Mesoporous TiO2 films:: New catalytic electrode materials for fabricating amperometric biosensors based on oxidases

A novel catalytic material (mesoporous TiO2 films) for the cathodic detection of hydrogen peroxide in air-saturated aqueous solution is described. The immobilization of glucose oxidase (GOD) as enzyme model onto the TiO2 electrode provides an efficient biosensor for the amperometric detection of glucose at -0.15 V (vs. SCE). GOD molecules were immobilized in an inorganic laponite gel and cross-linked by glutaraldehyde. The highest sensitivity and detection limit were 3.33 mA M-1 cm(-2) and 15 mu M, respectively. In addition different procedures of enzyme immobilization including cross-linking with glutaraldehyde and physical entrapment in a functionalized polypyrrole film have been compared.