Hydrogel Viscoelasticity Influences Mechanotransduction and Chondrogenesis of Mesenchymal Stem Cells

Total Page:16

File Type:pdf, Size:1020Kb

Hydrogel Viscoelasticity Influences Mechanotransduction and Chondrogenesis of Mesenchymal Stem Cells HYDROGEL VISCOELASTICITY INFLUENCES MECHANOTRANSDUCTION AND CHONDROGENESIS OF MESENCHYMAL STEM CELLS Matthew Walker (1), Marco Cantini (1) 1. Centre for the Cellular Microenvironment, University of Glasgow, UK Introduction increased early chondrogenesis (SOX9 upregulation Hydrogel stiffness has been long recognised to and RUNX2 downregulation) and late determine human mesenchymal stem cell chondrogenesis (COL2A1 and aggrecan (hMSC) differentiation, whereas viscous upregulation), while preventing an hypertrophic interactions are only recently emerging as powerful phenotype. hMSC behaviour and fate was also regulators of stem cell fate [1, 2]. For example, while influenced by ratios of RGD/HAVDI. Importantly, viscoelastic hydrogels can promote hMSC spreading 3D culture within viscous PEG gels also promoted and proliferation, elastic hydrogels can inhibit cell enhanced chondrogenesis via similar proliferation and, in the case of chondrocytes, limit mechanotransductive mechanisms. cartilage matrix formation [3]. Moreover, hydrogels Discussion can be functionalised with peptide motifs to These novel findings demonstrate that viscous improve hMSC attachment and influence cell fate: interactions both in 2D and 3D can be modulated to for example, chondrogenesis can be controlled by target key mechanotransductive events, leading to peptide gradients using integrin receptor RGD and the activation of chondrogenic pathways in hMSCs cadherin ligand HAVDI [4]. However, as a consequence of substrate viscosity. investigations into how the viscoelastic properties of hydrogels influence the chondrogenic differentiation of hMSCs are lacking. In this work, we investigate whether viscoelastic hydrogels with variable viscous properties and consistent elasticity can provide a cellular micro- environment conducive to the chondrogenic differentiation of hMSCs. Methods Polyacrylamide (PAAM) and polyethylene glycol (PEG) hydrogels were prepared using acrylamide and cross-linker N, N'-Methylene bisacrylamide, or PEG macromers and protease degradable VPM peptide cross-linkers, respectively. Elastic and viscous properties of the hydrogels were measured using AFM and rheology. hMSCs were cultured on RGD/HAVDI-functionalised PAAM hydrogels and within RGD-functionalised PEG hydrogels. Cell cultures were analysed by immunoflourescence Figure 1. A) Sketch and AFM mechanical microscopy and qPCR for adhesion behaviour, as characterization by microrheology (left) and well as markers of mechanotransduction, early nanoindentation (right) of viscoelastic PAAM gels. chondrogenesis, cartilage matrix, and chondrocyte B) Mechanotransduction (quantification of IF of hypertrophy. YAP and nuclear lamins). C) Early chondrogenesis (SOX9) and neocartilage formation (Col II). D) Results Representative IF images of matrix secretion. We prepared viscoelastic PAAM and PEG gels with References different polymer:crosslinker ratios that maintain similar Young’s moduli (~13 kPa), whilst exhibiting 1. Chaudhuri O et al. Nat Mater 15:326, 2016. 2. Cantini M et al. Adv Healthc Mater 1901259, 2019. differences in viscosity (~two-fold loss modulus 3. Lee HP et al. Nat Mater 16:1243, 2017. change), as measured by AFM nanoindentation and 4. Vega S et al. Nat Comm 9, 2018. microrheology, and confirmed by bulk rheology. Acknowledgements 2D culture on PAAM gels functionalised with RGD showed that more viscous substrates prompted The authors acknowledge funding from MRC and decreased hMSC spreading, modulation of adhesion UKRMP (MR/S005412/1). Help and guidance by proteins expression, different mechanotransduction members of the Centre for the Cellular Micro- (decreased nuclear YAP and lamin A/C:B1 ratio), environment is also acknowledged. 26th Congress of the European Society of Biomechanics, July 12-15, 2020, Milan, Italy .
