TBST

In molecular biology, TBST (or TTBS) is a 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. Tris is a pH buffer that maintains a pH that usually lies around pH=8. Buffered Saline is a salt that provides an isotone solution. Tween is a soap that removes fat droplets from the blot or well.
Contents of TBS-Tween.
The following is a sample recipe for TBST:
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.
References.
https://www.gbiosciences.com/Buffers-Reagents-Chemicals/Electrophoresis-Related-Buffers-Chemicals/TBST-10X