Dynamic microparticle manipulation with an electroosmotic flow gradient in low-frequency alternating current dielectrophoresis
Dynamic microparticle manipulation with an electroosmotic flow gradient in low-frequency alternating current dielectrophoresis
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DOI：
10.1002/elps.201300385
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发表时间：
2014-02-01
期刊：
影响因子：
2.9
通讯作者：
Lapizco-Encinas, Blanca H.
中科院分区：
文献类型：
--
作者：
Gencoglu, Aytug;Olney, David;Lapizco-Encinas, Blanca H.
在这项研究中，探索了基于低频交流绝缘子的DEP(IDEP)用于分离聚苯乙烯微粒和酵母细胞的潜力。在由具有钻石形绝缘柱的微通道组成的IDEP装置中，通过使用不对称的20赫兹交流电信号来产生EOF梯度。分析了两种类型的样品，第一种样品含有三种不同直径的聚苯乙烯颗粒(0.5、1.0和2.0m)，第二种样品含有两种类型的聚苯乙烯颗粒(1.0和2m)和酵母细胞(6.3m)。这种特殊的方案使用锥形交流信号，允许所有颗粒被捕获并集中在绝缘柱阵列上，当信号变得不对称(更正)时，颗粒被选择性地释放。每个样品中最小的颗粒首先被释放，因为它们需要更大的介电泳力才能保持捕获。当施加的信号变得周期性时，每个样本中最大的颗粒最后被释放。每个样品都得到了类似于色谱图的介电泳图，通过显示释放的颗粒的峰，证明了颗粒的成功分离。这些分离是在较低的外加电位下实现的，而不是以前的研究中报道的仅使用直流电压的分离。此外，考虑到实验中使用的低频、不对称的交流信号，使用COMSOL多物理进行了数学建模，以估计作用在粒子上的介电和EOF力的大小。结果表明，低频AC-IDEP系统在处理和分离微粒和生物细胞的复杂混合物方面具有潜力。
In this study, the potential of low-frequency AC insulator-based DEP (iDEP) was explored for the separation of polystyrene microparticles and yeast cells. An EOF gradient was generated by employing an asymmetrical, 20 Hz AC electrical signal in an iDEP device consisting of a microchannel with diamond-shaped insulating posts. Two types of samples were analyzed, the first sample contained three types of polystyrene particles with different diameters (0.5, 1.0, and 2.0 m) and the second sample contained two types of polystyrene particles (1.0 and 2 m) and yeast cells (6.3 m). This particular scheme uses a tapered AC signal that allows for all particles to be trapped and concentrated at the insulating post array, as the signal becomes asymmetrical (more positive), particles are selectively released. The smallest particles in each sample were released first, since they require greater dielectrophoretic forces to remain trapped. The largest particles in each sample were released last, when the applied signal became cyclical. A dielectropherogram, which is analogous to a chromatogram, was obtained for each sample, demonstrating successful separation of the particles by showing peaks of the released particles. These separations were achieved at lower applied potentials than those reported in previous studies that used solely direct current electrical voltages. Additionally, mathematical modeling with COMSOL Multiphysics was carried out to estimate the magnitude of the dielectrophoretic and EOF forces acting on the particles considering the low-frequency, asymmetrical AC signal used in the experiments. The results demonstrated the potential of low-frequency AC-iDEP systems for handling and separating complex mixtures of microparticles and biological cells.