摘要: 生物阻抗谱是一种非侵入式、免标记的、能够定量分析的检测技术，将其应用于生物细胞及组织的生理、病理分析中具有很大优势。本文采用数值仿真的方式研究了单细胞电学特性与其结构之间的关系，并通过实验进行了验证。根据细胞的生理特征，依据细胞的双壳模型与单壳模型理论分别建立了不同种类细胞的电学模型，研究了细胞种类、细胞膜、细胞核对细胞电学特性的影响。数值分析结果表明：1）细胞结构尺寸的变化引起细胞电学特性的改变，因此，依据细胞电学特性能够准确实现细胞分类；2）柯尔-柯尔 (Cole-Cole)图上高频与低频的两个半圆弧分别是由细胞质或细胞外液的离子极化、细胞膜与细胞外液之间的界面极化所引起的；3）细胞核大小对测量阻抗的影响主要在低频段，是由细胞核与细胞内液的界面极化引起的，当存在细胞膜且当细胞核的核质比小于0.25时可忽略其影响。为验证仿真结果，对20%不同活性的酵母菌进行了实验。实验结果表明，运用本文建立的细胞电学模型，可以准确检测细胞的不同活性。该方法对实现细胞的精准电阻抗检测提供了理论依据，具有重要的应用价值。
Electrical Characteristics of Cells with Electrical Impedance Spectroscopy
- Received Date:
24 April 2020
Abstract: Bioelectrical impedance spectroscopy is a noninvasive, label-free and quantitative detection technology, which has great advantages in the physiological and pathological analysis of biological cells and tissues. In this paper, the relationship between the electrical properties of a single cell and its structure is studied by numerical simulation. Moreover, experiments are conducted to verify the simulation results. For simulation, three single cell models are used to express its structure. Among of the three models, No Shell Model (NS) is proposed in this paper to study the influence of cell membrane on bioelectrical impedance spectroscopy. In addition, the effects of cell type, cell membrane and cell nucleus on its electrical properties are studied by simulation based on Single Shell Model (SS) and Two Shell Model (TS). The simulation results show that: 1) the electrical characteristics of cells can reflect its structure, therefore, the cell type can be accurately distinguished by its electrical characteristics; 2) the high frequency part of the Cole-Cole Plot is caused by ionic polarization of cytoplasm or extracellular fluid, and the low frequency part of the Cole-Cole Plot is caused by interface polarization between cell membrane and the extracellular fluid; 3）The influence of cell nucleus size on impedance measurement is mainly in the low frequency range, which is caused by the polarization of the interface between cell nucleus and intracellular fluid, and when the nucleocytoplasmic ratio is less than 0.25, the effect of nuclear size on impedance analysis could be ignored. Finally, an experiment was conducted on 20% yeasts suspension with different activity to verify the simulation results. It is known that the cell membranes of dead yeasts are destroyed, however, living yeasts have completed cell structures. The structure difference between living and dead yeast is distinguished by electrical impedance spectroscopy through numerical simulation. The experimental results are consistent with the simulation results, which verifies the fact that the high frequency part of the Cole-Cole Plot is caused by ionic polarization of cytoplasm or extracellular fluid, and the low frequency part of the Cole-Cole Plot is caused by interface polarization between cell membrane and the extracellular fluid.