Tethered mediator biosensor. Mediated electron transfer between redox enzyme and electrode via ferrocene anchored to electrode surface with long poly(oxyethylene) chain

In order to build an electronic interface between a redox enzyme and an electrode, we have designed a new mediator system, where the mediator molecule is immobilized onto an electrode surface via a long flexible chain-"tethered" mediator. As a prototype tethered mediator system, a ferrocene derivative with a long poly(oxyethylene) chain was immobilized onto an SnO2 electrode and electron mediation function to horseradish peroxidase (HRP) was examined. In the cases of both soluble and co-immobilized HRP, we observed,a catalytic current for hydrogen peroxide reduction. The kinetic analysis exhibited that the tethered ferrocene effectively mediates electron between the enzyme and the electrode. (C) 1999 Elsevier Science S.A. All rights reserved.