-Sedeno, A. Gonzalez- adsorbtion of antibody on working electrode during Cortes, Gold nanoparticle-based electrochemical immobilization due to its large specific surface area, biosensors, Electrochimica Acta, 53 (2008) 5848-5866. good biocompatibility, surface free energy of nanosized particles [6, 7]. AuNPs facilitate electron transfer between redox proteins and electrode surfaces, provide effective mass transport in electrochemical biosensor applications as making closer redox protein (monoclonal CEA antibody) to the electrode via nanosized structure. In the other words, AuNPs is a desirable intermediator for immobilization of antibodies [8]. In this study, the gold electrode is modified with thiol and AuNPs to develop an impedimetric biosensor to detect CEA as an important cancer biomarker.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0156
Custom fabricated MEMS-based Microgripper for Biological Cell characterization
T. M. Khan1*, M. Yilmaz1, K. Topalli1, , and N. Biyikli1
1Bilkent University-UNAM, Institute of Materials Science and Nanotechnology, Ankara, Turkey
* Presenter: [email protected]
Abstract The Microgripper is then bonded to a readout circuitry to actively receive sensing output. The microgripper is We present Micro-Electro-Mechanical-Systems initially tested with polymer micro particles to better (MEMS) based microgripper that is used for biological understand the sensing mechanism before characterizing cell characterization. The electrostatically actuated biological cells. microgripper is fabricated using a custom The proposed custom fabrication for MEMS microfabrication process which includes 3 mask microgripper is simple and effective for cell lithographic processes followed by non-conventional characterization. The details of fabrication and jaw release methodology. The microgripper is tested for measurement results will be discussed in the full paper micro-particles ranging from 10-30 µm size and a co- and at the conference. relation is established to further verify its effectiveness in cell characterization using electrostatic comb sensing.
Introduction MEMS-based microgripper is essentially a miniaturized robotic hand. They have a number of applications ranging from pick and place of micro-objects to material characterization. Microgrippers can be actuated or sensed used thermal, electrostatic and magnetic techniques [1]. We use electrostatic comb drive with a common ground to be used as both sensor and actuators. The conventional microfabrication of MEMS devices include SOI-MUMPS (Silicon on Insulator-Multi user MEMS Process) by MEMSCAP Inc. that are patterned from both sides to release the structures and are further diced. This adds a limitation to integration of structures Figure 1 Three pronged jaws to actively hold that are outlying the main chip area. A microgripper for Biological cells. example, requires its jaws to reach out well outside the actuation area to grasp the object. In order to overcome this problem, we add custom patterns that can be scribed off to suspend the jaws. Additionally a three pronged jaw deign is introduced to actively release samples, after manipulation. The jaws are designed to hold cells from 10-30 µm in size. The third beam works as a plunger to remove adhered cells off the jaws to make them usable again (Figure 1) The fabrication process starts with a double side polished SOI wafer with structural layer of 15 µm with 2 µm oxide and 500 µm of handle layer. Initially a lithographic process is made followed by metal deposition using e-beam evaporation and patterned via lift-off for metal bonding. The top layer is then patterned using standard lithography process and Dry etch is achieved to reach the oxide layer (Figure 2). Figure 2 Microgripper with patterned top layer. Wafer is then flipped and back side is patterned using Deep Reactive Ion Etching (DRIE) in Inductively References Coupled Plasma (ICP). The Microgripper is then scribed into smaller dies and then exposed to a Vapor HF [1] Y. Jia and Q. Xu, “MEMS Microgripper Actuators process to remove the underlying silicon dioxide layer. and Sensors: The State-of-the-Art Survey”, Recent In order to release the jaws, we introduced special Patents on Mechanical Engineering 2013, Vol. 6, patterns that are used to scribe off the undesired areas. No. 2
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0243
NO gas sensing properties of CuO nanostructure at low operating temperature
Tuğba Çorlu1*, Irmak Karaduman1, Memet Ali Yıldırım2, Aytunç Ateş3 and Selim Acar1
1 Department of Physics, Science Faculty, Gazi University, Ankara, Turkey 2Department of Electric Electronics Engineering, Engineering Faculty, Erzincan University, Erzincan, Turkey 3Department of Material Engineering, Engineering and Natural Sciences Faculty, Yıldırım Beyazıt University, Ankara, Turkey
