Abstract
Since phospholipids are the basic molecules of biomembranes, giant uni-lamellar vesicles (GUVs) of phospholipids with 1-10μm in diameter have been extensively studied to understand the actual behavior of biomembranes as a model cell. Phospholipids, however, normally grow as multi-lamellar vesicles which are not suitable for constructing the model cells. It has been recently shown that the addition of sugar or salt promotes the formation of GUVs when they are mixed with phospholipid films before hydration. The mechanism of the GUV formation induced by the additives was, however, not clarified. In this study, neutron reflectometry, small-angle X-ray scattering, and phase-contrast microscopy experiments were performed, and it is confirmed that the osmotic pressure induced by the additives in a lipid/additive mixture film promotes the formation of GUVs.
