Biophysical Characterization of Tear Film Biomimetics: Interactions of Major Polar Lipids and Proteins

Date
2017
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Abstract
The tear film is a multilayered structure that protects the corneal epithelium from stress and damage, and allows for clear vision. A lipid layer shields the primarily aqueous portion of the tear film from the external environment. A polar lipid layer provides an interface between the aqueous layer and a thick nonpolar lipid layer. Dipalmitoylphosphatidylcholine, dipalmitoylphosphatidylethanolamine, palmitoyl-glucocerebroside, palmitoylsphingomyelin, and dipalmitoylphosphatidylserine have been previously identified as polar lipids in whole tear samples. Langmuir trough monolayer experiments were used to assess how major tear film proteins lysozyme, lactoferrin, and tear lipocalin affect the stability and elasticity of the pure lipids and lipid mixtures. Pure lipids and lipid mixtures all displayed high stability and rigidity in the tear film surface pressure range of 20 to 35 mN/m. Biologically relevant concentrations of lysozyme and lactoferrin (> 0.2 mg/mL) appeared to fluidize a quinary lipid mixture. Low concentrations of lipocalin may destabilize polar lipid films.
Description
Keywords
Biology, Biology--Molecular, Biophysics, Biochemistry
Citation
Haley, D. A. (2017). Biophysical Characterization of Tear Film Biomimetics: Interactions of Major Polar Lipids and Proteins (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25136