*Presenter: [email protected]
Abstract by Successive ionic layer adsorption and reaction (SILAR) method with 15 cycle and investigated the gas Recently, much attention related to health care has been sensing properties. The gas sensing properties of the growing as life expectancy is remarkably extended due CuO nanostructures were measured at different to the advancement of medical treatment and early operating temperatures and depending on different NO diagnosis. As medical technologies develop, individuals and CO concentrations in air. It can be noted that the receive more medical benefits and expect more sample exhibited acceptable response to 1 ppm NO gas convenient ways in diagnosis. According to the recent concentration. The possible sensing mechanism between developments of technology, physical conditions of the producing method and the sensing surface were human body can be easily monitored by analyzing proposed. biomarker gases from human breath [1]. Concentration of these biomarker gases in exhaled breath of the patient are prone to substantial increase compared to that in the breath of healthy people. Among them, NO gas is a critical marker of respiratory diseases [2]; the accurate detection of NO in human breath can give early diagnosis of asthma and lung cancer. Therefore, NO sensors with high sensitivity and fast response are required for environment monitoring, combustion emission control and human health diagnosis. Many efforts have been made to develop NO sensors with good performance [3]. Figure 1 SEM image of CuO film with 15 cycle Among the sensors investigated and developed, CuO based sensors received much attention since they can Acknowledgement: This work is supported by The detect a wide variety of gases with high sensitivity, Scientific and Technological Research Council of Turkey good stability and also low production cost [3]. Copper (TUBITAK) under Project No: 115M658 and Gazi oxide is a well-known p-type semiconductor with a University Scientific Research Fund under Project No: narrow band gap of 1.2 eV and has been extensively 05/2015-09. studied becauseof its versatile applications, such as References catalysts, magnetic storagemedia, gas sensors, lithium batteries, amperometric sensors, etc. Because the [1] A. Rydosz, A. Szkudlarek, Sensors 15, (2015) 20069- practical performances of CuO nanomaterials are close 20085 related to its morphology and size, which ultimately depends on the preparation methods and reaction [2] Y. B. Li, Z. W. Huang, S. Q. Rong, Sensors Materials conditions , various methods have been developed to 18 (2006) 241-249 synthesize CuO nanostructures, for example, thermal oxidation of copperfoil, hydrothermal route, vapor- [3] Z. –X Cai, H. –Y. Li, X. –N. Yang, X. Guo Sens. liquid-solid synthesis, ultra sound irradiation, thermal Actuators B 219 (2015) 346-353 decomposition of precursors, SILAR, etc. [4]. The SILAR method is low cost, simple and suitable for large [4] M. A. Yıldırım, Y. Akaltun, A. Ateş Solid State area deposition. Thin films can be used since the Sciences 141 (2012) 1282-1288 deposition is carried out at or near to room temperature.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0244
Improvement of Immobilization and Spotting Techniques of Biosensors Including Oligonucleotid Probe
Yagmur Guler1*, Mert Muhammed Koc1, Merve Kucukoflaz 1, Şengül Kurtuluş 1, Mehmet Ali Boz1 and Mustafa Oguzhan Caglayan1
1Nanotechnology Engineering Department, Cumhuriyet University, Sivas, Turkey
*Presenter: [email protected]
1.Introduction modeling results with measurement results with DNA microarray technologies have been used in functions with droplets function were compared. molecular biology since 20 years. With the Comparative process was performed on the contact improvement of this technology, the new applications angle values are obtained. This method was carried out techniques like protein microarray techniques, cells on with the contact angle measurements are obtained using chips and comparative genomic hybridization have also different fluids on the Si substrate compared to the been used and new integrated devices like micro total normal measurement process. analysis systems (µTAS) and lab-on-a-chip have been improved. However, these techniques often face some Table 1 The contact angle which was obtained by using reliability problems. In order to use DNA series different fluids and Si substrates values and standard optimally, during the analytical application the actual deviation values (not including modeling) situations and the physicochemical events for each operation must be understood exactly. The most Base Fluid Left Right Average important step during biosensor production is the Material volatilization