Universality in the Dynamics of Vesicle Translocation through a Hole.

We analyze the translocation process of a spherical vesicle, made of a membrane and incompressible fluid, through a hole smaller than the vesicle size, driven by pressure difference Δ P . We show that such a vesicle shows certain universal characteristics, which are independent of the details of the membrane elasticity: (i) there is a critical pressure Δ P c below which no translocation occurs; (ii) Δ P c decreases to zero as the vesicle radius R 0 approaches the hole radius a , satisfying the scaling relation Δ P c ∼ ( R 0 - a ) 3/2 ; and (iii) the translocation time τ diverges as Δ P decreases to Δ P c , satisfying the scaling relation τ ∼ (Δ P - Δ P c ) -1/2 .