Enzyme electrodes with conductive polymer membranes and Langmuir-Blodgett films

A glucose sensor consisting of a conductive polypyrrole membrane and a lipid Langmuir-Blodgett (LB) film has been investigated. Different arrangements of the biosensor on the electrodes examined were (1) electrode with glucose oxidase (GOD)-immobilized lipid LB films; (2) GOD-immobilized LB film coated on polypyrrole-modified electrode; (3) electrode with a GOD-immobilized polypyrrole membrane; (4) GOD-immobilized LB film coated on a GOD-polypyrrole-modified electrode. It was shown that the quality of the biosensor was apparently improved in case (4) with respect to both the detectable concentration range of glucose and the lifetime over which it could be used. The number of layers of the LB film has a marked influence on the sensitivity of the biosensor, an optimum number of layers existing for the best response. The mechanism of such an improvement is discussed.