Principle and Method of Silver Staining of Proteins Separated by Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis

Silver staining is an excellent technique for detecting proteins which are separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis due to its efficiency of detecting proteins present in nanograms. The technique is based on the simple principle that selective reduction of silver into metallic silver occurs at the initiation site in the close proximity of protein molecules. The staining process sequentially consists of protein fixation, sensitization, washing, silver impregnation, and finally development of image. Depending upon the amount of silver incorporated into the protein bands, different color of gel is produced on silver staining. Though different protocols of silver staining exist, the method described here is easy, cheap, reliable, and very sensitive.