MICROFABRICATED GLUCOSE, LACTATE, GLUTAMATE AND GLUTAMINE THIN-FILM BIOSENSORS

Glucose, glutamate and lactate oxidase as well as glutaminase were cov alently immobilized on thin-film metal electrodes employing a polyimin e gel obtained by polymerization of amines and aldehydes. The gel matr ix having ion-exchange properties serves an an excellent suppression l ayer for electrochemically interfering compounds. A glutamine sensor w as obtained using the glutamate sensor in combination with highly puri fied immobilized glutaminase from Escherichia coli, pig kidney and Bac illus subtilis. Sensor thus obtained showed rapid response, high stabi lity, excellent suppression of interfering substances and short regene ration time. These sensors were designed for fermentation control in b ioreactors using flow-injection-analysis device (FIA). The sensors wer e also applied for assaying in plasma and whole blood.