A microliter oxygen electrode system for sperm suspensions

A new polarographic oxygen electrode system is described which can accept sperm suspensions with volumes as low as 50 microliters. In this configuration, the electrode tip forms the base of the suspension reaction chamber, and there is no stirring. Consequently, structured fluids such as cervical mucus can be applied. Measurements can be performed in as little time as 10 minutes. The system reliably measures oxygen consumption rates as low as 0.1 mm Hg/minute, so that mammalian sperm suspensions with concentrations of the order 1 X 10(6)viable cells/ml can be applied. Sample experiments, comparing the oxygen uptake of human spermatozoa in semen and in Tyrode's solution, are described.