High Performance Micro-Enzyme Sensor Using Platinized Microelectrode

A unique micro-enzyme sensor for the determination of glucose has been prepared by incorporating glucose oxidase into the micropores of a platinized microelectrode. The electrode diameter is in the range from 10 μm to 200 μm. The detection limit is 5×10−7 mol L−1 for glucose, and an excellent linearity is obtained in the concentration range from 5×10−7 to 10−2 mol L−1 in the case of micro-enzyme electrode whose diameter is larger than 50 μm. In the case of micro-enzyme electrode whose diameter is 10 μm, the detection limit for glucose is 10−5 mol L−1, and the linearity is observed in the concentration range from 10−5 to 5×10−2 mol L−1. The sensor responds to every glucose sample of different concentration in 3 s or less, and the coefficients of variation for glucose (1 mM) determination were within 2%. The sensor output was stable over 4 weeks. This unique microfabrication approach to micro-enzyme electrodes enables the immobilization of intact enzyme molecules by a simple procedure.