In molecular biology, TBST (or TTBS) is mixture of tris-buffered saline (TBS) and Polysorbate 20 (also known as Tween 20). It is a buffer used for washing nitrocellulose membrane in western blotting and microtiter plate wells in ELISA assays.
The following is a sample recipe for TBST:50 mM Tris
150 mM NaCl
0.1% Tween 20
Adjust pH with HCl to pH 7.4 - 7.6
The simplest way to prepare a TBS-Tween solution is to use TBS-T tablets. They are formulated to give a ready to use TBST solution upon dissolution in 500 ml of deionized water.