Ligand-mediated osmium binding: Its application in coating biological specimens for scanning electron microscopy

The osmium-bridging properties of thiocarbohydrazide have been used to bind additional osmium to a variety of soft tissue surfaces before critical-point drying. The procedure gives satisfactory protection to specimens under a scanning electron beam at accelerating voltages between 5 and 25 kV and provides the microscopist with a simple, efficient, and economical alternative to evaporative coating with other heavy metals prior to analysis in the scanning electron microscope.