A Galactose Biosensor Based on the Microfabricated Thin Film Electrode

Abstract

An amperometric biosensor for the galactose measurement was developed by immobilizing galactose oxidase (GAO) on a Nafion-modified thin film platinum electrode. The working electrode with a disk shape and the surrounding ring shaped counter electrode were both fabricated by the thin film technology. They were integrated onto the same microchip. The effects of pH, buffer compositions, and temperature on the biosensor response were investigated. The optimum pH range for the sensor was located between 7.2 to 7.8, and the linear response range was from 0.10 mM to 8.0 mM. The apparent Michaelis–Menten constant value was 29.1 mM. It was observed that some possible interferences from the ascorbic acid, uric acid, sucrose, and glucose were reduced due to the permselectivity of Nafion film. A stable performance of more than one month has been demonstrated on this biosensor.

Keywords:

• Galactose oxidase
• Nafion
• Thin film technology
• Biosensor

Acknowledgments

This work was supported by the Science Foundation of Shanghai Education Commission. The authors thanked the State Key Laboratory of Transducer Technology of Shanghai Institute of Metallurgy, Chinese Academic of Sciences for making the sensor microchips.