The transmission electron microscope (TEM) is a valuable tool in biomedical sciences at the subcellular morphological examination. Moreover, can be localized with antibodies specific proteins (immunofluorescence labeling). Usually samples are chemically fixed, dehydrated, embedded in rosin, cut and contrasted. This chemical fixation may induce structural changes, and provide for a displacement of soluble proteins. Moreover complicate embedding the use of antibodies. The best way to preserve the cellular structure Cryofixation through high pressure freezing. This is followed by freeze-substitution wherein the ice in the frozen steel is replaced by rosin. The samples can then be cut and contrasted at room temperature. The rosins mortgage still using antibodies. An alternative is the Tokuyasu technique in which, after a mild chemical fixation, the sample is deep-frozen and sliced ​​with a cryo-ultramicrotome. These frozen sections are thawed, after which immuno-labeling can be performed. Finally, the sections can be studied with an ultramodern 120 kV TEM.