Depto. Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012, Sevilla, Spain; International Iberian Nanotechnology Laboratory (INL), Braga 4715-330, Portugal.
School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, United Kingdom.
J Chromatogr A. 2023 Sep 13;1706:464240. doi: 10.1016/j.chroma.2023.464240. Epub 2023 Jul 28.
Deterministic Lateral Displacement (DLD) exploits periodic arrays of pillars inside microfluidic channels for high-precision sorting of micro- and nano-particles. Previously we demonstrated how DLD separation can be significantly improved by the addition of AC electrokinetic forces, increasing the tunability of the technique and expanding the range of applications. At high frequencies of the electric field (>1 kHz) the behaviour of such systems is dominated by Dielectrophoresis (DEP), whereas at low frequencies the particle behaviour is much richer and more complex. In this article, we present a detailed numerical analysis of the mechanisms governing particle motion in a DLD micropillar array in the presence of a low-frequency AC electric field. We show how a combination of Electrophoresis (EP) and Concentration-Polarisation Electroosmosis (CPEO) driven wall-particle repulsion account for the observed experimental behaviour of particles, and demonstrate how this complete model can predict conditions that lead to electrically induced deviation of particles much smaller than the critical size of the DLD array.
确定性横向位移（DLD）利用微流道内周期性的柱子阵列，实现微纳米颗粒的高精度分选。我们之前曾展示过，通过引入交流电动场力，DLD 分离的效果可以得到显著提升，从而提高了该技术的可调性并扩展了其应用范围。在电场的高频（>1 kHz）下，这种系统的行为主要由介电泳（DEP）决定，而在低频下，颗粒的行为则更加丰富和复杂。在本文中，我们对存在低频交流电场时，控制 DLD 微柱阵列中颗粒运动的机制进行了详细的数值分析。我们展示了电泳（EP）和浓度极化电渗流（CPEO）驱动的壁-颗粒斥力的组合如何解释观察到的颗粒实验行为，并演示了这种完整的模型如何预测导致颗粒电诱导偏离的条件，其偏离程度远小于 DLD 阵列的临界尺寸。
