Department of Chemistry and Biochemistry and Center for Solid State Electronics Research, Arizona State University, Tempe, AZ 85287, USA.
Electrophoresis. 2010 Nov;31(22):3634-41. doi: 10.1002/elps.201000438. Epub 2010 Oct 22.
Here we present a scheme to separate particles according to their characteristic physical properties, including size, charge, polarizability, deformability, surface charge mobility, dielectric features, and local capacitance. Separation is accomplished using a microdevice based on direct current insulator gradient dielectrophoresis that can isolate and concentrate multiple analytes simultaneously at different positions. The device is dependent upon dielectrophoretic and electrokinetic forces incorporating a global longitudinal direct current field as well as using shaped insulating features within the channel to induce local gradients. This design allows for the production of strong local field gradients along a global field causing particles to enter, initially transported through the channel by electrophoresis and electroosmosis (electrokinetics), and to be isolated via repulsive dielectrophoretic forces that are proportional to an exponent of the field gradient. Sulfate-capped polystyrene nano and microparticles (20, 200 nm, and 1 μm) were used as probes to demonstrate the influence of channel geometry and applied longitudinal field on separation behavior. These results are consistent with models using similar channel geometry and indicate that specific particulate species can be isolated within a distinct portion of the device, whereas concentrating particles by factors from 10(3) to 10(6).
在这里，我们提出了一种根据粒子的物理特性（包括大小、电荷、极化率、变形性、表面电荷迁移率、介电特性和局部电容）进行分离的方案。该分离方法基于基于直流梯度介电泳的微器件实现，可以同时在不同位置对多种分析物进行分离和浓缩。该器件依赖于介电泳和电动驱动力，结合全局纵向直流场，并在通道内使用成形的绝缘特征来诱导局部梯度。这种设计允许在全局场中产生强的局部场梯度，使粒子进入通道，最初通过电泳和电渗流（电动学）输送，并通过与场梯度的指数成正比的排斥介电泳力进行分离。用硫酸盐封端的聚苯乙烯纳米和微米颗粒（20、200nm 和 1μm）作为探针，演示了通道几何形状和施加的纵向场对分离行为的影响。这些结果与使用类似通道几何形状的模型一致，表明可以在器件的特定部分内分离特定的颗粒物质，同时将颗粒浓缩 10(3) 到 10(6) 倍。