Recommended publications
  • Novel Chitosan–Cellulose Nanofiber Self-Healing Hydrogels to Correlate
    Cheng et al. NPG Asia Materials (2019) 11:25 https://doi.org/10.1038/s41427-019-0124-z NPG Asia Materials ARTICLE Open Access Novel chitosan–cellulose nanofiber self- healing hydrogels to correlate self-healing properties of hydrogels with neural regeneration effects Kun-Chih Cheng1, Chih-Feng Huang2,YenWei3 and Shan-hui Hsu1,4,5 Abstract Biodegradable self-healing hydrogels are attractive materials for tissue repair; however, the impact of the self-healing abilities of hydrogels on tissue repair is not clear. In this study, we prepared novel chitosan–cellulose nanofiber (CS–CNF) composite self-healing hydrogels with the same modulus (approximately 2 kPa) but tunable self-healing properties. By adding a low amount of CNFs (0.06–0.15 wt%) in the pristine chitosan (CS) self-healing hydrogel, the reversible dynamic Schiff bonding, strain sensitivity, and self-healing of the hydrogel are obviously affected. Neural stem cells embedded in the CS–CNF hydrogel with better self-healing properties reveal significantly enhanced oxygen metabolism as well as neural differentiation. The differentiation of neural stem cells is highly correlated with their metabolic change in the self-healing hydrogel. Moreover, the neural regeneration effect of the optimized CS–CNF hydrogel with 0.09 wt% CNFs and the best self-healing properties show a 50% improvement over the pristine CS hydrogel in the zebrafish brain injury model. A mechanism is proposed to interpret the tunable self-healing properties – 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; of CS CNF hydrogels with stiffness maintained in a similar range. The new self-healing hydrogels help to clarify the role of self-healing in the biological performance of hydrogels as well as provide design rationale for hydrogels with better injectability and tissue regeneration potential.
    [Show full text]
  • MEMS Technology for Physiologically Integrated Devices
    A BioMEMS Review: MEMS Technology for Physiologically Integrated Devices AMY C. RICHARDS GRAYSON, REBECCA S. SHAWGO, AUDREY M. JOHNSON, NOLAN T. FLYNN, YAWEN LI, MICHAEL J. CIMA, AND ROBERT LANGER Invited Paper MEMS devices are manufactured using similar microfabrica- I. INTRODUCTION tion techniques as those used to create integrated circuits. They often, however, have moving components that allow physical Microelectromechanical systems (MEMS) devices are or analytical functions to be performed by the device. Although manufactured using similar microfabrication techniques as MEMS can be aseptically fabricated and hermetically sealed, those used to create integrated circuits. They often have biocompatibility of the component materials is a key issue for moving components that allow a physical or analytical MEMS used in vivo. Interest in MEMS for biological applications function to be performed by the device in addition to (BioMEMS) is growing rapidly, with opportunities in areas such as biosensors, pacemakers, immunoisolation capsules, and drug their electrical functions. Microfabrication of silicon-based delivery. The key to many of these applications lies in the lever- structures is usually achieved by repeating sequences of aging of features unique to MEMS (for example, analyte sensitivity, photolithography, etching, and deposition steps in order to electrical responsiveness, temporal control, and feature sizes produce the desired configuration of features, such as traces similar to cells and organelles) for maximum impact. In this paper, (thin metal wires), vias (interlayer connections), reservoirs, we focus on how the biological integration of MEMS and other valves, or membranes, in a layer-by-layer fashion. The implantable devices can be improved through the application of microfabrication technology and concepts.