of the solvent in immobilization step, Si wafer %80 Tripropylene 38.1±2.4 39.4±2.6 38.6±2.6 irrespective of the analytical method being used. During glycol - %20 water Si wafer %40 Tripropylene 59.6±2.6 57.4±2.7 58.2±2.9 volatilization, ODN concentration in the droplet glycol - %60 water increases and as a result, the immobilization kinetics Si wafer %20 Tripropylene 68.9±2.9 69.1±2.8 68.3±2.4 accelerates. During the volatilization of the droplet, by glycol - %80 water dispersion of the ODNs in the droplet/ spot irregularly, Si wafer %10 Tripropylene 78.4±2.8 80.1±2.2 79.1±2.4 glycol - %90 water the cyclic morphology of spot occurs in demilunar or any kind of undesired form. These kinds of Table 2 The contact angle which was obtained by using inhomogenities in and between spots cause errors in different fluids and Si substrates values and standard deviation values(including Young- Laplace modeling) obtaining sensor signals and interpreting the results. The most ideal case is each spot should be similar to Base Fluid Left Right Average immobilized ODN probe and dispersed uniform. Material Si wafer %80 Tripropylene 37.3±1.2 38.1±1.6 37.7±1.1 2.Materials and Methods glycol - %20 water Si wafer %40 Tripropylene 57.3±1.3 57.4±1.7 57.2±1.2 In the presented project, for determining the appropriate glycol - %60 water immobilization conditions, researching the conditions of Si wafer %20 Tripropylene 66.3±0.9 66.1±0.8 66.2±0.6 the spots volatilization on microarrays is being purposed glycol - %80 water Si wafer %10 Tripropylene 76.2±0.8 76.5±1.2 76.1±0.9 considering both the material interactions between glycol - %90 water probe – base and direct adsorption situations. The project were completed by improving the conditions of In this Project results were obtained: Droplet model the immobilization of the probes (ODN and/or protein obtained by solving the equation was used to Young- probe) on to substrate modified by self-assembled Laplace using contact angle measurement on different monolayers which reacts with these different reactive substrates. Droplet model with the measurement results groups by using (micro)spotting techniques; developing obtained contact angle was seen with ow Standard a general mechanism for commercial ODN probes deviation of 2σ’s. There is a significant relationship which are approximately 30 base pair (bp) and between the kinetics of ODN probes immobilized by determination of the general volatilization conditions; contact angle measurements. In studies that use TRIS an improving the volatilization conditions by adding non- PBS buffer solutions which SH functional end on the Au Newtonian fluids (polymeric components and/or surface as stated in the literatre TRIS buffer nanofluids) in the solution forming the ODN probes and immobilization of ODN probes was observed that a researching the volatilization conditions and beter performance. A biolgical agent such as Tween 20, immobilization kinetics; and finally, by providing the the use of immobilization solution increases the most appropriate geometry and spotting conditions for immobilization rate. The effects of nanoparticles, in all non-Newtonian fluids added ODN solutions. the buffer solution may be for interacting with the tertiary structure ODN. The most important output of 3.Results the project, diffirent substrate is also suitable for an After obtaining function using droplets of the Young- improved measurement method. Laplace equation modeling it was performed and the
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0246
Preparation and Characterization of Graphene/Conducting Polymer Composites Coated Surfaces
Yaşar Bayramlı1*, Filiz Kuralay1 and Bora Garipcan2
1Department of Chemistry, Faculty of Arts and Sciences, Ordu University, 52200 Ordu, Turkey 2Institute of Biomedical Engineering, Boğaziçi University, 34684 Istanbul, Turkey
*Presenter: [email protected]
Abstract References [1] F. Kuralay, A. Erdem, Analyst 140 (2015) 2876- Conducting polymers (CPs) are organic polymers that 2880. conduct electricity. They are of quite importance with [2] F. Kuralay, H. Özyörük, A. Yıldız, Sensors and respect to various materials in terms of application since Actuators B: Chemical 109 (2005) 194-199. they have unique electrical and optical properties. These [3] M. Pumera, The Chemical Record 9 (2009) 211-223. polymers have porous structures and high surface areas. [4] B. Pérez-López, A. Merkoçi, Microchimica Acta According to their oxidation states and doped/undoped 179 (2012) 1-16. forms, their volumes change. Thus, conducting polymers are widely used in many areas such as biochemistry, medicine, pharmacy and nanotechnology. Electropolymerization of their monomers result in polymer films, which are uniform and strongly adherent to the electrode surface [1,2].
