Ruthenium red staining of polyanion containing structures in sections from epoxy-resin embedded tissues

Summary Staining by ruthenium red (0.5 mg/ml in borate buffer at pH = 9.2) has been used for light and electron microscopic visualization of polyanion containing structures in sections from glutaraldehyde-fixed, epoxy-embedded tissues. This staining technique can be applied in a simple and rapid way, showing the reactive cell components with suitable resolution and contrast. Preliminary spectrophotometric studies show the correspondence in absorption characteristics of the dye which is bound to polyanions in situ or in vitro .