Fabrication of an ultramicrosensor for measurement of extracellular myocardial superoxide

A novel superoxide (O-2(-)) ultramicrosensor based on copper/platinum micro particles and electropolymerized pyrrole was fabricated for the measurement of extracellular myocardial superoxide. The Cu/Pt-PPy modified ultramicros ensors were evaluated, for the first time, as superoxide sensor. The ampero metric response to superoxide was monitored at the potential of 0.45 V (ver sus saturated calomel electrode (SCE)) in Hank's balanced salt solution (HB SS). The sensor proved were proved to have a high sensitivity, selectivity and short response time. The detection limit is 24 (DL) of the sensors is 2 4 nmol/l (S/N of 3). The life period (at least 1 month) of sensors is longe r than that of enzyme electrodes. The potential interference from some endo genous electroactive substances in biological tissues, such as hydrogen per oxide (H2O2), uric acid (UA), neurotransmitters and their metabolites, at t he concentrations higher than those in biological systems, could be elimina ted by further coating the Cu/Pt modified electrode with a polymer film. Th e method was applied to the measurement of superoxide production in a biolo gically relevant model system and in rat myocardial cells (MCs). (C)2000 El sevier Science B.V. All rights reserved.