Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap.
The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting
qualities, and has several features--low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beaminduced section damage, etc.--which recommends it as a routine embedding
material. The hardness of the cured resin can be easily adjusted by several methods
to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed.
The technique of embedding specimens in epoxy resins for electron microscopy was introduced by Maal0e and Birch-Andersen (1), and markedly improved by Glauert and coworkers (2, 3). Although the method has been used successfully in several laboratories (Birbeck and Mercer (4); Robertson (5), it has failed in others (6). Our
further modifications have been uniformly successful in this and other laboratories where they have been used with a variety of tissues prepared by
several methods of fixation. 1 The newer method employs an epoxy resin of very low viscosity which can be hardened at low temperatures to produce a block with excellent cutting qualities.
Pages : 11
Size: 1.36 mb
Author : HENRY FINCK, Ph.D.
Epoxy Resins in Electron Microscopy