Enzyme catalysis at hydrogel-modified electrodes with redox polymer mediator

Abstract

Direct electrical communication between a new acrylamide–acrylic acid ferrocence copolymer and the enzyme cofactor FADH₂ of glucose oxidase is demonstrated. Subsequent catalysis for the anaerobic oxidation of glucose at the co-reticulated enzyme–polymer-modified electrode is shown for polymer-coated glassy carbon and for a composite carbon-paste electrode. A theoretical framework for the kinetic analysis of the reagentless amperometric enzyme electrode is outlined and the model is validated with experimental results. Based on this analysis, kinetic data for the ping-pong glucose oxidase mechanism are discussed for the immobilized enzyme. A comparison of immobilized enzyme electrodes is presented with a redox polymer and soluble substituted-ferrocene redox mediator of similar formal redox potential.