Electromechanical Properties and Deformation of Biomembranes

哺乳动物、鸟类和爬行动物的细胞外缘有一层薄薄的细胞膜，由脂肪分子（脂质）组成。细胞内部的带电分子浓度与细胞外部不同，导致细胞膜上的电场改变了其机械性能。细胞膜的力学特性对细胞的功能有深远的影响。这项研究将通过实验来确定暴露在电场下细胞膜的机械性能是如何变化的。实验结果将使用“壳理论”的工程方法进行建模，壳理论可以模拟薄材料的曲率对其机械性能的影响。跨质膜的电位差对所有活细胞来说都是共同的，并且对生理功能至关重要，例如细胞间通信的动作电位的产生。虽然细胞电活动的基础已经很好地建立了（例如动作电位的霍奇金-赫胥黎模型），但电压和膜变形之间的耦合却受到了有限的关注。为了填补这一空白，将对外外加电场下仿生膜的理论和实验相结合的研究进行研究。具体而言，该研究旨在确定膜电压、膜特性（如弯曲刚度、张力和自发曲率）和膜形状之间的关系。该项目将理论与实验相结合，分析了外加电场中小的热驱动双层波动和大的屈曲样变形。该项目的变革影响在于其对生物膜形状和电压之间动态耦合的开创性研究；我们的发现将揭示与涉及可兴奋细胞的广泛生理过程相关的新物理学。

The cells of mammals, birds and reptiles have as their outer edge a thin layer, a cell membrane, that is composed of fatty molecules (lipids). The inside of the cell has a different concentration of charged molecules from the outside of the cell, resulting in an electric field across the membrane that changes its mechanical properties. The mechanical properties of the cell membrane have a profound effect upon how the cell functions. The research will determine by experiment how the mechanical properties of a cell membrane change as the result of exposure to electrical fields. The results of the experiments will be modeled using the engineering methods of 'shell theory' which can model the effects of the curvature of a thin material on its mechanical properties.An electric potential difference across the plasma membrane is common to all living cells and is essential to physiological functions such as generation of action potentials for cell-to-cell communication. While the basics of cell electrical activity are well established (e.g. the Hodgkin-Huxley model of the action potential), the coupling between voltage and membrane deformation has received limited attention. To fill this void, a combined theoretical and experimental study of biomimetic membranes in externally applied electric fields will be studied. Specifically, the research seeks to determine the relation between membrane voltage, membrane properties such as bending rigidity, tension, and spontaneous curvature, and membrane shape. The project integrates theory and experiment to analyze both the small thermally-driven bilayer undulations and the large buckling-like deformations in an applied electric field. The transformative impact of the project lies in its pioneering research of the dynamic coupling between shape and voltage of biomembranes; our findings will uncover new physics relevant to a broad range of physiological processes involving excitable cells.