Mapping the Structure-Function Relationships of the Tear Film Lipid Layer by Grazing Incidence X-ray Diffraction on its Central Lipid Specie

We apply for 18 shifts at ID10-EH1 to conduct grazing incidence X-ray diffraction (GIXD) and reflectivity (XRR) experiments on Langmuir films of tear film lipids. These relate to the tear film lipid layer (TFLL) which covers the tear film at the ocular surface. Its function is poorly understood due to open questions on the molecular level organization and structure. These can be answered by studying the self-assembly of monolayers of selected TFLL lipids on an aqueous interface. Our unique lipid library containing representatives from the major TFLL lipid classes is well suited for this task. In a preselection process we have studied the surface potential and pressure profiles of different species and selected the most promising ones for GIXD and XRR studies. The ID10-EH1 is specialized for the surface studies enabling thus generation of ground-breaking scientific results. The results play a role in combating ocular surface diseases, which constitute a severe global societal burden.