BIFUNCTIONAL LANGMUIR-BLODGETT-FILM FOR ENZYME IMMOBILIZATION AND AMPEROMETRIC BIOSENSOR SENSITIZATION

A Langmuir-Blodgett (LB) film consisting of octadecylamine as the binding site for the enzyme molecule, an amphiphilic ferrocene derivative as the electron mediator, and octadecanol as the matrix for these molecules was deposited on a hydrophobized tin oxide (SnO2) electrode. Glucose oxidase (GOx) was then covalently immobilized on the film via glutaraldehyde, and the GOx electrode thus obtained worked as an amperometric glucose sensor based on the oxidation of hydrogen peroxide liberated by the enzymatic reaction. The sensitivity of this sensor was about twice as high as that of a GOx electrode prepared with the same LB film as above but without the ferrocene. The sensitizing effect of ferrocene was attributed to its capability of electron mediation between hydrogen peroxide and the SnO2 electrode.