Electrokinetically driven concentration of particles and cells by dielectrophoresis with DC-offset AC electric field
Electrokinetically driven concentration of particles and cells by dielectrophoresis with DC-offset AC electric field
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DOI：
10.1007/s10404-011-0919-x
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发表时间：
2012-03-01
影响因子：
2.8
通讯作者：
Lam, Yee Cheong
中科院分区：
文献类型：
--
作者：
Lewpiriyawong, Nuttawut;Yang, Chun;Lam, Yee Cheong
基于绝缘体的介电电泳（iDEP）已成功地用于生物样品的芯片上操作。尽管其有效性，iDEP通常需要高DC电压来实现足够的电场;这主要是由于线性电动力学（电渗（EO）和电泳（EP））与非线性电动力学（介电泳（DEP））之间的耦合现象。本文提出了一种利用直流偏置交流电场的微流控技术，通过排斥性iDEP对颗粒和细胞进行电动浓缩。该技术引入用于产生iDEP的AC电场，其与电渗（EO）和电泳（EP）解耦。在PDMS锥形收缩通道中产生排斥性iDEP，该通道诱导非均匀电场。引入AC电场分量的益处是三方面的：（i）其有助于作用于颗粒上的DEP力，（ii）其抑制EO流动，以及（iii）其不引起任何EP运动。结果，可以显著减少主要用于基于EO和EP传输颗粒的所需DC场分量。数值模拟支持的实验结果表明，总的DC偏移AC电场强度所需的浓度为15 μ m的颗粒显着减少高达85.9%，相比，使用单一的DC电场。参数实验研究表明，较高的缓冲液浓度、较大的颗粒尺寸和较高的交直流电场比有利于颗粒的富集。此外，还证明了所提出的技术可用于酵母细胞的浓缩。
Insulator-based dielectrophoresis (iDEP) has been successfully used for on-chip manipulations of biological samples. Despite its effectiveness, iDEP typically requires high DC voltages to achieve sufficient electric field; this is mainly due to the coupled phenomena among linear electrokinetics: electroosmosis (EO) and electrophoresis (EP) and nonlinear electrokinetics: dielectrophoresis (DEP). This paper presents a microfluidic technique using DC-offset AC electric field for electrokinetic concentration of particles and cells by repulsive iDEP. This technique introduces AC electric field for producing iDEP which is decoupled from electroosmosis (EO) and electrophoresis (EP). The repulsive iDEP is generated in a PDMS tapered contraction channel that induces non-uniform electric field. The benefits of introducing AC electric field component are threefold: (i) it contributes to DEP force acting on particles, (ii) it suppresses EO flow and (iii) it does not cause any EP motion. As a result, the required DC field component that is mainly used to transport particles on the basis of EO and EP can be significantly reduced. Experimental results supported by numerical simulations showed that the total DC-offset AC electric field strength required to concentrate 15-mu m particles is significantly reduced up to 85.9% as compared to using sole DC electric field. Parametric experimental studies showed that the higher buffer concentration, larger particle size and higher ratio of AC-to-DC electric field are favorable for particle concentration. In addition, the proposed technique was demonstrated for concentration of yeast cells.