DRIVEN TRANSPORT OF FLUID VESICLES THROUGH NARROW PORES

The driven transport of fluid vesicles through narrow, cylindrical pores in a linear external potential is studied using Monte Carlo simulations, scaling arguments, and mean-field theory. The. mobility of the vesicles increases sharply when the strength f of the driving held exceeds a threshold value f*. For f > f*, the mobility saturates at a value that is essentially independent of the strength of the driving field. The threshold field strength f* is found to scale with the membrane bending rigidity kappa, the vesicle area A(0), and the pore size Gamma(p) as f*/k(B)T similar to (kappa/k(B)T)(1+beta) A(0)(-3/2+eta)Gamma(p)(-2 eta). An analysis of the zero-temperature limit yields the exponents beta = 0 and eta = 1.55, while the Monte Carlo simulations of low-bending-rigidity vesicles are well described by the (effective) exponents beta similar or equal to 0.2 and eta similar or equal to 2.4.