Wolf D. Kuhlmann
Division of Radiooncology, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany
The purpose of embedding biological specimens is to replace water by a matrix which is sufficiently stable to maintain cell structures. Furthermore, the tissue block must be penetrable by a cutting device (microtome) to deliver high quality sections (especially thin sections for electron microtomy) which are resistant to the following chemical and staining treatments and to the electron beam in the microscope. For this purpose, several resins can be used, and usually low polarity solvents such as ethanol are employed for dehydration.