Freeze fracture electron microscopy of a cryopreserved human sperm, 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 removes ice and reveals a sperm with its head embedded in freeze concentrated material (non-etched material) with the tail and mid piece extending into the void previously occupied by ice. The flagellum has been fractured during sample preparation.
