A fast and sensitive potentiometric glucose microsensor based on glucose oxidase coated ZnO nanowires grown on a thin silver wire

In this study, a potentiometric glucose biosensor was fabricated by immobilization of glucose oxidase on to zinc oxide nanowires. Zinc oxide nanowires with 250–300 nm diameters and approximately 1.2 μm lengths were grown on the surface of silver wires with a diameter of 250 μm. Glucose oxidase (GOD) was electrostatically immobilized on the surface of the well aligned zinc oxide nanowires resulting in sensitive, selective, stable and reproducible glucose biosensors. The potentiometric response vs. Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (0.5–1000 μM) suitable for intracellular glucose detection. By applying a membrane on the sensor the linear range could be extended to 0.5 μM to 10 mM, which increased the response time from less than 1 to 4 s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents with glucose sensing such as uric acid and ascorbic acid.