Graphene (GR) is a single layer of carbon atoms packed into a two-dimensional honeycomb lattice. Graphene- based nanomaterials have drawn considerable interest due to its unique physicochemical, thermal and mechanical properties including large specific surface area, excellent electrocatalytic activity, good electrical conductivity, high mobility of charge carriers and unique transport performance. It has been a great potential for various researches, such as electrochromic devices, lithium batteries, supercapacitors, solar cells and sensing devices [3,4].
In this study, preparation of graphene/conducting polymer nanocomposites coated electrodes were achieved using cyclic voltammetry (CV) and constant potential electrolysis. For the electropolymerization process, pyrrole and 3,4-ethylenedioxythiophene monomers were used. Thus, graphene/polypyrrole and graphene/poly(3,4-ethylenedioxythiophene) coated gold electrode (AuE), platinum electrode (PtE) and glassy carbon electrode (GCE) were obtained. The electrochemical behaviors of the coated surfaces were examined with cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Various cyclic scans and electropolymerization times were used in order to investigate the changes in the electrochemical behaviors of the coated electrodes. We believe that the coated electrodes later on can be used for different applications such as biosensing and biofuel cell applications.
Acknowledgments: F. Kuralay acknowledges Turkish Academy of Sciences (TÜBA) as an associate member and TÜBA-GEBİP programme.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0247
Sensitive Determination of Ceftizoxime by Graphene Oxide/Gold Nanoparticle Modified Pencil Graphite Electrode
Yeşim Tuğçe Yaman1*, Ceren Yardımcı2 and Serdar Abacı3
1 Department of Chemistry, Graduate School of Science and Engineering, Hacettepe University, Ankara, Turkey 2Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey 3Department of Chemistry, Faculty of Science, Hacettepe University, Ankara, Turkey
*Presenter: [email protected]
Figure 1. SEM images of a) Bare PGE, b) GO modified Introduction PGE, c) AuNP modified PGE, d) AuNP/GO modified PGE. (Magnitude: 35000) Ceftizoxime (CFX), is the third generation cephalosporin antibiotic. It interferes the formation of The electrochemical behavior of CFX was investigated the bacterium’s cell wall causing the wall to rupture by cyclic voltammetry (CV) at bare and modified PGE which results the death of bacteria [1]. There are many surfaces. (Figure 1). studies that have been published regarding the detection and analytical control of CFX by chromatographic and spectroscopic methods which are highly sensitive and have low detection limit, they have high costs, a time- consuming process and require trained technicians. Because of these drawbacks in this study, determination of CFX was performed by electrochemical methods.
Method Cyclic voltammetry (CV) was performed for identifying oxidation peak of CFX and to show the effect of modified electrode for the peak current response of Figure 2. Cyclic voltammogram of 50 µM CFX at (a) CFX. Square wave anodic stripping voltammetry bare, (b) GO modified, (c) AuNP modified, (d) (SWASV) was recorded from the 0.6 V to 1.0 V (vs. AuNP/GO modified PGE. (e) blank solution pH 3 BRT. Ag/AgCl) after 300 seconds and 0.6 V (vs. Ag/AgCl) (Scan rate:100 mVs-1) accumulation time and deposition, respectively. Square wave voltammetry parameters were examined. The In Figure 2, after the surface modification with optimized values were amplitude 4 mV, pulse size 50 AuNP/GO, oxidation peak current of CFX was mV, frequency 50 Hz. increased. This result shows the catalytic effect of AuNP/GO surface on the CFX oxidation peak current. Results and Discussion Parameters affecting the experimental conditions, such Surface morphology of bare and modified electrodes as the electrodeposition time of AuNP, physical was performed by scanning electron microscopy (SEM). adsorption time of GO, pH, accumulation time, Fig.1.a shows that bare PGE surface has irregular deposition potential, etc., were investigated for the graphite layer. Because of the GO sheet entangled with maximum performance of the electrode. Under each other, the single- or few-layer GO nanosheets were optimized conditions, the limit of detection and the limit with lots of wrinkles (Fig.1.b). When AuNP was of quantity were found to be 0.4 nM and 1.2 nM for deposited onto the PGE by electrolysis, AuNP was CFX, respectively. This new sensor system offered the formed as spherical structure (Fig.1.c,d). advantages of simple fabrication, low cost, fast response, high sensitivity, low background current and low detection limit for CFX. This new sensor system was successfully tested for the quantitative detection of the CFX in a pharmaceutical preparation.
