Trevorah Ryan M, Stubb Henrik, Viljanen Mira, Mäkinen Henrik, Viitaja Tuomo, Sevón Julia, Konovalov Oleg, Jankowski Maciej, Hemmerle Arnaud, Ekholm Filip S, Svedström Kirsi J
Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland.
Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland.
Langmuir. 2025 Sep 9;41(35):23353-23361. doi: 10.1021/acs.langmuir.5c01920. Epub 2025 Aug 24.
The tear film lipid layer (TFLL) is the outermost layer of the tear film and forms a barrier between the eye and the environment. While the TFLL is important in maintaining ocular surface health, there remains a curtain of mystery surrounding its structure and function on the molecular level. This is the result of the complex composition of the lipid film, the challenging dynamic environment in which it is present and missing molecular level information on the properties displayed by its lipid constituents. We recently assessed whether state-of-the-art surface X-ray scattering techniques can be employed to study the properties of films formed by individual tear film lipids and found this approach to bear significant potential in addressing the current unknown parameters of these substrates. Herein, we perform a follow-up study utilizing an expanded library of molecules in order to uncover general trends displayed by distinct tear film lipid classes. Through the use of grazing incidence X-ray diffraction and X-ray reflectivity techniques, we determine the lattice distances, molecular tilt angles and film thickness of representative lipids featuring variations in branching patterns and chain lengths and take an important step toward a deeper understanding of the molecular level structure and function of individual tear film lipids.
泪膜脂质层（TFLL）是泪膜的最外层，在眼睛与外界环境之间形成一道屏障。虽然TFLL对维持眼表健康至关重要，但在分子水平上，其结构和功能仍存在一层神秘的面纱。这是由于脂质膜的复杂组成、其所处的具有挑战性的动态环境以及缺乏关于其脂质成分所表现出特性的分子水平信息所致。我们最近评估了是否可以采用先进的表面X射线散射技术来研究由单个泪膜脂质形成的膜的特性，并发现这种方法在解决这些底物当前未知参数方面具有巨大潜力。在此，我们利用一个扩展的分子库进行后续研究，以揭示不同泪膜脂质类别所呈现的一般趋势。通过使用掠入射X射线衍射和X射线反射率技术，我们确定了具有不同分支模式和链长变化的代表性脂质的晶格间距、分子倾斜角和膜厚度，并朝着更深入理解单个泪膜脂质的分子水平结构和功能迈出了重要一步。
