Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI, 53211, USA.
Center for Systems Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.
Biomed Microdevices. 2021 Jun 29;23(3):33. doi: 10.1007/s10544-021-00570-3.
Dielectrophoresis, an electrokinetic technique, can be used for contactless manipulation of micro- and nano-size particles suspended in a fluid. We present a 3-D microfluidic DEP device with an orthogonal electrode configuration that uses negative dielectrophoresis to trap spherical polystyrene micro-particles. Traps with three different basic geometric shapes, i.e. triangular, square, and circular, and a fixed trap area of around 900 μm were investigated to determine the effect of trap shape on dynamics and strength of particle trapping. Effects of trap geometry were quantitatively investigated by means of trap stiffness, with applied electric potentials from 6 V to 10 V at 1 MHz. Analyzing the trap stiffness with a trapped 4.42 μm spherical particle showed that the triangular trap is the strongest, while the square shape trap is the weakest. The trap stiffness grew more than eight times in triangular traps and six times in both square and circular traps when the potential of the applied electric field was increased from 6 V to 10 V at 1 MHz. With the maximum applied potential, i.e. 10 V at 1 MHz, the stiffness of the triangular trap was 60% and 26% stronger than the square and circular trap, respectively. A finite element model of the microfluidic DEP device was developed to numerically compute the DEP force for these trap shapes. The findings from the numerical computation demonstrate good agreement with the experimental analysis. The analysis of three different trap shapes provides important insights to predict trapping location, strength of the trapping zone, and optimized geometry for high throughput particle trapping.
介电泳是一种电动技术，可用于非接触式操纵悬浮在流体中的微纳米尺寸的颗粒。我们提出了一种具有正交电极配置的三维微流介电泳（DEP）装置，该装置使用负介电泳来捕获球形聚苯乙烯微颗粒。我们研究了三种不同基本几何形状的阱，即三角形、正方形和圆形，以及固定的约 900μm² 的阱面积，以确定阱形状对颗粒捕获动力学和强度的影响。通过使用从 6V 到 10V 的施加电势在 1MHz 下测量阱刚度，定量研究了阱几何形状的影响。用捕获的 4.42μm 球形颗粒分析阱刚度表明，三角形阱的强度最大，而正方形阱的强度最小。当在 1MHz 下将施加电场的电势从 6V 增加到 10V 时，三角形阱的刚度增加了超过八倍，而正方形和圆形阱的刚度增加了六倍。在最大施加电势下，即 1MHz 下的 10V，三角形阱的刚度比正方形和圆形阱分别强 60%和 26%。开发了微流介电泳装置的有限元模型，以数值计算这些阱形状的介电泳力。数值计算的结果与实验分析吻合较好。对三种不同阱形状的分析为预测捕获位置、捕获区域的强度以及用于高通量颗粒捕获的优化几何形状提供了重要的见解。
