chemical fixation

Chemical fixation is a technique to fix a specimen with chemicals to prevent autolysis by the action of enzymes and deformation of morphologies during specimen preparation.  Biological tissues start autolysis caused by their enzymes immediately after stopping the activities of them. For the TEM observation of a biological specimen, the specimen must be prepared by removing water to preserve its morphologies under vacuum in the microscope column, and by thinning the specimen to transmit an electron beam.  For these requests, dehydration, resin embedding and thin sectioning are applied, but the procedures cause deformation of fine structures of the specimen. Chemical fixation is carried out to preserve the morphologies and physical properties at the living states of the specimen as much as possible.  This technique prevents the autolysis and deformation by cross-linking the proteins or lipids of biological materials using chemicals.  Chemical fixation for a TEM is performed by the two steps, prefixation and postfixation.

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