Electrophoretic mobility of heterogeneous vesicles

Unlike rigid uniformly charged particles, vesicles bearing transmembrane inclusions undergo, under electrophoretic motion, a redistribution of their surface charges. We study how this internal response of the vesicle affects its electrophoretic mobility, which is shown to depend on the vesicle size, on the average inclusion concentration and on the field intensity. The surface reorganization of the inclusions may cause the mobility to change sign as the field is increased. From our analysis, free-flow fractionation methods can be envisaged.