Acknowledgement: The authors thank to Research Council of Hacettepe University for financially supporting to this study (THD-2015-7394).
References [1] S. Shahrokhian, S. Ranjbar, M. Ghalkhani, Electroanalysis. 28 (2016) 469–476.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0232
Modeling of a Photonic Crystal Fiber Based Dye Laser
Z. Rashida, K. Çiçeka, and A. Kiraza,b*
a Koç University, Department of Physics, Sariyer, Istanbul b Koç University, Department of Electrical and Electronics Engineering, Sariyer, Istanbul
*Preenter:: [email protected]
Abstract
Photonic crystal fiber (PCF) is a new class of microstructured optical devices which confine and guide light by the structural modifications and not only by the refractive index contrast. PCFs are finding applications in highly sensitive gas sensors, biesensors and fiber lasers because of augmented light matter interaction in the transparent core or the neighbourhood. PCF is a promising technology for enhancing the power levels of fluidic lasers because of its increased flexibility in singlemode core sizes, the increased numerical aperture of pump cores in doubleclad fiber configurations and the high thermal stability of lowloss allglass structures. Associated with less bending loss, controlled dispersion and variable group velocity, the use of photonic crystal fibers as host medium for the active biological gain medium to develop a fiber laser opens new prospects due to photobleaching and self healing in the field of biophotonics.
We present a mathematical model of a PCF laser based on coupled first order rate equations incorporating rhodamine B dye as a gain medium in the air cladding region of the suspended core PCF. The mode profile of the pump and signal is examined by finite element method which is used to calculate the effective mode index and pump and signal filling factors. We analyze the behavior of the system under different dopant concentration, length of the fiber, scattering loss at pump and signal wavelengths and input pump power. The parametric study, as a result, computes the threshold pump power, slope efficiency, pump and signal power distribution in both directions, fraction of number of atoms in upper level of the energy state and optimum length.
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0248
Amperometric Uric Acid Biosensor Based on Magnetite Nanoparticles Modified Carbon Paste Electrode
Z.Ö.Erdoğan1*, S.Küçükkolbaşı1, P.E.Erden2 and E. Kılıç2
1Department of Chemistry, Faculty of Science, Selcuk University, 42075 Konya, Turkey 2Department of Chemistry, Faculty of Science, Ankara University, 06100 Ankara, Turkey
*Presenter: [email protected]
Abstract range of the enzyme electrode was 1-1000 μM, detection limit was 1μM and response time was 50 s. Uric acid (2,4,6-trihydroxypurine) is an end product from purine derivatives in human metabolism. Abnormal levels of uric acid in biological fluids is a symptom of many diseases such as gout, hyperuricemia, diabetes, renal disease and Lesch-Nyhan syndrome. Therefore, fast and reliable determination of uric acid in biological fluids is routinely required for diagnosis and treatment. [1]. Various methods, including spectrophotometry, enzymatic testkits, high- performance liquid chromatography, capillary electrophoresis, chemiluminescence and electrochemical techniques, is used for the detection of Figure 2 The mechanism of the biosensor uric acid. Nevertheless, most of these methods are very laborious, expensive, time-consuming and/or complex In conclusion the cost of the biosensor is low and its to perform [2, 3]. Among these methods, especially fabrication process is very simple. The biosensor exhibit electrochemical technique for the determination of uric good operational and storage stability. Therefore, the acid is very interesting, because this technique directly presented biosensor offers a good promise for practical provides real-time and on-line data analysis without applications in real samples. Our future study will be need for pre-seperation process. focused on the the use of the enzyme electrode for uric acid determination in real samples. References:
[1] K. Jindal, M. Tomar, V. Gupta, Biosensors and Bioelectronics 38 (2012) 11-18.
