Shape deformation of vesicle coupled with phase separation

In the presence of the osmotic pressure difference between the inside and outside of the vesicles, spherical vesicles deform into various shapes, such as prolates, discocytes, and starfish, depending on excess areas and area differences. When we couple such shape deformation with phase separation, the lateral heterogeneity arising from phase separation in membranes causes new shape-deformation branches. In domain coarsening stage, prolate, discocyte, and starfish vesicles show a shape convergence to discocytes. In late stage, domains start to bud toward inside or outside of the vesicle depending on the excess area. We discuss the deformation branches in terms of the membrane elasticity model for multi-component vesicles.