Amperometric glucose biosensor based on glucose oxidase encapsulated in carbon nanotube-titania-nafion composite film on platinized glassy carbon electrode

A highly sensitive and selective glucose biosensor has been developed based on immobilization of glucose oxidase within mesoporous carbon nanotube-titania-Nafion composite film coated on a platinized glassy carbon electrode. Synergistic electrocatalytic activity of carbon nanotubes and electrodeposited platinum nanoparticles on electrode surface resulted in an efficient reduction of hydrogen peroxide, allowing the sensitive and selective quantitation of glucose by the direct reduction of enzymatically-liberated hydrogen peroxide at - 0.1 V versus Ag/AgCl (3 M NaCl) without a mediator. The present biosensor responded linearly to glucose in the wide concentration range from 5.0 x 10(-5) to 5.0 X 10(-3) M with a good sensitivity of 154 mA M(-1)cm(-2). Due to the mesoporous nature of CNT-titania-Nafion composite film, the present biosensor exhibited very fast response time within 2 s. In addition, the present biosensor did not show any interference from large excess of ascorbic acid and uric acid.