The Strategic Approach

Abstract

In biological electron microscopy (EM), the last fifty years have been largely dedicated to the elucidation of cellular ultrastructural detail. The developmental research that has been needed to resolve cell structure is now part of the history of the subject. Fixation and resin embedding methods for observing structure have been relegated to the routine in most laboratories. The ultrastructural aim is necessarily towards stabilising tissue to protect its structure during the deleterious process of embedding. Embedding tissue in a powerfully crosslinked resin makes it possible to produce the incredibly thin yet strong sections that resist damage caused by an electron beam and provide high resolution. Since the work of Sabatini, Bensch and Barrnett (1963) double fixation with neutral buffered glutaraldehyde and osmium tetroxide has been confirmed to conveniently preserve the finest ultrastructural detail. Dehydration in an organic solvent gradient is then followed by embedding in an epoxy resin. Araldite, for example, is as popular now as it was shortly after the first description of its use by Glauert et al (1956).