Velev Orlin D, Bhatt Ketan H
Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Soft Matter. 2006 Aug 16;2(9):738-750. doi: 10.1039/b605052b.
We overview the ways in which electric fields can be used for on-chip manipulation and assembly of colloidal particles. Particles suspended in water readily respond to alternating (AC) or direct current (DC) electric fields. Charged particles in DC fields are moved towards oppositely charged electrodes by electrophoresis. Dielectrophoresis, particle mobility in AC fields, allows precise manipulation of particles through a range of parameters including field strength and frequency and electrode geometry. Simultaneously, DC or AC electrokinetics may drive liquid flows inside the experimental cells, which also leads to transport and redistribution of the suspended particles. Examples of dielectrophoretic manipulation and assembly of nanoparticles and microparticles by planar on-chip electrodes are presented. The structures assembled include conductive microwires from metallic nanoparticles and switchable two-dimensional crystals from polymer microspheres. We also discuss how dielectrophoresis and AC electrokinetics can be used in droplet-based microfluidic chips, biosensors, and devices for collection of particles from diluted suspensions.
我们概述了电场可用于片上操纵和组装胶体颗粒的方式。悬浮在水中的颗粒很容易对交变（AC）或直流（DC）电场作出响应。直流电场中的带电粒子通过电泳向带相反电荷的电极移动。介电泳，即颗粒在交流电场中的迁移率，允许通过一系列参数（包括场强、频率和电极几何形状）对颗粒进行精确操纵。同时，直流或交流电动学可能会驱动实验池内的液体流动，这也会导致悬浮颗粒的运输和重新分布。展示了通过平面片上电极进行介电泳操纵和组装纳米颗粒和微粒的示例。组装的结构包括由金属纳米颗粒制成的导电微线和由聚合物微球制成的可切换二维晶体。我们还讨论了介电泳和交流电动学如何用于基于液滴的微流控芯片、生物传感器以及从稀释悬浮液中收集颗粒的装置。
