Unbinding of lipid bilayers induced by osmotic pressure in relation to unilamellar vesicle formationN. L. Yamada1, M. Hishida2, H. Seto2, K. Tsumoto3 and T. Yoshimura3
1 Institute of Materials Structure Science, High Energy Accelerator Research Organization - Oho, Tsukuba, Ibaraki, 305-0801, Japan
2 Department of Physics, Kyoto University - Kitashirakawa-oiwake-cho, Sakyo, Kyoto, 606-8502, Japan
3 Department of Chemistry for Materials, Mie University - Kurimamachiya-cho, Tsu, Mie, 514-8507, Japan
received 12 March 2007; accepted in final form 13 September 2007; published November 2007
published online 10 October 2007
Small-angle X-ray scattering and phase-contrast microscopy experiments were performed to investigate the effect of osmotic pressure on vesicle formation in a dioleoyl-phosphatidylcholine (DOPC)/water/NaI system. The multi-lamellar structure of lipid bilayers is unstabilized when a lipid film with a sufficient amount of NaI is hydrated by pure water. It has been confirmed that this phenomenon is due to the effect of osmotic pressure induced by a hetero- geneous distribution of NaI molecules. This could be the origin of the unbinding of lipid bilayers to conform large uni-lamellar vesicles.
87.14.Cc - Lipids.
87.16.Dg - Membranes, bilayers, and vesicles.
61.10.Eq - X-ray scattering (including small-angle scattering).
© Europhysics Letters Association 2007