En bloc staining available for stereoscopic observation of epoxy resin Quetol 651-embedded thick sections under a...

This method has been devised for easy en block staining for stereoscopic observation of thick sections under a high voltage transmission electron microscope (HVTEM). It uses carbohydrazide as an osmium bridging agent and both osmium tetroxide and uranyl acetate as electron staining agents. Osmium tetroxide-fixed and en bloc-stained tissue blocks are embedded in a Quetol 651 resin mixture. Thick sections (2-3 microns thick) without double staining are observed at an accelerating potential of 300 kV and a tilt angle of +/- 10 degrees by an H-9000 TEM with a side-entry goniometer. Stereoscopic electron micrographs can be obtained.