Analysis of individual biochemical events based on artificial synapses using ultramicroelectrodes: cellular oxidative burst

Carbon fiber platinized ultramicroelectrodes placed within micrometres of a single living cell are used to monitor cellular events. This artificial sy napse is used here to collect and examine the very nature of the massive ox idative bursts produced by human fibroblasts when their membrane is locally depolarized by a puncture made with a micrometre sized sealed pipette. The electrochemical analysis of the response indicates that oxidative bursts c onsist of a mixture of a few femtomoles of highly cytotoxic chemicals: hydr ogen peroxide, nitrogen monoxide and peroxynitrite, together with nitrite i ons, which may result from a partial spontaneous decomposition of peroxynit rite prior to its release by the cell.