Freeze fracture electron microscopy of a suspension of human sperm cryopreseved in a straw (0.25ml capacity). The cryoprotectant used was glycerol/egg yolk. Ice was nucleated within the straw at -7°C. The sample was then cooled at 10°C per minute to -100°C and then transferred to liquid nitrogen. A cross fracture of the straw followed by deep etching reveals the structure of ice (etched areas) and of the freeze concentrated material (non-etched material). Low power. For higher magnifications of this sample see the next pages.
