Division of Drug Delivery Technology, P.O. Box 9502, 2300 RA, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, The Netherlands.
Langmuir. 2010 Mar 16;26(6):4168-75. doi: 10.1021/la9047038.
The lipid matrix present in the human stratum corneum (the thin, uppermost layer of the skin) is considered to play a crucial role in the skin barrier function. The lipid matrix consists of ceramides, cholesterol, and free fatty acids. The 13 nm lamellar phase present in the lipid matrix of the stratum corneum is very characteristic and plays an important role in the skin barrier function. One subclass of ceramides with a linoleic acid linked to a very long acyl (referred to as EOS) plays a crucial role in the formation of the 13 nm lamellar phase. In this article, we focus on the lipid phase behavior of EOS mixed with cholesterol or with cholesterol and free fatty acids. Our studies reveal that an equimolar ratio of EOS, cholesterol, and free fatty acids forms a lamellar phase with a very long repeat distance of approximately 14.7 nm. This phase exhibits exceptional behavior in that in the thermotropic response the fatty acid chains and the ceramide chains undergo an order-disorder transition in different temperature ranges while part of the hydrocarbon chains of ceramides and fatty acids are mixing in the orthorhombic lattice. On the basis of these observations, a molecular model for the 14.7 nm phase has been proposed in which the lipids are organized in a lamellar phase with three different lipid layers in a symmetric unit cell.
人角质层（皮肤的最薄、最上层）中的脂质基质被认为在皮肤屏障功能中起着至关重要的作用。脂质基质由神经酰胺、胆固醇和游离脂肪酸组成。角质层脂质基质中存在的 13nm 层状相非常具有特征性，并且在皮肤屏障功能中起着重要作用。一类与非常长的酰基（称为 EOS）连接的亚油酸神经酰胺在 13nm 层状相的形成中起着至关重要的作用。在本文中，我们专注于 EOS 与胆固醇或胆固醇和游离脂肪酸混合的脂质相行为。我们的研究表明，EOS、胆固醇和游离脂肪酸的等摩尔比形成具有约 14.7nm 非常长重复距离的层状相。这种相表现出异常行为，即在热致响应中，脂肪酸链和神经酰胺链在不同的温度范围内经历有序-无序转变，而神经酰胺和脂肪酸的部分烃链在正交晶格中混合。基于这些观察结果，提出了一种用于 14.7nm 相的分子模型，其中脂质在具有三个不同脂质层的对称单元中组织成层状相。
