Double staining by vaporized osmium tetroxide-hydrazine hydrate of biological specimens for non-coated scanning electron microscopy

Sufficient electron conductivity was obtained in biological specimens following double staining with vaporized osmium tetroxide and hydrazine hydrate for non-gold coated scanning electron microscopic observations. No charging was noted at 25 kV acceleration voltage in rat kidney, liver or other specimens. The foot processes of the glomerular podocytes and micropores of the glomerular endothelium as well as the intracellular endoplasmic reticulum of liver cells were particularly well visualized without the addition of evaporated metal. Repeating this vapor phase osmication method produced even higher contrast at high magnifications compared to the single vaporized osmication method.