CATALYTIC BIOSENSORS BASED ON CONDUCTING POLYMERS

摘要

The effective combination of unique properties of biologically active polymers (biopolymers) and physical methods in analytical devices may provide the basis for the direct detection of wide range of analytes..with great sensitivity and specificity. The first conducting polymer, polyacetylene, was discovered by MacDiarmid, Shirakawa, and Heeger. They brought the unique properties of conjugated polymers to the fore in 1977 when they discovered that chemical doping of these materials resulted in increases in electronic conductivity by over several orders of magnitude (1). Since then, electronically conducting materials based on π-π conjugated (conducting) polymers have been applied in a number of diverse applications e.g. sensors, biomaterials, light-emitting diodes, polymeric actuators and corrosion protection agents. Some conducting polymers like polyaniline, polytiophene or polypyrrole are biocompatible and cause minimal and reversible disturbance to the working environment; protecting electrodes from fouling and/or interfering with electrochemically active materials (2). The potential usefulness of these new materials for a wide range of biosensors has been well proven. Such conducting polymers may ultimately be involved with nano-scaling of individual biosensors and the development of so called "Lab on the Chip" systems. Enzymatic biosensors based on polyacetylene, polypyrrole and polyaniline will be reviewed in the light of: (ⅰ) introduction of different subclasses of enzymes in design of amperometric biosensors (3); (ⅱ) the application of various principally different forms of redox mediators - ranging from soluble to wired to polymeric or protein backbone (4); (ⅲ) comparison of immobilization methods (5). Adsorption, covalent attachment and entrapment within conducting polymer backbones will be compared and catalytic biosensor design discussed.