Once tissue or cell samples have been appropriately prepared and fixed, the samples are ready to be stained. All IHC/ICC studies are dependent on specific antibody-epitope binding, which is governed by hydrophobic interactions, ionic interactions, hydrogen bonding, and other intermolecular forces. However, the same attractive forces can also result in non-specific staining, i.e. binding of the primary antibody to amino acids other than those within the desired epitope of the antigen. This is a common problem that occurs in IHC/ICC experiments.