Finally , the gold @-@ standard method of cellular localization is immunoelectron microscopy . This technique also use an antibody to the protein of interest , along with classical electron microscopy techniques . The sample is prepared for normal electron microscopic examination , and then treated with an antibody to the protein of interest that is conjugated to an extremely electro @-@ dense material , usually gold . This allow for the localization of both ultrastructural details as well as the protein of interest .