[2] J. Arora, S. Nandwani, M. Bhambi, C.S. Pundir, Anal. Chim. Acta 647 (2009) 195-201.
[3] Erden, P.E., Kılıç, E., Talanta, 107, (2013) 312–323.
Figure 1 Uric Acid In this study, carbon paste enzyme electrode based on Fe3O4 nanoparticles for uric acid determination was fabricated. The carbon paste electrode was prepared by mixing magnetite nanoparticles (Fe3O4), uricase enzyme, graphite powder and paraffin oil and the paste was placed into a teflon electrode body. Electron transfer properties of unmodified and Fe3O4 nanoparticles modified carbon paste electrodes were investigated by cyclic voltammetry.
The voltammetric study indicated that the presence of Fe3O4 nanoparticles results in increased electroactive surface area and enhanced electron transfer. The parameters affecting the analytical performance of the enzyme electrode such as enzyme loading, nanoparticle amount, pH, buffer concentration and working potential were investigated. Analytical characteristics of the presented biosensor were also studied. The working
3rd International Congress on Biosensors, 5-7 October 2016, Ankara Poster Presentation – PP0249
Electrodeposition and Characterization of Cu3Te2Te 2 Thin Films
ZehraYazar Aydın1* and Serdar Abacı2
1Hacettepe University, Graduate School of Science and Engineering, Department of Nanotechnology and Nanomedicine, Ankara, Turkey 2Hacettepe University, Faculty of Science, Department of Chemistry, Ankara, Turkey
*Presenter: [email protected]
voltammogram recorded in 0.1 M H2SO4 (blank Introduction solution) for CuTe deposited at 0.1 V electrolysis (blue)
Today, synthesis of compound semiconductors is both Figure 2 shows the 20°–80° 2θ range of the XRD technologically and scientifically very important pattern of the CuTe nanofilm deposited at 0.2 V onto an because of many applications in the optoelectronic and Au substrate. high efficiency solar cells. Thin chalcogenide films are of particular interest for the fabrication of large area photodiode arrays, solar cells, photoconductors, sensors, etc [1]. This study, Cu3Te2Se2 nanofilms were synthesized using underpotential deposition (UPD) based electrochemical codeposition from the same solution at constant potential.
Method
Cu3Te2Te2 nanofilms were synthesized by the UPD- based electrochemical codeposition technique at room temperature from a solution containing both Cu+2 and + HTeO2 , H2SeO3. Cyclic voltammetry and potential- controlled electrolysis methods were used for the electrochemical characterization. Cu3Te2Se2 thin films Figure 2. XRD pattern of a Cu3Te 2Se2 nanofilm were deposited via potential-controlled electrolysis on deposited onto an Au substrate. Au plate. The synthesized nanofilms were characterized by X-ray diffraction (XRD) and X-ray photoelectron XRD results showed that the Cu3Te2Se2 films are spectroscopy (XPS). crystalline and a single phase (Figure 2). The stoichiometric ratios of the components in the Results and Discussion deposited films were determined via XPS. According to The electrochemical behaviors of Cu, Te, Se and calculations based on the XPS data, the Cu:Te:Se ratio Cu3Te2Se2 system in the UPD and bulk regions were in the deposited films is approximately 3:2:2. investigated on polycrystalline Au electrodes by cyclic voltammetry measurements (Figure 1). Consequently, the synthesis of copper chalcogenides nanofilms using underpotential deposition (UPD) based electrochemical codeposition method can be inexpensively and easily performed under atmospheric conditions without requiring difficult-to-use and expensive equipment.
Acknowledgements: This work was funded by the Scientific and Technological Research Council of Turkey (TUBITAK) under project number 138366
References [1] Sakr, G.B., Yahia, I.S., Fadel, M., Fouad, S.S., Romcevic, N. 2010. Journal of Alloys and Compounds.
507, 557–562. Figure 1. a) Cyclic voltammograms 0.1 M H2SO4 at pH 0.5 on Au electrode. 2 mM CuSO4 (black), 2 mM TeO2 (red) and 0,2 mM SeO2 (green) b) Cyclic
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