Electrochemical molecular sieving of the polyion complex film for designing highly sensitive biosensor for creatinine

On the basis of our success on creatinine sensor composed of immobilization of creatinine iminohydrolase by polyion complexes (PIC) with a combination of interfacial pH change detection by using inactive polypyrrole film, we investigated various combination of PIC and their sensitivities. The sensitivity of the creatinine sensor was dependent strongly on the distance of the functional units of the anionic species of PIC. The dependence of sensitivity was related to the molecular sieving of the PIC used for the immobilization of the enzyme, i.e., the diffusion of the analytes in the PIC.