Elastocytosis

Endocytosis and exocytosis are key mechanisms in cellular systems by which a cell deforms its plasma membrane to move substances in or out of the cell. Whereas these cellular processes typically rely on active mechanisms, we study here the problem of achieving encapsulation by a purely physical process. We consider an ideal system in which a rigid particle is put in contact with a spherical deformable body. Depending on the interaction energy between both objects and the mechanical response of the body, partial or total encapsulation may reduce the total energy of the system. In this case, the system would evolve naturally so that the particle will be partially or completely engulfed by the body, a process that we refer to as partial or complete elastocytosis. We consider three systems of increasing complexity and we show that elastocytosis is a generic mechanism that can always be achieved in some parameter regimes.