    [Show full text]
  • Introduction of Microbial Biopolymers in Soil Treatment for Future Environmentally-Friendly and Sustainable Geotechnical Engineering
    sustainability Review Introduction of Microbial Biopolymers in Soil Treatment for Future Environmentally-Friendly and Sustainable Geotechnical Engineering Ilhan Chang 1,†, Jooyoung Im 2,† and Gye-Chun Cho 2,*,† 1 Geotechnical Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology (KICT), Goyang 10223, Korea; [email protected] 2 Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; [email protected] * Correspondence: [email protected]; Tel.: +82-42-350-3622; Fax: +82-42-350-7210 † These authors contributed equally to this work. Academic Editor: Michael A. Fullen Received: 24 November 2015; Accepted: 3 March 2016; Published: 10 March 2016 Abstract: Soil treatment and improvement is commonly performed in the field of geotechnical engineering. Methods and materials to achieve this such as soil stabilization and mixing with cementitious binders have been utilized in engineered soil applications since the beginning of human civilization. Demand for environment-friendly and sustainable alternatives is currently rising. Since cement, the most commonly applied and effective soil treatment material, is responsible for heavy greenhouse gas emissions, alternatives such as geosynthetics, chemical polymers, geopolymers, microbial induction, and biopolymers are being actively studied. This study provides an overall review of the recent applications of biopolymers in geotechnical engineering. Biopolymers are microbially induced polymers that are high-tensile, innocuous, and eco-friendly. Soil–biopolymer interactions and related soil strengthening mechanisms are discussed in the context of recent experimental and microscopic studies. In addition, the economic feasibility of biopolymer implementation in the field is analyzed in comparison to ordinary cement, from environmental perspectives.
    [Show full text]
  • Gelatin-Based Hydrogels for Organ 3D Bioprinting
    polymers Review Gelatin-Based Hydrogels for Organ 3D Bioprinting Xiaohong Wang 1,2,*, Qiang Ao 1, Xiaohong Tian 1, Jun Fan 1, Hao Tong 1, Weijian Hou 1 and Shuling Bai 1 1 Department of Tissue Engineering, Center of 3D Printing & Organ Manufacturing, School of Fundamental Sciences, China Medical University (CMU), No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China; [email protected] (Q.A.); [email protected] (X.T.); [email protected] (J.F.); [email protected] (H.T.); [email protected] (W.H.); [email protected] (S.B.) 2 Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China * Correspondence: [email protected] or [email protected]; Tel./Fax: +86-24-3190-0983 Received: 30 June 2017; Accepted: 8 August 2017; Published: 30 August 2017 Abstract: Three-dimensional (3D) bioprinting is a family of enabling technologies that can be used to manufacture human organs with predefined hierarchical structures, material constituents and physiological functions. The main objective of these technologies is to produce high-throughput and/or customized organ substitutes (or bioartificial organs) with heterogeneous cell types or stem cells along with other biomaterials that are able to repair, replace or restore the defect/failure counterparts. Gelatin-based hydrogels, such as gelatin/fibrinogen, gelatin/hyaluronan and gelatin/alginate/fibrinogen, have unique features in organ 3D bioprinting technologies. This article is an overview of the intrinsic/extrinsic properties of the gelatin-based hydrogels in organ 3D bioprinting areas with advanced technologies, theories and principles. The state of the art of the physical/chemical crosslinking methods of the gelatin-based hydrogels being used to overcome the weak mechanical properties is highlighted.
    [Show full text]
  • Based Thermoresponsive Composite Hydrogels for Biomedical Applications
    polymers Review Poly(N-isopropylacrylamide)-Based Thermoresponsive Composite Hydrogels for Biomedical Applications 1, 1, 2 1 1 1 Xiaomin Xu y, Yang Liu y, Wenbo Fu , Mingyu Yao , Zhen Ding , Jiaming Xuan , Dongxiang Li 3, Shengjie Wang 1 , Yongqing Xia 1 and Meiwen Cao 1,* 1 State Key Laboratory of Heavy Oil Processing and Centre for Bioengineering and Biotechnology, University of Petroleum (East China), Qingdao 266580, China; [email protected] (X.X.); [email protected] (Y.L.); [email protected] (M.Y.); [email protected] (Z.D.); [email protected] (J.X.); [email protected] (S.W.); [email protected] (Y.X.) 2 Heze Key Laboratory of Water Pollution Treatment, Heze Vocational College, Heze 274000, China; [email protected] 3 Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China; [email protected] * Correspondence: [email protected]; Tel./Fax: +86-532-86983455 These authors contributed equally to this work. y Received: 29 December 2019; Accepted: 14 February 2020; Published: 5 March 2020 Abstract: Poly(N-isopropylacrylamide) (PNIPAM)-based thermosensitive hydrogels demonstrate great potential in biomedical applications. However, they have inherent drawbacks such as low mechanical strength, limited drug loading capacity and low biodegradability. Formulating PNIPAM with other functional components to form composited hydrogels is an effective strategy to make up for these deficiencies, which can greatly benefit their practical applications. This review seeks to provide a comprehensive observation about the PNIPAM-based composite hydrogels for biomedical applications so as to guide related research.
