ABSTRACT
Enzymes have played an important role as analytical reagents in the development of bioelectrodes in the areas of clinical, immunochemical, environmental, and biotechnological analysis. 1,2 Bioelectrodes consist of a biologically active material (e.g., enzyme, antibody, cell fragment, etc.) maintained in close proximity to a suitable transducer that converts the biological signal into an electrical signal. The substrate to be measured diffuses into the biocatalyst layer, where a reaction occurs generating or consuming an electroactive species which can be monitored either potentiometrically or amperometrically. The advantages of bioielectrodes over wet chemical or spectrophotometric procedures are well established. 3 However, considerable effort is still underway to develop reliable, accurate, convenient, low-cost, low-maintenance analyzers. Generally, research is focused on improving either the performance of the biocatalytic element, or the transducer, or both. In the present chapter we describe some of the most widely used immobilization methods and sensors and review several parameters affecting the analytical characteristics of bioelectrodes. Finally, a collection of current analytical applications is presented.
