Fabrication of an ultramicrosensor for measurement of extracellular myocardial superoxide Original Research Article

A novel superoxide (O2−) ultramicrosensor based on copper/platinum microparticles and electropolymerized pyrrole was fabricated for the measurement of extracellular myocardial superoxide. The Cu/Pt-PPy modified ultramicrosensors were evaluated, for the first time, as superoxide sensor. The amperometric response to superoxide was monitored at the potential of 0.45 V (versus saturated calomel electrode (SCE)) in Hank’s balanced salt solution (HBSS). 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 24 nmol/l (S/N of 3). The life period (at least 1 month) of sensors is longer than that of enzyme electrodes. The potential interference from some endogenous electroactive substances in biological tissues, such as hydrogen peroxide (H2O2), uric acid (UA), neurotransmitters and their metabolites, at the concentrations higher than those in biological systems, could be eliminated by further coating the Cu/Pt modified electrode with a polymer film. The method was applied to the measurement of superoxide production in a biologically relevant model system and in rat myocardial cells (MCs).