    [Show full text]
  • Hydrogel Based Sensors for Biomedical Applications: an Updated Review
    polymers Review Hydrogel Based Sensors for Biomedical Applications: An Updated Review Javad Tavakoli 1,* and Youhong Tang 2,* ID 1 Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide 5042, SA, Australia 2 Institute for Nano Scale Science & Technology, College of Science and Engineering, Flinders University, Adelaide 5042, SA, Australia * Correspondence: javad.tavakoli@flinders.edu.au (J.T.); youhong.tang@flinders.edu.au (Y.T.) Received: 20 July 2017; Accepted: 12 August 2017; Published: 16 August 2017 Abstract: Biosensors that detect and convert biological reactions to a measurable signal have gained much attention in recent years. Between 1950 and 2017, more than 150,000 papers have been published addressing the applications of biosensors in different industries, but to the best of our knowledge and through careful screening, critical reviews that describe hydrogel based biosensors for biomedical applications are rare. This review discusses the biomedical application of hydrogel based biosensors, based on a search performed through Web of Science Core, PubMed (NLM), and Science Direct online databases for the years 2000–2017. In this review, we consider bioreceptors to be immobilized on hydrogel based biosensors, their advantages and disadvantages, and immobilization techniques. We identify the hydrogels that are most favored for this type of biosensor, as well as the predominant transduction strategies. We explain biomedical applications of hydrogel based biosensors including cell metabolite and pathogen detection, tissue engineering, wound healing, and cancer monitoring, and strategies for small biomolecules such as glucose, lactate, urea, and cholesterol detection are identified. Keywords: hydrogel based biosensor; hydrogel; bioreceptors; immobilization; biomedical application; transduction strategies 1.
    [Show full text]
  • Advanced Hydrogels As Wound Dressings
    biomolecules Review Advanced Hydrogels as Wound Dressings Shima Tavakoli 1 and Agnes S. Klar 2,3,* 1 Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran; [email protected] 2 Tissue Biology Research Unit, University Children’s Hospital Zurich, University of Zurich, 75, 8032 Zurich, Switzerland 3 Children’s Research Center, University Children’s Hospital Zurich, 75, 8032 Zurich, Switzerland * Correspondence: [email protected]; Tel.: +41-44-6348-819 Received: 7 May 2020; Accepted: 15 July 2020; Published: 11 August 2020 Abstract: Skin is the largest organ of the human body, protecting it against the external environment. Despite high self-regeneration potential, severe skin defects will not heal spontaneously and need to be covered by skin substitutes. Tremendous progress has been made in the field of skin tissue engineering, in recent years, to develop new skin substitutes. Among them, hydrogels are one of the candidates with most potential to mimic the native skin microenvironment, due to their porous and hydrated molecular structure. They can be applied as a permanent or temporary dressing for different wounds to support the regeneration and healing of the injured epidermis, dermis, or both. Based on the material used for their fabrication, hydrogels can be subdivided into two main groups—natural and synthetic. Moreover, hydrogels can be reinforced by incorporating nanoparticles to obtain “in situ” hybrid hydrogels, showing superior properties and tailored functionality. In addition, different sensors can be embedded in hydrogel wound dressings to provide real-time information about the wound environment. This review focuses on the most recent developments in the field of hydrogel-based skin substitutes for skin replacement.
