BIOSENSORS BASED ON OXIDASES IMMOBILIZED IN VARIOUS CONDUCTING POLYMERS

The electrodeposited organic polymers polypyrrole, poly(N-methylpyrrol e), poly(o-phenylenediamine) and polyaniline are compared as matrices for the immobilization of glucose oxidase in the preparation of ampero metric glucose biosensors. Enzyme entrapment in the polymer layer is o btained by electrodeposition of polymers from solutions of monomers co ntaining dissolved enzyme. For all examined sensors a useful and almos t linear range of response to glucose is observed up to at least 20 mM of glucose. The best sensitivity of response is obtained for a glucos e sensor made of poly(o-phenylenediamine) and polypyrrole. A linear re sponse up to 20 mM glucose is also obtained in flow-injection measurem ents for a glucose/polypyrrole sensor. Poly(o-phenylenediamine) is als o used for satisfactory immobolization of choline oxidase in the prepa ration of a choline sensor, whereas a lactate biosensor has been prepa red by immobilization of lactate oxidase in polypyrrole.