Ability of sodium dodecyl sulfate to transiently stabilize a phospholipid molecular layer

• Water in oil droplets and the surface pressure – area isotherm were examined.
• A lipid molecular layer was stabilized with a surfactant at ~ 2 mM.
• The concentration range was close to the critical micelle concentration.
• The interaction between lipid and surfactant was evaluated spectrophotometrically.

The interaction between sodium dodecyl sulfate (SDS) and a phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) molecular layer was investigated experimentally to understand the mixing effect of SDS on biomembranes. Both the SDS concentration-dependencies of the contact angle between a pair of water droplets in oil and the surface pressure of a DOPC phospholipid monolayer changed at 1 ~ 2 mM SDS, which was lower than the critical micelle concentration. Attenuated total reflection Fourier transform infrared spectroscopy was used to evaluate the interaction between DOPC and SDS molecules.