    [Show full text]
  • 2020.03.10.986315V1.Full.Pdf
    bioRxiv preprint doi: https://doi.org/10.1101/2020.03.10.986315; this version posted March 11, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Hydrogel mechanical properties are more important than osteoinductive growth factors for bone formation with MSC spheroids Jacklyn Whitehead1, Katherine H. Griffin1,2, Charlotte E. Vorwald1, Marissa Gionet-Gonzales1, Serena E. Cinque1, and J. Kent Leach1,3 1Department of Biomedical Engineering, University of California, Davis, CA 95616 2School of Veterinary Medicine, University of California, Davis, CA 95616 3Department of Orthopaedic Surgery, UC Davis Health, Sacramento, CA 95817 Corresponding author: J. Kent Leach, Ph.D. University of California, Davis Department of Biomedical Engineering Davis, CA 95616 Email: [email protected] Author contributions: JW, KHG, CEV: conception and design of experiments, data collection and assembly, data analysis and interpretation, manuscript composition MGG, SEC: conception and design of experiments, data collection and assembly, data analysis and interpretation JKL: conception and design of experiments, data analysis and interpretation, manuscript composition, administrative support bioRxiv preprint doi: https://doi.org/10.1101/2020.03.10.986315; this version posted March 11, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. ABSTRACT Mesenchymal stromal cells (MSCs) can promote tissue repair in regenerative medicine, and their therapeutic potential is further enhanced via spheroid formation. We demonstrated that intraspheroidal presentation of Bone Morphogenetic Protein-2 (BMP-2) on hydroxyapatite (HA) nanoparticles resulted in more spatially uniform MSC osteodifferentiation, providing a method to internally influence spheroid phenotype.
    [Show full text]
  • A Practical Guide to Hydrogels for Cell Culture Steven R Caliari & Jason a Burdick
    REVIEW A practical guide to hydrogels for cell culture Steven R Caliari & Jason A Burdick There is growing appreciation of the role that the extracellular environment plays in regulating cell behavior. Mechanical, structural, and compositional cues, either alone or in concert, can drastically alter cell function. Biomaterials, and particularly hydrogels, have been developed and implemented to present defined subsets of these cues for investigating countless cellular processes as a means of understanding morphogenesis, aging, and disease. Although most scientists concede that standard cell culture materials (tissue culture plastic and glass) do a poor job of recapitulating native cellular milieus, there is currently a knowledge barrier for many researchers in regard to the application of hydrogels for cell culture. Here, we introduce hydrogels to those who may be unfamiliar with procedures to culture and study cells with these systems, with a particular focus on commercially available hydrogels. Introduction: why hydrogels for cell culture? (Fig. 2) since they mimic salient elements of native Our collective understanding of many cell-based pro- extracellular matrices (ECMs), have mechanics similar Nature America, Inc. All rights reserved. America, Inc. Nature cesses is derived from experiments performed on flat, to those of many soft tissues, and can support cell adhe- 6 unphysiologically stiff materials such as polystyrene sion and protein sequestration3. © 201 and glass. Although the simplicity of these platforms Hydrogels have proven useful in a range of cell cul- is attractive, cells cultured in these environments tend ture applications, revealing fundamental phenom- to display aberrant behaviors: flattened shape, abnor- ena regulating cell behavior and providing tools for mal polarization, altered response to pharmaceutical the expansion and directed differentiation of various npg reagents, and loss of differentiated phenotype (Fig.
    [Show full text]
  • Development of 3D Bioprinting Technology Using Modified Natural and Synthetic Hydrogels for Engineering Construction of Organs
    International Journal of Pharmaceutical and Phytopharmacological Research (eIJPPR) | October 2019 | Volume 9| Issue 5| Page 37-42 S. I. Kubanov, Development of 3D Bioprinting Technology Using Modified Natural and Synthetic Hydrogels for Engineering Construction of Organs Development of 3D Bioprinting Technology Using Modified Natural and Synthetic Hydrogels for Engineering Construction of Organs S. I. Kubanov1, S. V. Savina2, C. V. Nuzhnaya1, 3, A. E. Mishvelov1, 3, M. B. Tsoroeva4, M.S. Litvinov5, E. Z. Irugova6, A. Z. Midov6, A. A. Sizhazhev6, L. B. Mukhadieva7, M. V. Savitskaya7, S.N. Povetkin5 1Department of biomedicine and physiology, Federal State Autonomous Educational Institution for Higher Education “North-Caucasus Federal University”, 355017, Russian Federation, Stavropol Region, Stavropol, Pushkina St, 1 2Department of morphology, animals pathology and biology, Federal State Budgetary Educational Institution of Higher Education “Saratov State Agrarian University named after N.I. Vavilov”410012, Russian Federation, Saratov, Teatralnaya Sq, 1 3Laboratory of 3D technologies, Federal State Budgetary Educational Institution of Higher Education “Stavropol State Medical University”, 355017, Russian Federation, Stavropol region, Stavropol, Mira St, 310 4Medical Faculty, Federal State Budgetary Educational Institution of Higher Education North-Western State Medical University named after I.I. Mechnikov, 191015, Russian Federation, Saint-Petersburg, Kirochnaya street, 41 5Department of food technology and engineering, Federal State Autonomous Educational Institution for Higher Education “North- Caucasus Federal University”, 355017, Russian Federation, Stavropol Region, Stavropol, Pushkina St, 1 6Medicine Faculty, Federal State Budgetary Educational Institution of Higher Education “Kabardino-Balkarian State University named after H.M. Berbekov”, 360004, Russian Federation, Kabardino-Balkarian Republic, Nalchik, Chernyshevsky St., 173 7Therapeutic faculty, Federal State Autonomous Educational Institution of Higher Education “I.
