Analytical Sciences

Highly Selective Needle-Type Glucose Sensors Prepared by the Immobilization of Glucose Oxidase on γ-Polyglutamic Acid Film

Mikito YASUZAWA,* Kazuaki EDAGAWA,* Takuya MATSUNAGA,* Hiroki TAKAOKA,*,** and Tomoki YABUTANI*

*Department of Chemical Science and Technology, Institute of Science and Technology, The University of Tokushima, 2-1 Minamijosanjima, Tokushima 770-8506, Japan
**Toyo Precision Parts MFG. Co., Ltd., Kashihara, Nara 634-0836, Japan

Fine needle-type glucose sensors with an outer diameter of less that 0.2 mm were fabricated using a low-cost biodegradable γ-polyglutamic acid (PGA) not only as a glucose oxidase (GOx) immobilizing material, but also as a permselective inner membrane. PGA film was prepared on a cellulose acetate-coated Pt–Ir wire electrode, and GOx was covalently immobilized on its surface using water-soluble carbodiimide. The obtained electrode was practically not affected by the existence of electroactive compounds, and provided long-term stability for approximately one month. It also functioned in horse serum with a good linear relationship between the current and glucose concentrations within the range of 2.8 to 22.4 mM.

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