Eur. Phys. J. E (2007) 22: 303-309
https://doi.org/10.1140/epje/e2007-00038-5

Regular Articles

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

^* e-mail: aerbe@arcor.de
^** e-mail: sigel@mpikg.mpg.de

Received: 18 August 2006
Published online: 13 April 2007

Abstract

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.