Molecular dynamics simulations of stratum corneum lipid models:: fatty acids and cholesterol
Molecular dynamics simulations of stratum corneum lipid models:: fatty acids and cholesterol
复制标题
DOI：
10.1016/s0005-2736(01)00270-x
复制
发表时间：
2001-03-09
影响因子：
3.4
通讯作者：
Höltje, HD
中科院分区：
文献类型：
--
作者：
Höltje, M;Förster, T;Höltje, HD
我们报告了对角质层脂质的研究结果，角质层脂质是皮肤的主要屏障。应用了分子动力学模拟、热分析和 FTIR 测量。这项工作的主要目的是研究胆固醇对皮肤结构和动力学的影响。构建了两种分子模型：游离脂肪酸双层（硬脂酸、棕榈酸）和摩尔比为 1:1 的脂肪酸/胆固醇混合物。我们的模拟是在纳秒时间尺度上在恒定压力和温度下进行的。通过计算每个头基的表面积、构象特性、原子密度和脂肪酸的有序参数来表征所得模型结构。模拟分析表明，角质层脂质的游离脂肪酸部分在皮肤温度下保持高度有序的结晶状态。添加胆固醇时，相行为会受到强烈影响。胆固醇使脂肪酸的刚性相变得平滑：烃尾部的顺序（主要是最后八个键）减少，每个分子的面积变大，二面体的分数降低并且疏水厚度减小。模拟结果与 FTIR 分析和 NIR-FT 拉曼光谱的实验数据非常吻合。 (C) 2001 Elsevier Science B.V. 保留所有权利。
We report the results of an investigation on stratum corneum lipids, which present the main barrier of the skin. Molecular dynamics simulations, thermal analysis and FTIR measurements were applied. The primary objective of this work was to study the effect of cholesterol on skin structure and dynamics. Two molecular models were constructed, a free fatty acid bilayer (stearic acid, palmitic acid) and a fatty acid/cholesterol mixture at a 1:1 molar ratio. Our simulations were performed at constant pressure and temperature on a nanosecond time scale. The resulting model structures were characterized by calculating surface areas per headgroup, conformational properties, atom densities and order parameters of the fatty acids. Analysis of the simulations indicates that the free fatty acid fraction of stratum corneum lipids stays in a highly ordered crystalline state at skin temperatures. The phase behavior is strongly influenced when cholesterol is added. Cholesterol smoothes the rigid phases of the fatty acids: the order of the hydrocarbon tails (mainly of the last eight bonds) is reduced, the area per molecule becomes larger, the fraction of tl ans dihedrals is lower and the hydrophobic thickness is reduced. The simulation results are in good agreement with our experimental data from FTIR analysis and NIR-FT Raman spectroscopy. (C) 2001 Elsevier Science B.V. All rights reserved.