Mechanical properties of lipid bilayers: a note on the Poisson ratio
Mechanical properties of lipid bilayers: a note on the Poisson ratio
复制标题
脂质双层的机械特性：关于泊松比的注释
DOI：
10.1039/c9sm01290g
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发表时间：
2019
期刊：
影响因子：
3.4
通讯作者：
Nagle, John F.
中科院分区：
文献类型：
--
作者：
Terzi, M. Mert;Deserno, Markus;Nagle, John F.
我们研究了流体脂质双层的泊松比ν，即，面积应变如何与伴随它们的膜厚度（或等效地，体积）的变化相比较的问题。我们首先研究现有的实验结果的面积和体积的脂质膜的可压缩性。分析均匀薄流体片的线性弹性理论的框架内，使我们得出结论，脂膜变形是一个很好的近似体积保持，泊松比可能是约3%小于常见的软物质的限制。这些结果与DOPC膜在不同量的施加侧向应力下的原子模拟完全一致，为此，我们通过直接比较面积应变和体积应变来推导ν。为了评估横向均匀性的问题假设，我们还定义了深度分辨泊松比ν（z），并通过对同一组模拟的精细分析来确定它。我们发现，在整个膜的厚度，ν（z）是接近的假设均匀性导出的值，只有轻微的变化的边界统计意义。
We investigate the Poisson ratio ν of fluid lipid bilayers, i.e., the question how area strains compare to the changes in membrane thickness (or, equivalently, volume) that accompany them. We first examine existing experimental results on the area- and volume compressibility of lipid membranes. Analyzing them within the framework of linear elasticity theory for homogeneous thin fluid sheets leads us to conclude that lipid membrane deformations are to a very good approximation volume-preserving, with a Poisson ratio that is likely about 3% smaller than the common soft matter limit . These results are fully consistent with atomistic simulations of a DOPC membrane at varying amount of applied lateral stress, for which we instead deduce ν by directly comparing area- and volume strains. To assess the problematic assumption of transverse homogeneity, we also define a depth-resolved Poisson ratio ν(z) and determine it through a refined analysis of the same set of simulations. We find that throughout the membrane's thickness, ν(z) is close to the value derived assuming homogeneity, with only minor variations of borderline statistical significance.