Phase separation of giant vesicles composed of neutral saturated lipid, negatively charged
unsaturated lipid, and cholesterol, is observed at different calcium concentrations. Confocal
microscopy provides the information where the phase separation becomes distinct as the
calcium concentration is increased. The charged domains tend to bud toward the interior of
the vesicle. This budding is assumed to be due to an increase in the osmotic pressure, in
cooperation with the spontaneous curvature change in the outer leaflet of the bilayer caused …