Dielectrophoresis (DEP), the migration of particles due to polarization effects under the influence of a nonuniform electric field, was employed for characterizing the behavior and achieving the separation of larger (diameter >5 μm) microparticles by exploiting differences in electrical charge. Usually, electrophoresis (EP) is the method of choice for separating particles based on differences in electrical charge; however, larger particles, which have low electrophoretic mobilities, cannot be easily separated with EP-based techniques. This study presents an alternative for the characterization, assessment, and separation of larger microparticles, where charge differences are exploited with DEP instead of EP. Polystyrene microparticles with sizes varying from 5 to 10 μm were characterized employing microdevices for insulator-based dielectrophoresis (iDEP). Particles within an iDEP microchannel were exposed simultaneously to DEP, EP, and electroosmotic (EO) forces. The electrokinetic behavior of four distinct types of microparticles was carefully characterized by means of velocimetry and dielectrophoretic capture assessments. As a final step, a dielectropherogram separation of two distinct types of 10 μm particles was devised by first characterizing the particles and then performing the separation. The two types of 10 μm particles were eluted from the iDEP device as two separate peaks of enriched particles in less than 80 s. It was demonstrated that particles with the same size, shape, surface functionalization, and made from the same bulk material can be separated with iDEP by exploiting slight differences in the magnitude of particle charge. The results from this study open the possibility for iDEP to be used as a technique for the assessment and separation of biological cells that have very similar characteristics (shape, size, similar make-up), but slight variance in surface electrical charge.

介电电泳（DEP）是在不均匀电场的影响下由于极化效应而引起的粒子迁移，被用于表征行为并通过利用电荷差异实现较大（直径> 5μm）微粒的分离。通常，电泳（EP）是根据电荷差异分离颗粒的一种选择方法。然而，具有低电泳迁移率的较大颗粒不能通过基于EP的技术轻易分离。这项研究为表征，评估和分离较大的微粒提供了另一种方法，其中用DEP代替EP利用电荷差异。使用基于绝缘子的介电电泳（iDEP）的微器件对尺寸为5至10μm的聚苯乙烯微粒进行了表征。iDEP微通道中的颗粒同时暴露于DEP，EP和电渗（EO）力。通过测速法和介电泳捕获评估，仔细表征了四种不同类型的微粒的电动行为。最后一步，通过首先表征颗粒然后进行分离，设计出两种截然不同的10μm颗粒的双电图分离。两种类型的10μm颗粒在不到80 s的时间内从iDEP装置中洗脱出两个单独的富集峰。事实证明，通过利用颗粒电荷大小的细微差别，可以用iDEP分离具有相同尺寸，形状，表面功能化和由相同块状材料制成的颗粒。这项研究的结果为将iDEP用作评估和分离具有非常相似特征（形状，大小，相似组成）但表面电荷略有变化的生物细胞的可能性开辟了可能性。