Spontaneous Localization of Particles in Giant Vesicles Owing to Depletion Force

When two kinds of particles with different sizes were encapsulated into identical giant vesicles, the small particles were localized near the inner membrane. The vesicles contained several hundreds of large particles and their volume fraction exceeded that of the small particles. Under the characteristic condition, where not only small but large particles are also considered as statistical ensembles contributing to the depletion force, the depletion force received by a small particle was estimated to be almost the same as that received by a large particle. In addition to this effect, small particles can be more accessible to the inner membrane.