Effect of particles with repulsive interactions enclosed in both rigid spherical shells and flexible fluid vesicles studied by Monte Carlo simulation.

Experimental observations indicate that the repulsion of particles is a factor that induces the transformation of vesicles containing multiple particles. Metropolis Monte Carlo simulations are performed with two models in which repulsive particles are enclosed inside a vesicle. The distribution of the particles and the effective bending coefficient and surface tension of the membrane are analyzed. The shape and internal structure of the vesicle containing the particles are investigated as the vesicle volume is decreased. It is revealed that the repulsive interaction between particles produces a layered structure and stiffens the membrane. When particles repulsively interact over a long range, the membrane takes on a dumbbell form.