Demierre Nicolas, Braschler Thomas, Linderholm Pontus, Seger Urban, van Lintel Harald, Renaud Philippe
Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland.
Lab Chip. 2007 Mar;7(3):355-65. doi: 10.1039/b612866a. Epub 2006 Dec 21.
Using the concept of insulator-based "electrodeless" dielectrophoresis, we present a novel geometry for shaping electric fields to achieve lateral deviation of particles in liquid flows. The field is generated by lateral planar metal electrodes and is guided along access channels to the active area in the main channel. The equipotential surfaces at the apertures of the access channels behave as vertical "liquid" electrodes injecting the current into the main channel. The field between a pair of adjacent liquid electrodes generates the lateral dielectrophoretic force necessary for particle manipulation. We use this force for high-speed deviation of particles. By adding a second pair of liquid electrodes, we focus a particle stream. The position of the focused stream can be swept across the channel by adjusting the ratio of the voltages applied to the two pairs. Based on conformal mapping, we provide an analytical model for estimating the potential at the liquid electrodes and the field distribution in the main channel. We show that the simulated particle trajectories agree with observations. Finally, we show that the model can be used to optimize the device geometry in different applications.
利用基于绝缘体的“无电极”介电泳概念，我们提出了一种用于塑造电场的新型几何结构，以实现液体流中粒子的横向偏移。该电场由横向平面金属电极产生，并沿着接入通道引导至主通道中的有源区域。接入通道孔处的等势面表现为垂直的“液体”电极，将电流注入主通道。一对相邻液体电极之间的电场产生了粒子操纵所需的横向介电泳力。我们利用该力实现粒子的高速偏移。通过添加第二对液体电极，我们可以聚焦粒子流。通过调整施加到两对电极上的电压之比，可以使聚焦流的位置在通道中扫过。基于保角映射，我们提供了一个分析模型，用于估计液体电极处的电势和主通道中的场分布。我们表明，模拟的粒子轨迹与观测结果相符。最后，我们表明该模型可用于优化不同应用中的器件几何结构。
