Sabuncu A C, Stacey M, Craviso G L, Semenova N, Vernier P T, Leblanc N, Chatterjee I, Zaklit J
Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75205, USA.
Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
Bioelectrochemistry. 2018 Feb;119:84-91. doi: 10.1016/j.bioelechem.2017.09.001. Epub 2017 Sep 5.
Knowledge of the dielectric properties of biological cells plays an important role in numerical models aimed at understanding how high intensity ultrashort nanosecond electric pulses affect the plasma membrane and the membranes of intracellular organelles. To this end, using electrical impedance spectroscopy, the dielectric properties of isolated, neuroendocrine adrenal chromaffin cells were obtained. Measured impedance data of the cell suspension, acquired between 1kHz and 20MHz, were fit into a combination of constant phase element and Cole-Cole models from which the effect of electrode polarization was extracted. The dielectric spectrum of each cell suspension was fit into a Maxwell-Wagner mixture model and the Clausius-Mossotti factor was obtained. Lastly, to extract the cellular dielectric parameters, the cell dielectric data were fit into a granular cell model representative of a chromaffin cell, which was based on the inclusion of secretory granules in the cytoplasm. Chromaffin cell parameters determined from this study were the cell and secretory granule membrane specific capacitance (1.22 and 7.10μF/cm, respectively), the cytoplasmic conductivity, which excludes and includes the effect of intracellular membranous structures (1.14 and 0.49S/m, respectively), and the secretory granule milieu conductivity (0.35S/m). These measurements will be crucial for incorporating into numerical models aimed at understanding the differential poration effect of nanosecond electric pulses on chromaffin cell membranes.
了解生物细胞的介电特性对于旨在理解高强度超短纳秒电脉冲如何影响质膜和细胞内细胞器膜的数值模型起着重要作用。为此，使用电阻抗光谱法获得了分离的神经内分泌肾上腺嗜铬细胞的介电特性。在1kHz至20MHz之间采集的细胞悬液的测量阻抗数据，拟合为恒相位元件和科尔 - 科尔模型的组合，从中提取电极极化的影响。将每个细胞悬液的介电谱拟合为麦克斯韦 - 瓦格纳混合模型，并获得克劳修斯 - 莫索蒂因子。最后，为了提取细胞介电参数，将细胞介电数据拟合到一个代表嗜铬细胞的颗粒细胞模型中，该模型基于细胞质中包含分泌颗粒。本研究确定的嗜铬细胞参数为细胞和分泌颗粒膜的比电容（分别为1.22和7.10μF/cm）、排除和包括细胞内膜状结构影响的细胞质电导率（分别为1.14和0.49S/m）以及分泌颗粒环境电导率（0.35S/m）。这些测量对于纳入旨在理解纳秒电脉冲对嗜铬细胞膜的差异穿孔效应的数值模型至关重要。
