AMPEROMETRIC MICRO-BIOSENSOR ARRAY FOR CHOLINE AND ACETYLCHOLINE BASED ON A GLASSY CARBON ELECTRODE MODIFIED BY PLATINUM-BLACK PARTICLES AND A CO-CROSSLINKED ENZYME SYSTEM

A glassy carbon electrode was first modified by electro-depositing sub-micrometer platinum black particles on the surface. An acetylcholine micro-biosensor array and a choline microbiosensor array were fabricated based on immobilization of acetylcholineasterase-choline oxidase or choline oxidase by cross-linking with glutaraldehyde on the Pt-black/GCE. Significant enhancement in performances of these biosensors was achieved. The chronoamperometric response of the acetylcholine micro-biosensor array gave a linear relation in the range of 29 to 1200µmol/L and a detection limit of 8.7µmol/L acetylcholine. The amperometric response of the choline micro-biosensor array gave a linear relation in the range of 24 to 1000µmol/L and a detection limit of 7.4µmol/L choline. They also possessed very good stability and reproducibility for long-term use.