Patent ID: 7632672

Claim:
A composite membrane for an enzyme sensor comprising: an inner membrane layer comprising a restorable polymerizable membrane, the inner membrane layer adapted to function as an interference rejection membrane; an outer membrane layer comprising polyurethane, and adapted to be disposed adjacent a flow channel during use; and an enzyme layer disposed between and in contact with the inner and the outer membrane layers, said enzyme layer comprising a matrix comprising: at least one enzyme selected from the group consisting of glucose oxidase and lactate oxidase; a cross-linking agent; and an enzyme stabilizer selected from the group of polyionic compounds consisting of polyethyleneimine, polypropyleneimine, poly(N-vinylimidazole), polyallylamine, polyvinylpyridine, polyvinylpyrrolidone, polylysine, and protamine; wherein the outer membrane is adapted to control diffusion of an analyte into the enzyme layer.