Electrochemical medical biosensors

Enzymes have been widely used as biorecognition elements in biosensors as they are able to catalyze reactions that produce electrochemical, optical, and thermal sig-nals." " Most popularly, glucose oxidase is widely used in electrochemical glucose biosensors that have found wide usage in clinical and medical settings. Enzymes offer ease of immobilization on transducers by physical adsorption, covalent linkage, and... 

Electrochemical transducers have received considerable attention in DNA detection. Electrochemical DNA biosensors have been widely developed for chemical, biochemical, medical, agricultural, and environmental monitoring because of their compact size, real-time analysis, nearly reagentless operation, simple pretreatment protocols, low cost of construction, and simplicity of use. ° ... 

Construction principles and the mechanism for biosensors derived from enzymes. Combined enzymatic and electrochemical reactions proceeding on electrodes from various materials in electrolyte solutions promote development of many biosensor types for detection of glucose, amino acids, lactose, urea, pyruvate and other metabolites. Biosensors are successfully applied to environmental contamination control, medical diagnostics and the food industry. 

As depicted in Figure 1.16, (electrochemical) biosensors are either placed in laboratory animals for fundamental (patho-) physiological and neurochemical in vivo measurements or implanted in the human body for health check purposes and metabolite monitoring. In the field of in vivo medical research, enzyme-based... 

An alternative approach to the intrinsic DNA electrochemical activity utilizes electroactive species as redox indicators of the presence of immobilized DNA as well as its interaction events such as hybridization, damage, and association with another substance [14]. This mode was also used in a pioneering work on the DNA biosensor used for sequence detection [7]. In this case, it is still a label-free method in the sense that DNA probes or targets are not chemically modified by a special label however, as the indicator has to be added to a test S5 em as an additional reagent, we cannot speak more about the reagent-less technique. Redox indicators typically possess electrochemical responses at a "safe" electrode potential and often reversibly. The terms redox probe and redox marker are sometimes used in the literature to mean the redox indicator, which is confusable with the DNA capture probe used as a recognition element at hybridization and with markers used in medical diagnostics [8]. 

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