Biosensors

Sensors have become an integral part of day-today life for the scientific community. It's a device that respond to different physical stimulus like heat, light, sound, pressure, magnetism or movement and transmit an electrical impulse to measure any intrinsic property of the constituent material. Electrochemical sensors are a class of chemical sensors in which an electrode is used as a transducer element in the presence of an analyte. Compared to other sensors, electrochemical sensors are attractive because of their remarkable detection capability, experimental simplicity and low cost. Because of these advantages, they are available commercially and have numerous applications in the field of clinical, industrial and biomedical analysis. Variety of electrochemical sensors have been developed over the years which are suitable for these purposes. Highly sensitive and precise nanomaterials based electrochemical sensors have opened up the possibility of creating novel technologies for the early-stage detection and diagnosis of disease related biomarkers. This is because the attractive properties of nanomaterials have paved the way for fabrication of a wide range of electrochemical sensors that exhibit improved analytical capabilities. Besides, planar electrochemical sensors have vast applications in clinical techniques. Based on film deposition technology, planar electrochemical sensors can be divided into two types. They are thick film sensors and thin film sensors. Screen printed electrodes are examples of thick film technology and microelectrode systems are examples of thin film technology. Also, implantable electrochemical sensors have been developed recently that has the provisions for real-time monitoring of pH, blood gases, electrolytes and some selected metabolites. One classic example is using implantable glucose sensors to monitor the dynamics of blood-glucose levels for treating diabetes. These electrochemical biosensors can be classified as amperometric, potentiometric, conductometric and ion-selective field effect transistor-based sensors. In this report, working principles and applications of these different types of electrochemical sensors will be discussed.

2020

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 (

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

The electrochemical sensors ''biosensors'' was looked at in Science direct, google and all articles based on its applications were chosen.

Nanostructure Science and Technology, 2014

Voltammetry involves the application of a potential that varies with time and the measurement of a current that flows between a working and a reference electrode. Voltammetry can therefore be defined as the exploration of the three-dimensional space that relates to potential, current, and time.1 However, under suitable circumstances, simplified conditions can lead to a unique relation, not involving time, between current and potential; such situation provides the so-called steady-state voltammetry.2

Journal of the Brazilian Chemical Society, 2003

Sensores potenciométricos, amperométricos e condutométricos são sensores eletroquímicos com imensa aplicação nas áreas de meio ambiente, indústria e análises clínicas. O presente trabalho apresenta uma revisão generalizada dos aspectos fundamentais, os desenvolvimento e a contribuição destes sensores na área de química analítica, e reporta alguns aspectos relevantes dos avanços na área de sensores eletroquímicos no Brasil. Potentiometric, amperometric and conductometric electrochemical sensors have found a number of interesting applications in the areas of environmental, industrial, and clinical analyses. This review presents a general overview of the three main types of electrochemical sensors, describing fundamental aspects, developments and their contribution to the area of analytical chemistry, relating relevant aspects of the development of electrochemical sensors in Brazil.

Journal 4 Research - J4R Journal, 2016

A biosensor is an analytical device which converts a biological response into an electrical signal. The term biosensor is often used to cover sensor devices used in order to determine the concentration of substances and other parameters of biological interest even where they do not utilize a biological system directly. Biosensors have become essential analytical tools, since they offer higher performance in terms of sensitivity and selectivity than any other currently available diagnostic tool. With appropriate progress in research, biosensors will have an important impact on environmental monitoring, reducing cost and increasing efficiency. Biosensors represent a rapidly expanding field, at the present time, with an estimated 60% annual growth rate; where major focus is on health care industry. Although there use is unquestionable in the field of agri food, research, security and defence. In this paper various aspects of biosensors have been touched.

Environmental Biosensors, 2011

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.