Evidence for the functional mechanism of a polypyrrole glucose oxidase electrode

One attractive prospect for the use of conducting polymers in the design of amperometric biosensors is that it has been thought possible to arrange for direct electron transfer between entrapped enzymes and “molecular wires” within the polymer. In this article, we investigate the mechanism of an amperometric enzyme electrode based upon the immobilization of the redox enzyme glucose oxidase (GOD) within the conducting polymer, polypyrrole (Ppy). We present evidence that electron transport between GOD and the electrode surface is due to the electrocatalytical oxidation of hydrogen peroxide, which suggests that if direct electron transfer between the enzyme and Ppy does occur, it is, at best, very inefficient.