Amperometric ultramicrosensors for peroxynitrite detection and its application toward single myocardial cells

The research studied the concentration variation of peroxynitrite anion (O= N-O-O-) released from cultured neonatal myocardial cells induced by ischemi a/reperfusion and studied the protective effect of melatonin on the injury. For this purpose, amperometry peroxynitrite ultramicrosensors (UMS) were f abricated and constructed by electropolymerizing inorganic macromolecular f ilm of tetraaminophthalocyanine manganese(II) and coating chemically with p oly(4-vinylpyridine). Under optimum conditions, the UMS showed high selecti vity and sensitivity to peroxynitrite determination with a calculated detec tion limit of 1.8 x 10(-8) mol/L (S/N of 3). The detection of peroxynitrite was based on electrocatalytic reduction of peroxynitrite. The mechanism of catalysis was also discussed. The UMS should be promising for in vivo meas urement of peroxynitrite without interference or fouling. Peroxynitrite rel eased from myocardial cells both in the ischemic period and in the reperfus ion period was measured directly. This approach may lead to important infor mation for myocardial cells on the mechanism of injury and prospective trea tments of medicine such as melatonin.