Protein Blocking Solutions

Non-specific protein interactions between detection reagents and target protein elements can cause unwanted background staining. To minimize this type of interaction, use an appropriate protein blocking reagent:

  • Normal sera — widely used as a general protein block in tissue and cell-based staining. For best results, choose a serum species for blocking that matches the species of the secondary antibody.
  • Carbo-Free Blocking Solution (SP-5040) — for lectin staining or in multiplex IHC applications. Lectins are used for at least one label because this solution does not contain interfering glycoproteins. 
  • BSA (SP-5050) — free of the glycoproteins and impurities present in other grades of BSA that can introduce artifacts or increase background staining. Use in IHC, iCC, IF, blots, and ELISAs.
  • R.T.U. Animal-Free Block and Diluent (SP-5035) — plant-protein derived universal antibody diluent and protein blocking reagent for use in multiplex IHC applications where primaries or secondaries from multiple species are used. This solution does not contain animal immunoglobulins, which may be non-specifically bound by the secondary antibodies.
Prostate without and with R.T.U. Animal Free Block and Diluent used in the blocking step. Both sections are no primary antibody controls with Biotinylated Universal Secondary Antibody, VECTASTAIN® Elite® ABC, and ® Vector DAB Substrate for detection. Note significant toning in section without RTU Animal Free Block and Diluent.