Enzyme-modified Langmuir-Blodgett membranes in glucose electrodes based on avidin-biotin interaction

The use of the avidin-biotin interaction has been examined for immobilizing an enzyme on the surface of Langmuir-Blodgett (LB) membranes. Avidin is able to be adsorbed on the LB membrane surface deposited on a tin-doped indium oxide thin film (ITO) electrode, and biotin-labelled glucose oxidase (B-GOD) is immobilized on such an LB membrane surface. Avidin:B-GOD complex (ABC) is also able to be adsorbed on the LB membrane surface and results in a higher current response than that in the above method (bridge method) as the glucose electrode. An increase in the number of deposited monolayers weakens the amperometric response to glucose. A ferrocenyl group-containing LB membrane has also been used to construct a glucose electrode which can be operated at a lower electrode potential. The results are discussed on the basis of the immobilized surface enzyme activities and the function of the LB membranes.