Electrophoresis of a Membrane-Coated Cylindrical Particle Positioned Eccentrically along the Axis of a Narrow Cylindrical Pore

Although theoretical analyses on electrophoresis are ample in the literature, most of them focused on the one- or two-dimensional problems for a simpler treatment; available results for the three-dimensional case, which may be closer to reality, are extremely limited. The electrophoresis of a soft, finite cylindrical particle positioned eccentrically along the axis of a narrow cylindrical pore is modeled in this study. The type of particle considered is capable of mimicking a wide class of nonrigid entities such as biocolloids and particles covered by an artificial polymer layer in practice. The electrophoretic behaviors of the particle under various conditions are simulated. We show that if the membrane layer of a particle is charged, then its electrophoretic behavior depends largely on its aspect ratio, eccentricity, and relative size, the thickness of double layer, and the thickness of the membrane layer, which might not be the case if that layer is uncharged. In addition, the electrophoretic mobility of a particle in the former may not increase with increasing thickness of the membrane layer, which has not been reported previously. The results gathered provide the theoretical basis for both the design of an electrophoresis apparatus and the interpretation of experimental data.