Phosphate Buffered Saline with Tween-20 (PBST) is a specialized variant of PBS, supplemented with Tween-20, a non-ionic surfactant. Tween-20 minimizes the non-specific binding and background noise, resulting in enhanced signal to noise ratio. PBST is often used in immunoassays such as ELISA and Western Blotting, where it serves as a washing and blocking buffer. With a stable buffering pH range between 7.0 and 7.4, PBST maintains ionic strength and protein solubility for biological assays.