Tween 20

:Tween 20

(also known by various commercial brand names such as Kolliphor PS 20, Scattics, Alkest TW 20, and Kotilen-20) is a polysorbate-type nonionic surfactant. It is formed by the ethoxylation of sorbitan monolaurate. Let’s break down its properties and applications

:Properties

Chemical Formula: C₅₈H₁₁₄O₂₆

Molar Mass: 1226 g/mol

Appearance: Clear, yellow to yellow-green viscous liquid

Density: Approximately 1.1 g/mL

Boiling Point: >100 °C (212 °F; 373 K)

Surface Tension (CMC): 8.04×10⁻⁵ M at 21 °C

HLB (Hydrophilic-Lipophilic Balance): 16.71

Applications

Biotechnical Applications

Washing Agent in Immunoassays: Tween 20 is commonly used in techniques like Western blots and ELISAs. It helps prevent non-specific antibody binding. Typically, it is dissolved in Tris-buffered saline or phosphate buffered saline at dilutions of 0.05% to 0.5% v/v. These buffers are used for washes between immunoreactions to remove unbound immunologicals and reduce nonspecific background

Saturating Binding Sites on Surfaces: It coats polystyrene microplates (often combined with proteins like BSA) to stabilize binding sites

Stabilizing Proteins: In lysing mammalian cells, Tween 20 is used at a concentration of 0.05% to 0.5% v/v, often combined with other detergents, salts, and additives

Pharmaceutical Applications

Emulsions and Suspensions: Tween 20 acts as an excipient to stabilize emulsions and suspensions

Solubilizing Membrane Proteins: It is used during the isolation of membrane-protein complexes due to its low UV absorbance, making subsequent protein detection by UV light absorption feasible