Micro glucose using electron mediators immobilized on a polypyrrole-modified electrode

Abstract

An amperometric micro enzyme electrode for the analysis of glucose is described. Micro gold electrodes fabricated by the sputtering method are used as transducers of micro glucose sensors. Glucose oxidase (GOD) is strongly adsorbed onto a polypyrrole film electropolymerized in aqueous solution. 1,1′-Dimethylferrocene is used as a mediator of electron transfer between adsorbed GOD adn the polypyrrole-modified electrode. Glucose determination within a wide range (2.5 – 30 mM) is possible. The stability of the enzyme electrode has been improved with a lower electrochemical potential (0.1 V versus SCE) over 10 days. By comparison, micro electrodes with a polypyrrole film, which are prepared from an acetonitrile solution of pyrrole, show no response to glucose. Scanning electron microscopy reveals that the surface area of the polypyrrole film prepared in KCl aqueous solution is much larger than that in acetonitrile solution.