Abstract

Reflectometry and nonspecular (diffuse) X-ray scattering data are used to refine the structure parameters of planar multilayer films of saturated DPPC and DSPC phospholipids with thickness of about 400 Å formed on the surface of an aqueous suspension of silica nanoparticles about 27 nm in diameter. A consistent analysis of the scattering data shows that the hydrosol–lipid film–air structure consists of a monolayer of nanoparticles, a lamellar lipid layer, and an approximately half-filled (loose) phospholipid monolayer at the air interface. Model electron concentration profiles indicate the hydration of the lamellar structure at a level of about 6 H₂O molecules per lipid. In this case, water and Na⁺ cations are localized in the region of phosphocholine groups, which is in agreement with the results of molecular dynamics calculations of other authors. The observed roughness of the interfaces between lipid layers is at least 5 Å and is indicative of the presence of a 3–6-Å-wide noncapillary-wave structure. In our opinion, one of the possible applications of the described technology is coating the concave surface of a rotating hydrosol liquid with a lipid multilayer in an X-ray deflecting device with a whispering gallery mode.

中文翻译：

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平面磷脂多层的非镜面X射线散射

摘要

使用反射法和非镜面（漫射）X射线散射数据来完善饱和的DPPC和DSPC磷脂的平面多层膜的结构参数，该膜在直径约27 nm的二氧化硅纳米颗粒的水悬浮液表面上形成，厚度约为400Å 。对散射数据的一致分析表明，溶胶-脂质膜-空气结构由纳米颗粒的单层，层状脂质层和空气界面处大约一半填充的（松散的）磷脂单层组成。模型电子浓度曲线表明层状结构的水合水平为每个脂质约6 H ₂ O分子。在这种情况下，水和Na ⁺阳离子位于磷酸胆碱基团区域内，这与其他作者的分子动力学计算结果一致。观察到的脂质层之间的界面粗糙度至少为5Å，表明存在3-6Å宽的非毛细管波结构。我们认为，所描述技术的可能应用之一是在带有回音壁模式的X射线偏转设备中，用脂质多层膜覆盖旋转的水溶胶液体的凹面。