Modified electrode surface in amperometric biosensors

The electron transfer reactions of biological molecules are frequently very slow at ordinary electrodes. To overcome this problem, and thus to facilitate the direct coupling of biological redox reactions to electrodes for biosensor or bioelectronic applications, various types of modified electrode have been used. These include electrodes modified by the covalent attachment of species to the surface, by the reversible adsorption of promotors, or by the deposition of polymeric species, and the use of conducting polymers or conducting organic salts as electrode materials. Some of these different approaches are reviewed and their applications to biosensors and bioelectrochemistry are discussed.