Tris-buffered saline (TBS): Composition and applications

What is Tris-buffered saline (TBS)?

Tris-buffered saline (TBS) is an aqueous buffer solution containing Tris(hydroxymethyl)aminomethane (Tris) and sodium chloride (NaCl). The Tris component acts as a pH buffer, stabilising the solution within a physiological range—commonly pH 7.4 to 8.0—making it ideal for biological applications. TBS is frequently used in washing steps during techniques such as Western blotting, ELISA, and immunohistochemistry, where maintaining protein structure and preventing non-specific binding is critical.

How is TBS used in laboratory workflows?

In laboratory settings, TBS is often supplemented with detergents like Tween-20 (forming TBS-T) to reduce background noise and improve specificity in immunoassays. It is also used to reconstitute proteins, store antibodies, and prepare samples for downstream analysis. The buffer’s stability and compatibility with a wide range of biomolecules make it a staple in cell biology and protein purification protocols. Variants such as TBS with calcium and magnesium (TBS-Ca/Mg) are used in enzyme activity assays where divalent cations are required.

What are the advantages of using TBS over other buffers?

Compared to phosphate-buffered saline (PBS), TBS offers better buffering capacity at higher pH values and is less likely to precipitate with certain salts. It is also compatible with many downstream applications, including SDS-PAGE and NMR, provided that the Tris concentration is appropriate. However, Tris can interfere with some enzymatic reactions and is not recommended for use with certain metal chelators.

Related concepts

TBS is often compared to PBS and HEPES-buffered saline. It is commonly used alongside detergents, chelating agents, and blocking agents in immunoassays.