Dynamic interfacial properties of human tear-lipid films and their interactions with model-tear proteins in vitro.

摘要: This review summarizes the current state of knowledge regarding interfacial properties very complex biological colloids, specifically, human meibum and tear lipids, their interactions with proteins similar to found in aqueous part tears. Tear lipids spread as thin films over surface tear-film play crucial roles stability overall ocular-surface health. The vast majority papers published date report meibum-lipid monolayers on various sub-phases, often containing model proteins, Langmuir trough. However, it is well established that natural ocular exist multilayered a thickness between 30 100nm, much disparate from 1 2nm thick monolayers. We employed sessile-bubble tensiometry study dynamic rheological reconstituted tear-lipid films. Small amounts (0.5-1μg) were deposited an air-bubble produce range 30-100nm corresponding lipid Thus, we able overcome major Langmuir-trough method limitations because can be safely harvested only minute, sub-milligram quantities, insufficient for through studies. Sessile-bubble demonstrated versatile tool assessing conventional synthetic surfactants adsorption/desorption dynamics at air-aqueous solution interface. (Svitova T., Weatherbee M., Radke C.J. Dynamics surfactant sorption air/water interface: continuous-flow tensiometry. J. Colloid Interf. Sci. 2003;261:1170-179). augmented flow-sessile-bubble setup, step-strain relaxation module high-precision syringe pump generate larger slow area expansions-contractions, was developed our this uniquely suitable examination lipid-film properties. Recently compellingly proven chemical composition extracted whole tears substantially different lipids. To exact, healthy contain 8-16% polar lung they are mostly double-tailed phospholipids, C16 longer alkyl chains. Rationally, one would assume results obtained devoid surface-active components such and, above all, form monolayers, not pertinent or useful elucidating behavior averaged 60-nm vivo. advantage technique, using small amount required attain films, unlocks prospect evaluating comparing collected single individual, typically 100-150μg. sharp contrast several milligrams build equally experiments. studies provided in-depth understanding mechanisms responsible Here summarize recent publications latest findings properties, composition, interaction mimicking tear-aqueous phase.