Development of potentiometric creatinine-sensitive biosensor based on ISFET and creatinine deiminase immobilised in PVA/SbQ photopolymeric membrane

A creatinine-sensitive biosensor was developed using ion-sensitive field-effect transistors (ISFETs) as transducers and immobilised creatinine deiminase (CD) as bioselective element. CD was immobilised by UV photopolymerisation in poly(vinyl alcohol) containing styrylpyridinium (PVA/SbQ) membrane on the dielectric gate of the ISFET transducer. The developed ENFETs demonstrated a dependence of the sensor sensitivity on NaCl and buffer concentration. Minimal detection limit for creatinine determination in a model solution containing 144 mM NaCl and 5% bovine serum albumin (BSA), pH 7.4, was about 20 muM. Biosensor responses were quite reproducible and stable during continuous work at least for 25 h, and the relative standard deviation of the sensor response was approximately 3% (n = 45, for creatinine concentration of 0.1 mM). It was shown that creatinine-sensitive ENFETs demonstrated excellent storage stability for more than 6 months when kept dry at 4-6 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.