Department of Mechanical Engineering, Clemson University, Clemson, South Carolina, USA.
Electrophoresis. 2024 Apr;45(7-8):712-719. doi: 10.1002/elps.202300188. Epub 2023 Oct 25.
Nonlinear electrophoresis offers advantageous prospects in microfluidic manipulation of particles over linear electrophoresis. Existing theories established for this phenomenon are entirely based on spherical particle models, some of which have been experimentally verified. However, there is no knowledge on if and how the particle shape may affect the nonlinear electrophoretic behavior. This work presents an experimental study of the nonlinear electrophoretic velocities of rigid peanut- and pear-shaped particles in a rectangular microchannel, which are compared with rigid spherical particles of similar diameter and surface charge in terms of the particle slenderness. We observe a decrease in the nonlinear electrophoretic mobility, whereas an increase in the nonlinear index of electric field when the particle slenderness increases from the peanut- to pear-shaped and spherical particles. The values of the nonlinear index for the nonspherical particles are, however, still within the theoretically predicted range for spherical particles. We also observe an enhanced nonlinear electrophoretic behavior in a lower concentration buffer solution regardless of the particle shape.
非线性电泳在微流控粒子操纵方面提供了优于线性电泳的有利前景。现有的针对这一现象的理论完全基于球形粒子模型，其中一些已经过实验验证。然而，关于粒子形状是否以及如何影响非线性电泳行为，目前还没有相关知识。本工作通过实验研究了在矩形微通道中刚性花生形和梨形粒子的非线性电泳速度，并与具有相似直径和表面电荷的刚性球形粒子进行了比较，比较的依据是粒子的细长比。我们观察到，当粒子的细长比从花生形变为梨形和球形时，非线性电泳迁移率会降低，而电场的非线性指数会增加。然而，对于非球形粒子，非线性指数的值仍在理论预测的球形粒子范围内。我们还观察到，无论粒子形状如何，在较低浓度的缓冲溶液中都会增强非线性电泳行为。
