Zhao Yu, Brcka Jozef, Faguet Jacques, Zhang Guigen
F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, 522A Robotics and Manufacturing Building, 143 Graham Avenue, Lexington, KY, 40506-0108, USA.
Tokyo Electron Technology Center, America, LLC, US-Technology Development Center, Austin, TX, 78741, USA.
Biomed Microdevices. 2018 Sep 8;20(3):81. doi: 10.1007/s10544-018-0327-z.
Cell rotation can be achieved by utilizing rotating electric fields through which torques are generated due to phase difference between the dipole moment of cells and the external electric field. While reports of cell rotation under non-rotating electrical fields, such as dielectrophoresis (DEP), are abound, the underlying mechanism is not fully understood. Because of this, contradicting arguments remain regarding if a single cell can rotate under conventional DEP. What's more, the current prevailing DEP theory is not adequate for identifying the cause for such disagreements. In this work we applied our recently developed Volumetric Polarization and Integration (VPI) method to investigate the possible causes for cell rotation under conventional DEP. Three-dimensional (3D) computer models dealing with a cell in a DEP environment were developed to quantify the force and torque imparted on the cell by the external DEP field using COMSOL Multiphysics software. Modeling results suggest that eccentric inclusions with low conductivity inside the cell will generate torques (either in clockwise or counter-clockwise directions) sufficient to cause cell rotation under DEP. For validation of modeling predictions, experiments with rat adipose stem cells containing large lipid droplets were conducted. Good agreement between our modeling and experimental results suggests that the VPI method is powerful in elucidating the underlying mechanisms governing the complicated DEP phenomena.
通过利用旋转电场可以实现细胞旋转，由于细胞偶极矩与外部电场之间的相位差，会在旋转电场中产生扭矩。虽然在非旋转电场（如介电电泳，DEP）下细胞旋转的报道很多，但其潜在机制尚未完全理解。因此，关于单个细胞在传统DEP下是否能够旋转仍存在相互矛盾的观点。此外，当前流行的DEP理论不足以确定这种分歧的原因。在这项工作中，我们应用了我们最近开发的体积极化与积分（VPI）方法来研究传统DEP下细胞旋转的可能原因。使用COMSOL Multiphysics软件开发了处理DEP环境中细胞的三维（3D）计算机模型，以量化外部DEP场施加在细胞上的力和扭矩。建模结果表明，细胞内具有低电导率的偏心内含物将产生足以在DEP下导致细胞旋转的扭矩（顺时针或逆时针方向）。为了验证建模预测，对含有大脂滴的大鼠脂肪干细胞进行了实验。我们的建模与实验结果之间的良好一致性表明，VPI方法在阐明控制复杂DEP现象的潜在机制方面很强大。
