Polyxyethylenesorbitan(TWEEN 20)

Tween 20 is a polyoxyethylene sorbitol ester that belongs to the polysorbate family. It is a nonionic detergent having a molecular weight of 1,225 daltons, assuming 20 ethylene oxide units, 1 sorbitol, and 1 lauric acid as the primary fatty acid. The ethylene oxide subunits are responsible for the hydrophilic nature of the surfactant, while the hydrocarbon chains provide the hydrophobic environment. Sorbitol forms the backbone ring to which the ethylene oxide polymers are attached.

Application
TWEEN 20 has been used in staining buffer for in situ hybridization. It has also been used to prevent non-specific adsorption of proteins to coverslip during sample preparation for FRET (Förster resonance energy transfer) experiments.
TWEEN 20 is a nonionic detergent widely used in biochemical applications. It has been used as an emulsifying agent for the preparation of stable oil-in-water emulsions. TWEEN 20 has been used in pre-extraction of membranes to remove peripheral proteins (used at 2% for extraction of membrane-bound proteins).
TWEEN 20 has been used as a blocking agent for membrane based immunoassays at a typical concentration of 0.05%. TWEEN 20 can be used for lysing mammalian cells at a concentration of 0.005 to 0.5%.