The Gordon and Sweet's silver staining method is used to demonstrate reticular (retic) fibers. This method relies on the impregnation of retic fibers with silver through oxidation and reduction. The tissue is first oxidized using potassium permanganate to enhance subsequent staining. It is then sensitized using an iron alum solution that targets and binds to the tissue element (retic fibers). The retic fibers are then impregnated by an ammoniacal silver solution that removes and replaces the sensitizer. The silver solution is reduced by 10% formalin so that a visible metallic tone highlights the retic fibers. The metallic silver is then toned and converted to metallic gold using gold chloride solution, thereby providing better chemical stability, fiber contrast, and clarity. Unreduced silver and excess gold are removed via a 5% hypo (sodium thiosulfate) solution. The tissue section may then be counter-stained with nuclear fast-red or light-green.
