Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
Colloids Surf B Biointerfaces. 2011 Dec 1;88(2):559-67. doi: 10.1016/j.colsurfb.2011.07.033. Epub 2011 Jul 23.
The electrophoresis of a soft particle comprising a rigid core and a charged porous membrane layer in a narrow space is modeled. This simulates, for example, the capillary electrophoresis of biocolloids such as cells and microorganisms, and biosensor types of device. We show that, in addition to the boundary effect, the effects of double-layer polarization (DLP) and the electroosmotic retardation flow can be significant, yielding interesting electrophoretic behaviors. For example, if the friction coefficient of the membrane layer and/or the boundary is large, then the DLP effect can be offset by the electroosmotic retardation flow, making the particle mobility to decrease with increasing double layer thickness, which is qualitatively consistent with many experimental observations in the literature, but has not been explained clearly in previous analyses. In addition, depending upon the thickness of double layer, the friction of the membrane layer of a particle can either retard or accelerate its movement, an interesting result which has not been reported previously. This work is the first attempt to show solid evidence for the influence of a boundary on the effect of DLP and the electrophoretic behavior of soft particles. The model proposed is verified by the experimental data in the literature. The results of numerical simulation provide valuable information for the design of bio-analytical apparatus such as nanopore-based sensing applications and for the interpretation of relevant experimental data.
对刚性核心和带电多孔膜层组成的软粒子在狭窄空间中的电泳进行建模。这模拟了例如细胞和微生物等生物胶体的毛细管电泳，以及生物传感器类型的装置。我们表明，除了边界效应外，双电层极化（DLP）和电渗流的影响也可能很显著，从而产生有趣的电泳行为。例如，如果膜层和/或边界的摩擦系数较大，则电渗流可以抵消 DLP 效应，使粒子的迁移率随双层厚度的增加而减小，这与文献中的许多实验观察结果定性一致，但在以前的分析中没有得到明确解释。此外，根据双层的厚度，粒子的膜层的摩擦可以使粒子的运动减速或加速，这是一个以前没有报道过的有趣结果。这项工作首次尝试证明边界对 DLP 效应和软粒子电泳行为的影响。所提出的模型通过文献中的实验数据进行了验证。数值模拟的结果为基于纳米孔的传感应用等生物分析仪器的设计以及相关实验数据的解释提供了有价值的信息。
