Electrochemical determination of superoxide anions generated from a single neutrophil

The oxidation current of superoxide anions generated from a single neutrophil stimulated with Immunoglobulin G or phorbol myristate acetate has been determined with a carbon fibre microelectrode. Superoxide generation by a stimulated porcine or human neutrophil is initiated 1 min after the stimulation, reaches a maximum around 5 min later, and ends within 20 min. The current—time profiles thus determined agreed well to the time-course curves of superoxide generation obtained from conventional techniques using macroscopic numbers of cells. A sampled dc voltammogram of superoxide anions having a redox potential at around −0.3 V vs. Ag/AgCl was obtained using carbon fibre microelectrode.