Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Year IX, No2 - 2010 RESEARCH AND ACHIEVEMENTS FOR NEW ELECTROCHEMICAL BIOSENSORS Gheorghe GUTT1, Yarema TEVTUL2, Andrei GUTT1, Alina PSIBILSCHI1 1 Faculty of Food Engineering, Stefan cel Mare University, Street. Universitatii no.13, 720229, Suceava, Romania, [email protected] 2Yuriy Fedkovych National University of Chernivtsi, Kotsiubynsky St., 2, Chernivtsi, 58012 Ukraine Abstract. The paper presents results and research of a team involved in instrumental analysis from Faculty of Food Engineering of Suceava University in biosensors field, for food, health and environment issues. Starting from previous achievements were developed electrochemical performance biosensors, extensive use, for analysis both in situ as well as in the laboratory, mainly in pursuing the universal use of such equipment in all reactions using as catalyst type oxidase enzymes. Another aim was to increase sensitivity of measurement and accuracy of such equipment, also by proposed solutions were removed single-use kits, commonly used in the realization of biosensors by using watertight vials containing oxidase which is enough for hundreds of tests. Combined biosensor described in this paper has the great advantage of using in the amperometric and conductometric methods only their advantages since the two electrochemical methods are complementary, also the dosing system of oxidazes is simple and accurate ensuring a good reproducibility of experimental data. By the avant-garde research and achievements of the team itis opened the way for development of new types of biosensors. Keywords: amperometric and conductometric biosensor, universal biosensor, dual biosensor Introduction. such as: electric charge, absorption / photon emission, temperature, refractive Biosensors are biological-selective index, layer thickness, values that are electronic integrated systems, consisting converted by transducers type of a biological active receiver, a amperometric, pH meters, photometers, transducer and an electronic amplification, thermal, refractive, piezo oscillator, surface processing and display data. Biological plasmon resonance, in proportional active receptor provides specific analytical electrical signals to the concentration of information enabling recognition of certain the species sought in the matter under biological or chemical species in a review. complex mixture that consists matter under Basic applications for biosensors are in review, followed by quantitative or semi- medicine, environmental quality control quantitative determination of it. issue, pharmaceutical industry and Following the interference of biological cosmetics, food industry and in active receptor and analytes resulted biotechnology. Experimental measurement changes of raport between reactants and with biosensors are simple and require no products of the reaction that causes in turn, specialized advanced knowledge but only depending on active biological used the user browsing of short successive systems, proportional evolution of stages in time. physico-chemical measurements values 5 Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Year IX, No2 - 2010 New Methods for achieving detection is a portable glucose biosensors electrochemical amperometric used to determine in situ blood sugar for biosensors diabetics and athletes. Glucose sensor has as an active biological material a Amperometric biosensors are used for the glucosoxidase enzyme used as biocatalysts detection of reaction products or in oxidation reaction of glucose with metabolites that oxidizes or shall slightly oxygen in the air with obtaining reduces. Amperometric method consists in gluconolactone and hydrogen peroxide measuring the electrical current of a (H2O2 -hydrogen peroxide) as products of miniature electrolysis cell electrolysis (this reaction. Biologically active receptor for is a biosensors system), fed at a constant rapid analysis of blood is in the form of voltage. single-use plastic strips that has at one end According to Faraday's law, a mass m of a two miniature plate electrodes between chemical species discharged from an which is deposited glucoseoxidase in a electrode of an electrochemical cell at a form of dry gel that containes a conductive time t is proportional to current I of polymer and at the other end the strip has electrolysis and with electrochemical electrical pine connection with the constant k: electronic system. When submitting a drop of blood on the area covered by the m k I t (1) glucoseoxidase the folowing reaction occurs: Currently, one of the most popular applications in biosensors amperometric D Glu cose O Glucozoxidase Gluconolactone H O 2 2 2 (2) Hydrogen peroxide is highly reactive and polyphenols, flavonoids and for the breaks down at the electrodes of development of substances with electrochemical cell, current intensity of antioxidant activity [3], [4] electrolysis is proportional to the amount Below are listed some typical examples of decomposed and proportional to the biosensors that use different enzymes from amount of glucose in analysed blood . oxidase type, as a catalyst, the result being Such biosensors systems can be used for also hydrogen peroxide obtaining: determining concentration of phenols, Colesterol O ColesteroloxidaseColestenone H O 2 2 2 (3) Glutamate O DGlutamatoxidaseOxiglutarate NH H O 2 3 2 2 (4) Lactate O LactatoxidasePiruvat H O 2 2 2 (5) Piruvat HPO Piruvatoxidase Acetilfosfate CO H O 4 2 2 2 (6) The concerns of analytical instrumental Engineering of Suceava University group from the Faculty of Food focused on improving the amperometric 6 Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Year IX, No2 - 2010 biosensors. Research focused on the In this issue is shown that using following directions: amperometric method, in which 1. achievement a conductometric electrolysis current is also adder, enables biosensor as a superior alternative to reducing the error by limiting electrolysis amperometric biosensors voltage of hydrogen peroxide at the Nernst 2. design and implementation a voltage. conductivity-amperometric biosensor To combine the advantages of both combined with concurrent analysis by both methods and to eliminate the methods, biosensor that can be used in disadvantages of each of them the team has reactions 1-6 using oxidase enzyme as developed a combined biosensor type catalyst conductometric - amperometric [3], [4] for 3. extending limits of concentrations of a the clinical laboratory and analytical food new type of biosensors from maximum In addition to those mentioned this 500mg/dl, as they are encountered in biosensor has a great advantage of not blood, to limit of 20% glucose, the latter working with expensive kits of single-use concentration being specific to analytical but with glucoseoxidase and pure liquid food, particular applications in colesteroloxidase which is precisely fermentative processes dosed[5], [6] using the equipment designed 4. elimination of chemical kit for single by collective use from typical biosensors Starting from the results of theoretical and Research have focused initially only on applied research has been developed a glucose biosensors [1], [2], [4], [6] and portable dual biosensor [7], [8] that allows were mainly intended to find an alternative concurrent determination of both glucose to low reproducibility of typical portable and cholesterol from a single drop of biosensors used to determine blood blood, but it is not the subject of this paper. glucose This low reproducibility is due to Contributions to conception, design and electrolysis phenomenology, electrolysis implementation of combined current, so the indication of glucometer, electrochemical biosensor with superior depending on the addition of hydrogen performance peroxide concentration and other parameters relating primarily to ionic Research team has designed and developed transport phenomena that lead to advanced a prototype of enzyme biosensor that uses electric polarization at electrodes that alter oxidase type enzymes as a catalyst in current yield. liquid form, biosensors being capable of Very promising results obtained in rapid determinations and in situ of experimental research [1], [2] have chemical or biological concentration of confirmed that using conductometric species without using of single-use method with frequency of 5 kHz eliminates biological kits [4 ], [4]. The advantages of the phenomenon of polarization and also using this measurement system are: allows determination both of glucose low - obtaining an universal and reliable concentration, as they are present in blood, biosensor a long-term usable in all types of as well as the concentration at high levels reactions catalyzed by enzymes type up to 20% , specific to analitical food. oxidase Using conductometric method presents - eliminating single-use kits and thereby also a disadvantage, namely that the value significantly lowering of cost price of the of conductivity is an adder for all analysis electrolytical species of blood. - combined use of both amperometric 7 Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Year IX, No2 - 2010 and conductometric method in the same of measurements determinations, it ensure a high a precision Fig.1.Amperometric and conductometric scheme of measurement principle