Osmium tetroxide solution, for electron microscopy, 2% in H2O

Not available outside of the UK & Ireland.

Application

Osmium tetroxide solution has been used as a fixative in electron microscopy.

Biochem/physiol Actions

Osmium tetroxide is also referred to as osmium and is mainly used as a secondary fixative of tissues. The molecule reacts with lipid moieties and is responsible for the oxidation of unsaturated bonds of fatty acids. This reaction adds density and contrast to biological samples. In normal tissues, presence of osmium results in intense black staining which can be viewed by normal eye. In addition, it can be used as a mordant (a molecule which combines with stain or dye at later stages) in electron microscopy, thereby enhancing lead staining.