Browsing by Author "Hynynen, Antti"

The tear film is a thin liquid layer enveloping the cornea and conjunctiva. It serves as a crucial protective barrier safeguarding the ocular surface from environmental factors. Its functions also include ensuring optimal hydration and maintaining a consistently smooth optical surface. The tear film consists of three discernible layers. The outermost layer is the remarkably thin tear film lipid layer, measured on the nanometer scale, yet crucial for impeding evaporation and maintaining ocular surface homeostasis. The tear film lipid layer forms from meibum: a complex mixture of lipids secreted by Meibomian glands. Meibum mainly consists of lipids from five different classes, with wax esters constituting about 50 % of meibum’s composition. The majority of tear film lipids are branched. Branched lipids are methyl-branched either from the penultimate or antepenultimate carbon, with the former being more common. Due to challenges in obtaining sufficient and uncontaminated meibum samples, there is a high demand for synthetically produced lipids. Pure samples of lipids of varying structures are needed as standards in studies regarding meibum composition. Additionally, lipids and lipid mixtures are required for biophysical studies concerning tear film models and researching the molecular mechanisms associated with ocular surface diseases. Given the demand for various tear film lipids, it is surprising that there have been no prior attempts to synthesize branched lipid species or study their effect on lipid assembly, despite their prevalence in meibum. To meet the demand for various tear film lipids, especially branched species, we aimed to design a synthetic approach capable of producing a wide range of such tear film lipid analogs. This method proved successful in synthesizing the most abundant tear film lipid, the iso-branched wax ester C18:1/26:0. The results of this synthesis are presented in this thesis.