| Research Abstract |
Oxidoreductases such as glucose oxidase does not directly transfer electrons to conventional electrodes because the distance between their redox centers and the electrode surface exceeds, even on closest approach, the distance across which electrons are transferred at sufficient rates. We showed here the direct electrical communication between the redox center of a large enzyme molecule and a simple metal electrode (glassy carbon, platinum, etc.) established through vanadium (V) oxide and redox polymer [Os(bpy)_2(PVP)_<10>C1]C1 (bpy=bipyridyl, PVP=poly-4-vinylpyridine). As enzymes, Flavo enzymes (glucose oxidase, lactate oxidase, glutamate oxidase), quino enzymes (fructose dehydrogenase, galactose oxidase), and peroxidases were selected in this work. The enzyme was codeposited with the redox polymer and cross-linking reagent on the surface of a electrode. The electron transfer from the reduced active center (ex. FADH_2 of glucose oxidase) in the core of the enzyme to the electrode surface is facilitated via the redox polymer matrix. The characterisation of the sensor in terms of linearity, reproducibility, pH dependence, stability and the response to interfering substances was also carried out. The prepared enzyme sensors responded specifically to each substrate.
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