Tilt angle of lipid acyl chains in unilamellar vesicles determined by ellipsometric light scattering
Max Planck Institute of Colloids and Interfaces, Wissenschaftspark Golm, Am Mühlenberg 1, 14476, Golm, Germany
Published online: 13 April 2007
Ellipsometric light scattering (ELS) at room temperature is applied to unilamellar vesicles (~50 nm radius) of 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in the gel phase and of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) in the liquid-crystaline phase. A high sensitivity of this technique to the local anisotropy is found. From the resulting local birefringence, a lower limit of (29 ±0.5)○ for the average tilt angle of the lipid chains of DPPC with respect to the membrane normal is estimated. This tilt angle value is slightly lower than literature values for the tilt angle in oriented lipid multi-bilayers on solid substrates.
PACS: 87.16.Dg Membranes, bilayers, and vesicles – / 42.68.Mj Scattering, polarization – / 42.81.Gs Birefringence, polarization – / 87.14.Cc Lipids –
© EDP Sciences/Società Italiana di Fisica/Springer-Verlag, 2007