Abstract
The organization of lateral domains, called lipid rafts, in plasma membranes is essential for physiological functions, such as signaling and trafficking. Membrane domains are considered to be a form of two-dimensional phase separation that develops due to the interaction between lipid molecules. To reveal the physicochemical properties of membrane domains, we have developed model membrane systems using multi-component giant vesicles. The vesicles which are composed of saturated and unsaturated lipids together with cholesterol show phase separation into domains. We clarified the shifts in phase structures within bilayer membranes with change in tension and temperature. The miscibility transition temperature between one-liquid and two-liquid states was shown to increase under tension (Soft Matter, 7, 9061-9068, 2011). We also found that membrane domains mediate the partitioning of nanoparticles in a size-dependent manner: small particles were localized in an ordered phase, whereas large particles preferred a fluidic disordered phase (J. Am. Chem. Soc., 134, 13990-13996, 2012).
