Pariset Eloise, Pudda Catherine, Boizot François, Verplanck Nicolas, Berthier Jean, Thuaire Aurélie, Agache Vincent
Univ. Grenoble Alpes, CEA, LETI, DTBS, 17 rue des Martyrs, F-38000, Grenoble, France.
Small. 2017 Oct;13(37). doi: 10.1002/smll.201701901. Epub 2017 Aug 7.
Deterministic lateral displacement (DLD) devices enable to separate nanometer to micrometer-sized particles around a cutoff diameter, during their transport through a microfluidic channel with slanted rows of pillars. In order to design appropriate DLD geometries for specific separation sizes, robust models are required to anticipate the value of the cutoff diameter. So far, the proposed models result in a single cutoff diameter for a given DLD geometry. This paper shows that the cutoff diameter actually varies along the DLD channel, especially in narrow pillar arrays. Experimental and numerical results reveal that the variation of the cutoff diameter is induced by boundary effects at the channel side walls, called the wall effect. The wall effect generates unexpected particle trajectories that may compromise the separation efficiency. In order to anticipate the wall effect when designing DLD devices, a predictive model is proposed in this work and has been validated experimentally. In addition to the usual geometrical parameters, a new parameter, the number of pillars in the channel cross dimension, is considered in this model to investigate its influence on the particle trajectories.
确定性侧向位移（DLD）装置能够在纳米到微米级尺寸的颗粒通过带有倾斜排柱的微流体通道传输过程中，围绕截止直径对其进行分离。为了针对特定分离尺寸设计合适的DLD几何结构，需要可靠的模型来预测截止直径的值。到目前为止，所提出的模型对于给定的DLD几何结构会得出单一的截止直径。本文表明，截止直径实际上沿DLD通道变化，特别是在窄柱阵列中。实验和数值结果表明，截止直径的变化是由通道侧壁处的边界效应（称为壁效应）引起的。壁效应会产生意想不到的颗粒轨迹，这可能会损害分离效率。为了在设计DLD装置时预测壁效应，本文提出了一个预测模型并通过实验进行了验证。除了通常的几何参数外，该模型还考虑了一个新参数，即通道横向尺寸中的柱数，以研究其对颗粒轨迹的影响。
