The outer layer of the skin, stratum corneum (SC) is an efficient transport barrier and it tolerates mechanical deformation. At physiological conditions, the majority of SC lipids are solid, while the presence of a small amount of fluid lipids is considered crucial for SC barrier and material properties. Here we use solid-state and diffusion nuclear magnetic resonance to characterize the composition and molecular dynamics of the fluid lipid fraction in SC model lipids, focusing on the role of the essential SC lipid CER EOS, which is a ceramide esterified omega-hydroxy sphingosine linoleate with very long chain. We show that both rigid and mobile structures are present within the same CER EOS molecule, and that the linoleate segments undergo fast isotropic reorientation while exhibiting extraordinarily slow self-diffusion. The characterization of this unusual self-assembly in SC lipids provides deepened insight into the molecular arrangement in the SC extracellular lipid matrix and the role of CER EOS linoleate in the healthy and diseased skin.

中文翻译：

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同一角质层神经酰胺脂质分子内的固体和液体片段

皮肤的外层角质层 (SC) 是一种有效的运输屏障，它可以承受机械变形。在生理条件下，大多数 SC 脂质是固体，而少量流体脂质的存在被认为对 SC 屏障和材料特性至关重要。在这里，我们使用固态和扩散核磁共振来表征 SC 模型脂质中流体脂质部分的组成和分子动力学，重点关注基本 SC 脂质 CER EOS 的作用，它是一种神经酰胺酯化的 omega-羟基亚油酸鞘氨醇有很长的链条。我们表明刚性结构和移动结构都存在于同一个 CER EOS 分子中，并且亚油酸酯链段经历快速各向同性重新定向，同时表现出异常缓慢的自扩散。