A new glucose sensor using microporous enzyme membrane

Abstract

A microporous enzyme membrane attached to a platinum electrode surface forms a new glucose sensor. The enzyme electrode is prepared in three steps: casting the block copolymer containing functional silyl groups into a thin film on a platinum electrode; preparation of the microporous membrane by etching the polymer film; and immobilization of glucose oxidase (GOD) into the microporous membrane. Using the glucose sensor fabricated, current flows generated by the enzymatic oxidation of glucose are measured in aqueous glucose solutions of various concentrations. A linear response is obtained in a wide range of glucose concentration, 8×10 −2-2×10 mmol/l, with a short response time of less than 10 s. The porous membrane attached to the platinum plate has a large surface area (90 m 2/g) to load GOD effectively and possesses carbonyl functions on the micropores to immobilize the enzyme through Schiff-base linkage. Furthermore, the membrane might be directly bound to the platinum electrode surface through the SiOPt bond. These features of the membrane afford rapid and linear responses of the GOD electrode in a wide range of glucose concentrations.