Enzyme electrode-based biosensors conductive polymers

In recent years the electrochemistry of the enzyme membrane has been a subject of great interest due to its significance in both theories and practical applications to biosensors (i-5). Since the enzyme electrode was first proposed and prepared by Clark et al. (6) and Updike et al. (7), enzyme-based biosensors have become a widely interested research field. Research efforts have been directed toward improved designs of the electrode and the necessary membrane materials required for the proper operation of sensors. Different methods have been developed for immobilizing the enzyme on the electrode surface, such as covalent and adsorptive couplings (8-12) of the enzymes to the electrode surface, entrapment of the enzymes in the carbon paste mixture (13 etc. The entrapment of the enzyme into a conducting polymer has become an attractive method (14-22) because of the conducting nature of the polymer matrix and of the easy preparation procedure of the enzyme electrode. The entrapment of enzymes in the polypyrrole film provides a simple way of enzyme immobilization for the construction of a biosensor. It is known that the PPy-... 

Conducting polymer-based amperometric enzyme electrodes towards the development of miniaturized reagentless biosensors. Synthetic Metals, 61 (1-2), 31-35. 

Aizawa has studied an enzyme (metal) electrode based on immobilized GOD, which is a redox enzyme [66]. Interfacing in this type of biosensor requires facilitation of electron transfer from the active site of the enzyme protein to the metal electrode. Various methods have been used, such as electron mediators, electron promoters, and molecular wires, to accomplish this purpose. For example, a conducting polymer, polypyrrole, formed by electropolymerization on the electrode surface, was used to form electron wires which can facilitate electron transfers to and from the metal electrode. 

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