Incorporation of glucose oxidase into Langmuir-Blodgett films based on Prussian blue applied to amperometric glucose biosensor

Glucose oxidase (GOx) was immobilized in the organic-inorganic Langmuir-Bldogett (LB) films consisting of octadecyltrimethylammonium (ODTA) and nanosized Prussian blue (PB) clusters. The amperometric glucose biosensors based on the LB films were fabricated and tested. It was found that the sensors exhibited a clear response current under an applied voltage of 0.0 V (vs Ag/AgCl). The linearity of current density versus glucose concentration was confirmed below 15 mmol/L concentration. This is the first observation of biosensor function of the hybrid organic-inorganic LB films. The successful preparation of glucose sensors operating at the very low potential indicates that the adsorbed PB clusters in the LB films act as an electrocatalyst for the electrochemical reduction of hydrogen peroxide, which is the final product of the enzymatic reaction sequence. The observed low potential applicability is estimated to inhibit the responses of interferants such as ascorbic acid, uric acid, and acetominophen. It was also found that an electrostatic interaction between positively charged ODTA+ and the adsorbed species of both GOx and PB provided a stabilized adsorption state in the LB films. Such stable immobilization contributes to the steady amperometric response current observed in the present ODTA/PB/GOx LB films.