Stabilizing ultrathin cryo-sections by freeze-drying.

Cryo-sectioning of specimens with high water content often proves to be especially difficult, as the sections of freeze-shocked samples with their minimal thermal capacity warm up easily. The resultant recrystallization of the included water causes considerable damage in the structure of the frozen specimens. The method described in this paper enables cryo-sections to be transferred from the microtome to a precooled high vacuum plant without contamination and at a temperature below the recrystallization point of ice. In this device the cold sections can be stabilized by freeze-drying, sandwiching or electron-bombardment for subsequent observation in the transmission electron microscope.