| Redox polymers have been made by covalently attaching redox moieties, such as ferrocene, quinone, viologen and phenothiazin to several polymer backbones. Their syntheses and physical properties are described.; Electrode modification of redox polymers can be applied in many applications. For example, the flavin adenine dinucleotide redox centers of many oxidases are electrically inaccessible due to the insulating effect of the surrounding protein, thus, direct electron transfer from the reduced enzyme to a coventional electrode is negligible. In this work, it was observed that a variety of redox polymers can facilitate a flow of electrons from the flavin redox center of glucose oxidase to an electrode. Using experiments involving cyclic voltammetry and stationary potential measurements, it was shown that highly flexible polysiloxane and poly(ethylene oxide) relay systems can rapidly re-oxidize the reduced flavoenzyme. Another observation was found that the hydrophilicity of redox polymers also play an important role for the electron transfer between enzyme and relay system. The construction and response of amperometric biosensor for glucose base on these polymeric materials are described, and the dependence of sensor response on the polymer structure is discussed.; Furthermore, the Toluidine Blue O(3-amino-7-dimethylamino-2-methyl-phenothiazin-5-ium)-modified homopolymer and copolymer have been made for stable and fast amperometric glucose electrodes base on glucose dehydrogenase and nicotinamide adenine dinucleotide (NAD{dollar}sp+){dollar} cofactor. The enzyme-modified electrode can be made by absorbing Toluidine Blue O-containing polymers which previous mixed with glucose dehydrogenase on graphite, and covering a membrane on the electrode. The operating potential of these glucose electrodes was shifted to 0 mV vs. Ag/AgCl, (i.e. the optimal potential range of an amperometric sensor) and the glucose response of the electrodes was shown to be faster than the electrodes based on glucose oxidase. It was also found that the Signal/Noise ratio can be improved due to the low operating potential as well as the low background current. |
