磷脂双层膜稳定性的理论分析

The Theoretical Analysis on the Stability of Lipid Bilayers

目的:越来越多磷脂双层膜的原子力显微镜扫描力谱显示溶液离子浓度对磷脂双层膜稳定性有很大影响,本文从理论角度研究溶液离子浓度对磷脂双层膜稳定性的影响,同时解释两个基于不同模型模拟结果差别的原因。方法:主要根据磷脂分子极性端带电特性,将极性端看作偶极子,然后基于偶极-偶极相互作用理论以及泊松-玻尔兹曼理论解决以上问题。结论:随着离子浓度的增加,磷脂双层膜趋于更加稳定;基于两个不同模型模拟结果差别的原因是高浓度溶液的强静电屏蔽作用。

Objective： The nanomechanical response of lipid bilayers has been studied by force spectroscopy with atomic force microscopy, which indicates that ion strength has great effects on the stability of lipid bilayers. The effects of the ionic strength on the stability of lipid bilayers will be investigated theoretically in this paper; at the same time, what causes the difference between the simulation results of the two models will be disclosed. Method： According to the electrical characteristics of polar head in lipid molecule, the polar head will be regarded as dipole. Based on dipole-dipole interaction theory and Poisson-Boltzmann theory, the issues mentioned above will be discussed. Conclusion： With the ion strength increasing, the lipid bilayers become more stable. It is the strong electro-static screening effects that cause the difference between the simulation results of two models.