Kua Chin Hock, Lam Yee Cheong, Rodriguez Isabel, Yang Chun, Youcef-Toumi Kamal
Singapore-MIT Alliance, and School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798.
Anal Chem. 2008 Jul 15;80(14):5454-61. doi: 10.1021/ac800947e. Epub 2008 Jun 18.
Moving dielectrophoresis has been recently developed by the authors as an alternative method to achieve simultaneous cell fractionation and transportation. With an array of independently excitable microelectrodes, this method generates a moving electric field to sequentially fractionate and transport cells across a microchannel. Due to the peculiarity of this method, the motion of the cells is unsteady and there are interesting and distinct differences between cells experiencing positive or negative dielectrophoresis. For a proper understanding and design of a microdevice utilizing this methodology, this study presents a model for the equation of motion for a polarized cell and its unsteady motion under moving dielectrophoresis. The model considers the basic module to generate a moving electric field, where there is a finite-width top electrode and an infinite-width bottom electrode, in a parallel-plate configuration. The forces considered include dielectrophoretic force, fluid drag, buoyancy, and gravitational force. These forces are modeled as equivalent point forces acting at the center of mass of the cell. A parallel-plate wall correction factor is employed to account for the effect of the large cell size to microchannel height ratio. Various parameters are examined including the initial position of the cell relative to the electrodes, cell's Clausius-Mossotti factor, cell size, applied voltage, electrode width, interelectrode gap, microchannel height, number of energized electrodes, and types of electrode configurations. Reasonable agreements were obtained between simulated and experimental results. As the solution of the unsteady motion is rather tedious, a MATLAB algorithm, with all the associated files, for the prediction of the cell trajectory, is available on request.
作者最近开发了一种移动介电泳方法，作为实现细胞同时分离和运输的替代方法。利用一系列可独立激发的微电极，该方法产生一个移动电场，以在微通道中依次对细胞进行分离和运输。由于该方法的特殊性，细胞的运动是不稳定的，并且经历正介电泳或负介电泳的细胞之间存在有趣且明显的差异。为了正确理解和设计利用这种方法的微器件，本研究提出了一个极化细胞运动方程及其在移动介电泳下的不稳定运动模型。该模型考虑了产生移动电场的基本模块，其中在平行板配置中有一个有限宽度的顶部电极和一个无限宽度的底部电极。所考虑的力包括介电泳力、流体阻力、浮力和重力。这些力被建模为作用在细胞质心的等效点力。采用平行板壁校正因子来考虑大细胞尺寸与微通道高度比的影响。研究了各种参数，包括细胞相对于电极的初始位置、细胞的克劳修斯 - 莫索蒂因子、细胞大小、施加电压、电极宽度、电极间隙、微通道高度、通电电极数量以及电极配置类型。模拟结果与实验结果取得了合理的一致性。由于不稳定运动的解相当繁琐，可根据要求提供一个用于预测细胞轨迹的MATLAB算法及所有相关文件。