    [Show full text]
  • Preparation of Hydrogel Based on Acryl Amide and Investigation of Different Factors Affecting Rate and Amount of Absorbed Water
    Agricultural Sciences, 2017, 8, 161-170 http://www.scirp.org/journal/as ISSN Online: 2156-8561 ISSN Print: 2156-8553 Preparation of Hydrogel Based on Acryl Amide and Investigation of Different Factors Affecting Rate and Amount of Absorbed Water Mostafa A. Radwan, Omar H. Al-Sweasy, Hany A. Elazab* Chemical Engineering Department, The British University in Egypt, BUE, Cairo, Egypt How to cite this paper: Radwan, M.A., Abstract Al-Sweasy, O.H. and Elazab, H.A. (2017) Preparation of Hydrogel Based on Acryl Hydrogel is considered as an important material in our world nowadays as it Amide and Investigation of Different Fac- is used in many important and significant applications such as in tissue engi- tors Affecting Rate and Amount of Ab- neering and agriculture. There are hundreds of types of such materials, where sorbed Water. Agricultural Sciences, 8, 161- 170. most of them can be easily prepared. The main objective of this work is to https://doi.org/10.4236/as.2017.82011 prepare one of the hydrogel types which could be very useful in the agricul- ture of deserts where plants in dry places require water in order to grow up. Received: November 26, 2016 Accepted: February 10, 2017 There are many places around the world where raining occurs only once or Published: February 13, 2017 twice a year. There are also places where it does not rain at all. Therefore, hy- drogels are required in order to absorb water in large quantities either during Copyright © 2017 by authors and raining or irrigation instead of escaping to underground and then eject them Scientific Research Publishing Inc.
    [Show full text]
  • Studying Radiation-Induced Modification of Polymer to Make Water-Superabsorber As a Soil Moisture Conditioner
    VAEC-AR 03-27 VN0500036 STUDYING RADIATION-INDUCED MODIFICATION OF POLYMER TO MAKE WATER-SUPERABSORBER AS A SOIL MOISTURE CONDITIONER Doan Binh*, Phain Thi Tim Hong*, Doan Thi The*, Tran Tich Canh*, Nguyen Quoc Hien*,Vo Thi Kim Lang* and Nguyen Duy Hang** *Reseavch and Development Center for Radiation Technology **Nuclear Research Institute ABSTRACT: Study and preparation of a water-superabsorber based upon polymer in conditioning soil moisture has been carrying out in VINAGAMMA. The capability of absorbing of the water super-absorber is 300 g to 500 g of water per dry gram of hydrogel. The material commonly found in horticultural markets are sold as hydrogel or water super-absorber. Investigation of grafting acrylic acid monomer onto starch (starch-g-AAc) and acrylamide monomer onto carboxymelhyl cellulose (CMC-g-AAm) is first put through. The effect of composition of monomer/substrate of polymer on grafting per cent and on swelling ratio was taken into account. In addition, influence of absorbed dose, rate of absorbed dose, pH, salinity and temperature on swelling ratio was studied. Evaluation of enzymatic degradability of starch-g- AAc and CMC-g-AAm was tested in a-amylaza and cellulaza, respectively. Biodegradation of starch-g-AAc in the soil was also implemented in the greenhouse at 25-28°C. Fresh keeping ability of the sprig of orchid flowers in starch-g-AAc hydrogel was proved better than in the distilled water. As a result, observation of dried/fresh biomass of 'tall shoot" cabbage with or without the hydrogel added in the soil matrix regarding to irrigation regime, distribution in depth of soil layer and ratio of hydrogel/soil was made.
    [Show full text]