Cryotransfer unit
For SEM imaging of fresh, cryofixed tissue in the cryo-mode of the Zeiss Supra 40VP, an Emitech K1250x cryotransfer unit is available. After shock freezing in liquid nitrogen, frozen samples are transferred with the help of a special sample holder into the cylindrical sublimation chamber. Under vacuum, any remaining ice on the sample surface is removed by sublimation. Subsequently, samples are sputtered with a mixture of gold-paladium and directly transferred into the pre-cooled SEM. Using this technique, the quality of sample preparation is usually very high. However, samples are very sensitive and cannot be stored.