Polypyrrole, a new possibility for covalent binding of oxidoreductases to electrode surfaces as a base for stable biosensors

Abstract

Preparation and functionalization of conducting polypyrrole films on different materials provide surfaces suitable to bind enzymes covalently after carbodiimide activation. The enzyme electrodes have been tested in comparison to electrodes obtained by binding of oxidases to graphite surfaces. Covalent immobilization of the glucose oxidase directly to the functionalized polypyrrole surface led to biosensors with a short response time, reaching a steady-state current within 30 s in stationary measurements and about 10 s in an automatic flow-injection system. The enzyme electrodes show good stability using oxygen as an electron acceptor, and more than 700 glucose measurements are possible with the new polypyrrole-glucose oxidase electrodes in a flow system.