Immobilization of creatinine deiminase on a substituted poly(methylglutamate) membrane and its use in a creatinine sensor

A substituted poly(γ-methyl-l-glutamate) membrane is used for chemical immobilization of creatinine deiminase. The permeability of the membrane is controlled by the conditions used for membrane preparation. The creatinine sensor based on the immobilized enzyme membrane with immobilized nitrifying bacteria and an oxygen electrode exhibited greater sensitivity than the sensor previously reported which had a 1,8-diamino-4-amino-methyloctane membrane. The sensor gave a linear response to creatinine over the range 1–10 mg dl^?1; responses remained stable for two weeks.