Division of Radiooncology, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany
The cryostat technique is an alternative to paraffin histology. Cryotechniques are a group of related procedures for the stabilisation of biological specimens for microscopic observations. Tissue samples (lightly fixed or not and cryoprotected) are frozen to maintain morphological structure and composition as it exists under physiological conditions. Thus, cryopreserved samples exhibit the best antigenicity which is often essential for successful immunohistology. Apart from the different cryotechniques for light microscopy, we have to mention cryotechniques for electron microscopy which include cryo-ultramicrotomy, cryo-substituition and cryo-electron microscopy. The latter enables the observation of biomolecules, cells and tissues in their native state without fixation or staining. A typical application is called frozen hydrated transmission electron microscopy.