Miller R D, Jones T B
Department of Electrical Engineering, University of Rochester, New York 14627.
Biophys J. 1993 May;64(5):1588-95. doi: 10.1016/S0006-3495(93)81529-7.
The frequency-dependent orientation of human and llama erythrocytes suspended in isotonic solutions and subjected to linearly polarized electric fields is examined. Human erythrocytes may be represented as oblate spheroids (3.9:3.9:1.1 microns) with two distinguishable orientations, while the llama cells are approximated as ellipsoids with three distinct axes (4.0:2.0:1.1 microns). Under appropriate experimental conditions, both orientations of the human cells and all three orientations of the llama cells are observed. A theoretical cell model which accounts for the membrane as a thin confocal layer of ideal capacitance is used to predict the orientational spectra. The predicted spectra compare favorably in frequency range and orientational sequence with experimental data. Estimates for cell internal conductivity and permittivity are obtained by adjusting the values of these important parameters to achieve the closet fit of the theoretical curves to the data. By the use of this method, the internal conductivity of llama erythrocytes is estimated to be 0.26 S/m (+/- 20%), while the effective internal dielectric constant and conductivity of Euglena gracilis are estimated to be 120 (+/- 10%) and 0.43 S/m (+/- 20%), respectively.
研究了悬浮在等渗溶液中并受到线偏振电场作用的人类和骆驼红细胞的频率依赖性取向。人类红细胞可表示为扁球体（3.9:3.9:1.1微米），有两种可区分的取向，而骆驼细胞近似为具有三个不同轴的椭球体（4.0:2.0:1.1微米）。在适当的实验条件下，观察到了人类细胞的两种取向以及骆驼细胞的所有三种取向。使用一种将细胞膜视为理想电容的薄共焦层的理论细胞模型来预测取向光谱。预测光谱在频率范围和取向顺序上与实验数据吻合良好。通过调整这些重要参数的值以实现理论曲线与数据的最佳拟合，获得了细胞内部电导率和介电常数的估计值。通过使用这种方法，估计骆驼红细胞的内部电导率为0.26 S/m（±20%），而纤细裸藻的有效内部介电常数和电导率分别估计为120（±10%）和0.43 S/m（±20%）。
