Solid-state NMR has great potential for investigating molecular structure, dynamics, and organization of the stratum corneum, the outer 10–20 μm of the skin, but is hampered by the unfeasibility of isotope labelling as generally required to reach sufficient signal-to-noise ratio for the more informative multidimensional NMR techniques. In this preliminary study of pig stratum corneum at 35 °C and water-free conditions, we demonstrate that cryogenic probe technology offers sufficient signal boost to observe previously undetectable minor resonances that can be uniquely assigned to fluid cholesterol, ceramides, and triacylglycerols, as well as enables 1H–1H spin diffusion monitored by 2D 1H-13C HETCOR to estimate 1–100 nm distances between specific atomic sites on proteins and lipids. The new capabilities open up for future multidimensional solid-state NMR studies to answer long-standing questions about partitioning of additives, such as pharmaceutically active substances, between solid and liquid domains within the protein and lipid phases in the stratum corneum and the lipids of the sebum.

中文翻译：

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低温探针技术可实现角质层的多维固体 NMR，无需同位素标记


固体核磁共振在研究角质层（皮肤外层 10-20 μm）的分子结构、动力学和组织方面具有巨大潜力，但受到同位素标记的不可行性的阻碍，因为同位素标记通常需要达到足够的信噪比，才能为信息量更大的多维 NMR 技术提供足够的信噪比。在这项在 35 °C 和无水条件下对猪角质层进行的初步研究中，我们证明了低温探针技术提供了足够的信号增强，以观察以前无法检测到的微小共振，这些共振可以唯一地分配给液体胆固醇、神经酰胺和三酰基甘油，以及能够通过 2D 1H-13C HETCOR 监测 1H-1H自旋扩散，以估计蛋白质和脂质上特定原子位点之间的 1-100 nm 距离。这些新功能为未来的多维固体核磁共振研究开辟了道路，以回答长期存在的关于角质层蛋白质和脂质相和皮脂脂质内添加剂（如药物活性物质）在固液结构域之间分配的问题。