Markers for immuno-electron microscopy

The development of techniques for electron microscopic studies of biological specimens has made it possible to visualize fine structural details of intact cells in ultrathin sections. The high magnification power of electron microscopes, along with refined techniques for biological specimen preparation, has enabled a wealth of informations with respect to normal and pathological fine structure of organs. Yet, what is usually detected is a map of distribution of electrons scattered by the macromolecular contents of the ultrathin section of the cells. Because spatial and temporal aspects of cellular processes and the functional or evolutionary significance of the complexity of higher organisms cannot be elucidated simply by comparing fine structures, specific detection methods at the molecular level are required for the identification and localization of individual components, quite analogous to light microscopy for which specific stains have been developped which absorb or emit characteristic optical radiation. For the latter, immunohistological stains with fluorochrome or enzyme labelled antibodies have proved most specific and are most generally used. In electron microscopy, such specific stains will have to scatter electrons in characteristic manner.