STRUCTURAL INVESTIGATIONS OF HUMAN STRATUM-CORNEUM BY SMALL-ANGLE X-RAY-SCATTERING
STRUCTURAL INVESTIGATIONS OF HUMAN STRATUM-CORNEUM BY SMALL-ANGLE X-RAY-SCATTERING
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DOI：
10.1111/1523-1747.ep12492217
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发表时间：
1991-12-01
影响因子：
6.5
通讯作者：
BRAS, W
中科院分区：
文献类型：
--
作者：
BOUWSTRA, JA;GOORIS, GS;BRAS, W
用小角X射线散射（SAXS）研究了人皮肤角质层的结构。在室温下的散射曲线的特征在于在低散射矢量（Q < 0.8 nm-1）和两个复杂的衍射峰起源于层状结构的脂质的强强度。角质层中的层状脂质结构在65 ℃至75 ℃之间转变为无序结构，在相同的温度区域发生热脂质转变。冷却至室温后，发生至少一部分脂质的重结晶，之后仅可检测到一个重复距离为13.4 nm的晶胞。将结晶后角质层的散射曲线与重结晶前角质层的散射曲线进行比较，得出以下结论：在原始曲线中，脂质排列在两个重复距离为6.4 nm和13.4 nm的晶胞中。从模型计算看来，后者的单位电池由一个以上的双层。测量了不同水合程度的角质层的散射曲线。角质层含水量在6%w/w和60%w/w（完全水合）之间的变化不会导致双层溶胀，但角质层水合至60%w/w时获得的散射曲线与较低水合水平下的散射曲线不同：60%w/w时的散射曲线仅显示出对应于重复距离为6.4 nm的晶胞的衍射峰。这一观察结果意味着，在非常高的水含量下，一部分脂质的有序性降低，这可以解释水在角质层中的强渗透增强作用。
The structure of human stratum corneum was investigated with small-angle X-ray scattering (SAXS). At room temperature the scattering curve was characterized by a strong intensity at low scattering vector (Q < 0.8 nm-1) and two complicated diffraction peaks originating from a lamellar structure of the lipids. The lamellar lipid structure in the stratum corneum transformed to a disordered structure between 65-degrees-C and 75-degrees-C, the same temperature region at which a thermal lipid transition occurred. After cooling down to room temperature a recrystallization of at least a part of the lipids took place, after which only one unit cell with a repeat distance of 13.4 nm could be detected. Comparison of the scattering curve of the stratum corneum after crystallization with the scattering curve of the stratum corneum before recrystallization leads to the conclusion that in the original curve the lipids are arranged in two unit cells with repeat distances of 6.4 nm and 13.4 nm. From model calculations it appears that the latter unit cell consists of more than one bilayer. The scattering curves of stratum corneum hydrated to various levels were measured. A change in the water content of stratum corneum between 6% w/w and 60% w/w (fully hydrated) did not result in swelling of the bilayers, but the scattering curve obtained with stratum corneum hydrated to 60% w/w differed from those at lower hydration levels: the scattering curve at 60% w/w showed only the diffraction peaks corresponding to a unit cell with a repeat distance of 6.4 nm. This observation implies that the ordering of a part of the lipids is reduced at very high water contents, which may explain the strong penetration-enhancing effects of water in the stratum corneum.