Migration and deformation of polyelectrolyte vesicle through a pore in electric field

Abstract

With the finite element method adopted to solve the coupling of the fluid flow, the deformation of viscoelastic membrane and the distribution of electric field, the dynamic behavior of the polyelectrolyte vesicle is investigated through a pore in the electric field. The velocity of the vesicle is reduced significantly when it approaches the pore, with the vesicle showing a bullet-like shape. Then, the velocity reaches its minimum when the vesicle approaches the center of the pore. At this time, it shows a long-strip shape with the diameter of the vesicle being no greater than the pore diameter, otherwise, it shows a slipper-like shape. After the pore is past through, a sharp increase in vesicle velocity is observed. In addition, as the lengths of pores or the diameters of vesicles increase, the minimum velocity of the vesicles along the horizontal direction declines gradually while the translocation time is extended significantly. Our results further demonstrate that the surface potential of membrane increases slowly when the vesicles approach and escape from the pore but rises sharply when they are passing through the pore. The competition of membrane surface potential, fluid resistance, and pore restriction cause the deformation of the vesicles to peak over the course of migration. Our work is believed to lay a theoretical foundation for the migration, rotation, and deformation of vesicles, thus providing valuable information for such applications as drug carrier and the experimentation on biofilm simulation.