Driven transport of fluid vesicles through narrow pores

摘要

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 field 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 A0, and the pore size rp as f*/kBT~ ( kappa /kBT)1+ beta A-3/2+ eta 0r-2 eta p. 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 ~=0.2 and eta ~=2.4.