Mahaworasilpa T L, Coster H G, George E P
UNESCO Centre for Membrane Science and Technology, Department of Biophysics, University of New South Wales, Australia.
Biochim Biophys Acta. 1994 Jul 13;1193(1):118-26. doi: 10.1016/0005-2736(94)90340-9.
Measurements are presented of dielectrophoretic forces for SP2 (mouse) and K562 (human) cells in external alternating electric fields over a frequency range of 10 kHz to 2 MHz. Using a spherical shell model of the cell, the dielectrophoretic force is derived from the interaction between the induced electric dipole moment in the cell and the external electric field. The frequency dependence of the force has its origin in the dispersion with frequency of the impedances of the cell membrane, the cytoplasm and the external medium (a Maxwell-Wagner dispersion). The predicted tri-phasic form of the variation of the dielectrophoretic force is in good agreement with the experimental results presented. Using the theoretical model, the experimental measurements also provided an estimation of 0.18 +/- 0.03 S m-1 and 0.12 +/- 0.04 S m-1 for the conductivities of the cytoplasm of cells of SP2 and K562, respectively, and 6.0 +/- 2.0 mF m-2 and 2.0 +/- 1.0 mF m-2 for the capacitances of the plasma membrane of these cells.
给出了在10 kHz至2 MHz频率范围内，SP2（小鼠）和K562（人类）细胞在外部交变电场中的介电泳力测量结果。使用细胞的球壳模型，介电泳力由细胞中感应电偶极矩与外部电场之间的相互作用推导得出。该力的频率依赖性源于细胞膜、细胞质和外部介质阻抗随频率的色散（麦克斯韦-瓦格纳色散）。介电泳力变化的预测三相形式与所呈现的实验结果高度吻合。利用该理论模型，实验测量还分别给出了SP2和K562细胞细胞质电导率的估计值为0.18±0.03 S m-1和0.12±0.04 S m-1，以及这些细胞质膜电容的估计值为6.0±2.0 mF m-2和2.0±1.0 mF m-2。
