Why is Tween 20 added to buffer solutions in IHC?

• A. To denature proteins
• B. To reduce hydrophobic interactions between tissue and reagent proteins
• C. To adjust pH
• D. To act as a chromogen

Answer: (B)

Detergents in buffers are used to cut down non-specific sticking, and Tween 20 serves that role in IHC. Tween 20 is a mild nonionic detergent that coats and disrupts hydrophobic interactions at the tissue–reagent interface. By masking hydrophobic patches on tissue components and on antibodies or other proteins, it reduces non-specific binding and background staining, helping antibodies bind more specifically to their target antigen. It also aids gentle solubilization of lipids and can improve antibody penetration and washing efficiency without destroying antigenicity. This is why it’s included in buffer solutions: to boost signal specificity, not to denature proteins, alter pH, or act as a chromogen.