BIOSENSOR AND ITS APPLICATIONS Compiled by

Analytical Sciences, 2004

The modern concept of biosensors represents a rapidly expanding field of instruments to determine the concentration of substances and other parameters of biological interest since the invention of Clark and Lyons in 1962, for example, created the availability of a rapid, accurate, and simple biosensor for glucose. Biological sensors are analytical devices that detect biochemical and physiological changes. Transducers are essential to convert the particular biological and chemical (biochemical) change into electrical data which can identify different biochemical components of a complex compound to isolate the desired biochemical compounds, for instance, carbon monoxide and sulfur dioxide that contribute to the air pollution. Historically, Clark and Lyons first demonstrated the modern concept of biosensors, in which an enzyme was integrated into an electrode to form a biosensor. The developments of such simple detection tools and similar techniques have made considerable progress since then. Early techniques of biosensors in the analysis of chemical and biological species involved reactions that took place in a solution in addition to catalysts and samples. In recent years, however, the biosensor techniques have provided alternative systems that allowed the reactions without adding reagents to take place at a surface of an electrode. Since the reagents have been already immobilized in the systems, the biological and chemical sensor has performed the task of identifying composition of species with minimum human intervention. The recent improvement of biosensor techniques has continued to depend on and learn from the inefficiency of the early techniques. 1-6 The most common immobilization techniques are physical 1113

Environmental Biosensors, 2011

Journal of Biosensors and Bioelectronics, 2014

The development of chemical sensors has received a great deal of scientific interest in the last decades. Not only the chemical industry may benefit from these sensors but also the food industry, bio-industry, medicine, environmental control because of their capability to give continuously and reversibly a selective and fast response to the presence of a specific compound in a complex mixture of components, without perturbing the system. Biosensors combine the power of analytical detection techniques with the specificity of biological recognition system and therefore they are the most promising devices today about this selectivity. Furthermore, biosensors possess many unique features such as compact size, simplicity of use, one-step reagentless analysis, absence of radioactivity, etc., that make them very attractive alternatives to conventional bioanalytical techniques. The present short review highlights some modern aspects of Chemically Modified Electrodes (CMEs) based on redox enzymes used in amperometric biosensing, a detection method which has already found a large number of applications in health care, food industry and environmental analysis. Some relevant applications of amperometric biosensors based on CMEs to real sample analysis are also presented and some possible future trends highlighted.

Portugaliae Electrochimica Acta, 2009

The goal of this work is the evaluation of the analytical characteristics of the determinations performed using glucose oxidase and acetylcholinesterase based electrochemical sensors, developed applying original or optimized conventional methods of enzyme immobilization. It was found that the sensitivity of glucose determination, for example, varies from 0.048 to 3.36 mA L mol -1 cm -2 and the response time of the glucose oxidase based sensors -from 5 to 30 s, according to the method of the bioreceptor immobilization. The sensitivity of the analysis is affected from the activity of the immobilized biocomponent, from the composition of the solution (concentration of the substrate, of the mediator and of the inhibitor), and from the experimental conditions (pH, temperature, agitation), as well as from the kinetic parameters of the studied process. It was found that the immobilized glucose oxidase conserves its substrate specificity in the presence of a number of glucides (galactose, maltose, fructose, and saccharose) in 100 fold higher concentrations. The selectivity of glucose analysis is ensured applying a suitable potential. Interferences free glucose amperometric determination was performed at 0.00 V/SCE, in the presence of ascorbates and urates. The electrochemical quantification of enzyme inhibitors allows reaching particularly low limits of detection (

Portugaliae Electrochimica Acta

The goal of this work is the evaluation of the analytical characteristics of the determinations performed using glucose oxidase and acetylcholinesterase based electrochemical sensors, developed applying original or optimized conventional methods of enzyme immobilization. It was found that the sensitivity of glucose determination, for example, varies from 0.048 to 3.36 mA L mol -1 cm -2 and the response time of the glucose oxidase based sensors -from 5 to 30 s, according to the method of the bioreceptor immobilization. The sensitivity of the analysis is affected from the activity of the immobilized biocomponent, from the composition of the solution (concentration of the substrate, of the mediator and of the inhibitor), and from the experimental conditions (pH, temperature, agitation), as well as from the kinetic parameters of the studied process. It was found that the immobilized glucose oxidase conserves its substrate specificity in the presence of a number of glucides (galactose, maltose, fructose, and saccharose) in 100 fold higher concentrations. The selectivity of glucose analysis is ensured applying a suitable potential. Interferences free glucose amperometric determination was performed at 0.00 V/SCE, in the presence of ascorbates and urates. The electrochemical quantification of enzyme inhibitors allows reaching particularly low limits of detection (

