AMPEROMETRIC GLUCOSE BIOSENSORS BASED ON REDOX POLYMER-MEDIATED ELECTRON-TRANSFER

Electrical communication between the flavin adenine dinucleotide redox centers of glucose oxidase and a conventional carbon paste electrode has been achieved by using electron-transfer relay systems based on polysiloxanes. Six materials for amperometric blosensors are described in which ferrocene and dimethylferrocene electron relays are covalently attached to insoluble siloxane polymers. Sensors containing these polymeric relay systems and glucose oxidase respond rapidly to glucose, with steady-state current responses achieved in less than 10 s. The response to glucose under N2 saturation shows apparent Michaelis-Menten constants, K(M)app, in the range 16-71 mM and limiting current densities, j(max), of 29-275-mu-A/cm2. The dependence of the sensor response on the nature of the siloxane polymer and the type of polymer-bound relay is discussed.