A POLYPYRROLE 3-ENZYME ELECTRODE FOR CREATININE DETECTION

To detect creatinine, an enzyme electrode was made by co-immobilization of three enzymes, creatininase, creatinase, and sarcosine oxidase, in an active polypyrrole (PPy) matrix. Besides platinum, polypyrrole doped with a sulfated phenoxy resin (S-PHE) was used as a base electrode. The device was fabricated by electropolymerization of pyrrole in the presence of water soluble polyanions, enzymes, and a phosphate buffer, using the above-mentioned base electrodes. At a potential of 400 mV vs Ag/AgCl, the sensors responded to creatinine with a sufficient sensitivity. Under a nitrogen atmosphere, the response current was higher when PPy/S-PHE was used as a base electrode. As a main transduction pathway, a direct electron transfer from sarcosine oxidase to PPy chains is discussed. In addition, the influences of the different polyanionic dopants, the thickness of the active layer, and the concentration of sarcosine oxidase in preparation solutions on the sensor's performance were examined.