Figure 7: Identification of proteins separated by gel electrophoresis is limited by the small pore size of the gel, as macromolecular probes for protein analysis cannot permeate the gel. The separated proteins are buried in the polyacrylamide gels and therefore further analysis of proteins or their recovery is cumbersome. However, the proteins can be effectively transferred from the gel to the supporting medium by blotting. The presence of SDS facilitates the migration of proteins. Once out of the gel, the proteins come in contact with the nitrocellulose membrane, which binds the protein very strongly on to the surfaces as a band, thus producing a replica of original gels. A variety of analysis involving immuno-chemical analysis can be carried out for the detection of protein bands.