1998

The development of biosensors started about 35 years ago by the glucose oxidase immobilized platinum electrode for glucose monitoring in blood samples. The attractiveness of such measuring tools is related to their ease of use and accuracy for quick control or continuous on-line monitoring of endogeneous and exogeneous parameters influencing our environment and our health. Currently the original biosensor configuration, though substantially improved in terms of miniaturization, electronics and membrane technology, offers still unsurpassed advantages over "classic" analytical instruments for in vivo analyses (glucose, glutamate, lactate, urea, ...), for on-line bioprocess monitoring, at the physicians'office in patient wards or in hospitals in intense care units, in food, beverages and pollution control etc. At present electrochemical biosensors for various analytes such as lactate, ethanol, fructose, glutamate ... are commercially available. New impetus in biosensor development came about ten years ago by the commercial launching of pen sized devices with single use enzyme based electrode strips. These probes are available for glucose determination in a blood droplet but investigations are aimed to realize similar devices for a great diversity of analytes such as sulfites, cholesterol, peroxides, pesticides, microbes,viruses etc. Actually the above mentioned devices may serve for antibody immobilization on suitable membranes casted on the electrode or directly onto the electrode matrix. Constructors are currently launching antibody or antigen based electrodes for antigen or antibody detection based on competitive or sandwich enzyme linked immunoassays. New generation of amperometric biosensors is under investigation which relies on the direct enzymatic regeneration at the electrode surface. Physical chemistry at the molecular level is required for optimization. The immobilization on the electrode surface of DNA and polynucleic acid chains, membrane like structures and living cells is also under extensive investigation. Remarkable results are being observed for hybridization studies or drug/DNA interaction by potentiometric stripping analysis. Lipidic structures and reconstituted membrane-like bilayers offer interesting conductimetric or impedimetric probes for affinity sensors development. Parallel trends are directed towards multiarray biosensor configurations.

Biosens Bioelectron, 2001

Two Divisions of the International Union of Pure and Applied Chemistry (IUPAC), namely Physical Chemistry (Commission I.7 on Biophysical Chemistry formerly Steering Committee on Biophysical Chemistry) and Analytical Chemistry (Commission V.5 on Electroanalytical Chemistry) have prepared recommendations on the definition, classification and nomenclature related to electrochemical biosensors; these recommendations could, in the future, be extended to other types of biosensors. An electrochemical biosensor is a self-contained integrated device, which is capable of providing specific quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor) which is retained in direct spatial contact with an electrochemical transduction element. Because of their ability to be repeatedly calibrated, we recommend that a biosensor should be clearly distinguished from a bioanalytical system, which requires additional processing steps, such as reagent addition. A device that is both disposable after one measurement, i.e. single use, and unable to monitor the analyte concentration continuously or after rapid and reproducible regeneration, should be designated a single use biosensor. Biosensors may be classified according to the biological specificity-conferring mechanism or, alternatively, to the mode of physico-chemical signal transduction. The biological recognition element may be based on a chemical reaction catalysed by, or on an equilibrium reaction with macromolecules that have been isolated, engineered or present in their original biological environment. In the latter cases, equilibrium is generally reached and there is no further, if any, net consumption of analyte(s) by the immobilized biocomplexing agent incorporated into the sensor. Biosensors may be further classified according to the analytes or reactions that they monitor: direct monitoring of analyte concentration or of reactions producing or consuming such analytes; alternatively, an indirect monitoring of inhibitor or activator of the biological recognition element (biochemical receptor) may be achieved. A rapid proliferation of biosensors and their diversity has led to a lack of rigour in defining their performance criteria. Although each biosensor can only truly be evaluated for a particular application, it is still useful to examine how standard protocols for performance criteria may be defined in accordance with standard IUPAC protocols or definitions. These criteria are recommended for authors, referees and educators and include calibration characteristics (sensitivity, operational and linear concentration range, detection and quantitative determination limits), selectivity, steady-state and transient response times, sample throughput, reproducibility, stability and lifetime.

Analytical Letters, 2001

Two Divisions of the International Union of Pure and Applied Chemistry (IUPAC), namely Physical Chemistry (Commission I.7 on Biophysical Chemistry formerly Steering Committee on Biophysical Chemistry) and Analytical Chemistry (Commission V.5 on Electroanalytical Chemistry) have prepared recommendations on the definition, classification and nomenclature related to electrochemical biosensors; these recommendations could, in the future, be extended to other types of biosensors. An electrochemical biosensor is a self-contained integrated device, which is capable of providing specific quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor) which is retained in direct spatial contact with an electrochemical transduction element. Because of their ability to be repeatedly calibrated, we recommend that a biosensor should be clearly distinguished from a bioanalytical system, which requires additional processing steps, such as reagent addition. A device that is both disposable after one measurement, i.e. single use, and unable to monitor the analyte concentration continuously or after rapid and reproducible regeneration, should be designated a single use biosensor. Biosensors may be classified according to the biological specificity-conferring mechanism or, alternatively, to the mode of physico-chemical signal transduction. The biological recognition element may be based on a chemical reaction catalysed by, or on an equilibrium reaction with macromolecules that have been isolated, engineered or present in their original biological environment. In the latter cases, equilibrium is generally reached and there is no further, if any, net consumption of analyte(s) by the immobilized biocomplexing agent incorporated into the sensor. Biosensors may be further classified according to the analytes or reactions that they monitor: direct monitoring of analyte concentration or of reactions producing or consuming such analytes; alternatively, an indirect monitoring of inhibitor or activator of the biological recognition element (biochemical receptor) may be achieved. A rapid proliferation of biosensors and their diversity has led to a lack of rigour in defining their performance criteria. Although each biosensor can only truly be evaluated for a particular application, it is still useful to examine how standard protocols for performance criteria may be defined in accordance with standard IUPAC protocols or definitions. These criteria are recommended for authors, referees and educators and include calibration characteristics (sensitivity, operational and linear concentration range, detection and quantitative determination limits), selectivity, steady-state and transient response times, sample throughput, reproducibility, stability and lifetime.

Food and Environment Safety Journal, 2017

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.