Marszalek P, Zielinsky J J, Fikus M, Tsong T Y
Department of Biochemistry, University of Minnesota, St. Paul 55108.
Biophys J. 1991 May;59(5):982-7. doi: 10.1016/S0006-3495(91)82312-8.
Marszalek, P., J. J. Zielinsky, and M. Fikus (1989. Bioelectrochem. Bioenerg. 22:289-298) have described a novel design for measuring the complete dielectrophoretic spectrum of a single cell. From the analysis of the dielectrophoretic spectrum, the membrane conductivity, sigma membr, and the membrane dielectric permittivity, epsilon membr, of the cell may be determined according to the theory of dielectrophoresis described by Sauer, F. A. (1985. Interactions between Electromagnetic Field and Cells. A. Chiabrera, C. Nicolini, and H.P. Schwan, editors. Plenum Publishing Corp., New York. 181-202). At Fo, the net force experienced by a single shell sphere in a nonuniform periodic field is zero, and the sphere ceases to move in the field. In other words, at Fo, the effective polarizability, chi eff, of the sphere (the polarizability of sphere minus the polarizability of the medium) is equal to zero. For biological cells in high conductivity medium, e.g., the isotonic saline, sigma membr falls below 2 x 10(-6) S m-1, where Fo becomes insensitive to sigma membr, and the method becomes impractical. In a low conductivity medium, 0.3 M sucrose, sigma membr of cells is generally higher and the method may be applied. Assuming a membrane thickness of 9 nm, epsilon membr of Neurospora crassa slime cells was determined to be in the range of 8.3-9.4 epsilon o, and of myeloma Tib9 to be 9.4 epsilon o, epsilon o being the dielectric permittivity of the free space. The values for the slime cells were compared with values obtained by the dielectric spectroscopy method which measures average values for cells in suspension.
马尔沙莱克、P.、J. J. 齐林斯基和M. 菲库斯（1989年。《生物电化学与生物能量学》22卷：289 - 298页）描述了一种用于测量单个细胞完整介电泳谱的新颖设计。通过对介电泳谱的分析，可根据索尔，F. A.（1985年。《电磁场与细胞之间的相互作用》。A. 基亚布雷拉、C. 尼科利尼和H. P. 施万编辑。普伦出版社，纽约。181 - 202页）所描述的介电泳理论来确定细胞的膜电导率，σ膜，以及膜介电常数，ε膜。在F₀时，单个壳层球体在非均匀周期场中所经历的净力为零，球体在该场中停止移动。换句话说，在F₀时，球体的有效极化率，χeff（球体的极化率减去介质的极化率）等于零。对于处于高电导率介质中的生物细胞，例如等渗盐水，σ膜低于2×10⁻⁶ S m⁻¹，此时F₀对σ膜不敏感，该方法变得不实用。在低电导率介质，0.3 M蔗糖中，细胞的σ膜通常较高，该方法可以应用。假设膜厚度为9纳米，粗糙脉孢菌黏液细胞的ε膜被确定在8.3 - 9.4ε₀范围内，骨髓瘤Tib9细胞的ε膜为9.4ε₀，ε₀为自由空间的介电常数。将黏液细胞的值与通过介电谱法获得的值进行了比较，介电谱法测量的是悬浮细胞的平均值。
