Organization of Lipids in the Tear Film: A Molecular- Level View

0427289 - ÚFCH JH 2015 RIV US eng J - Journal Article
Wizert, A. - Iskander, D. R. - Cwiklik, Lukasz
Organization of Lipids in the Tear Film: A Molecular- Level View.
PLoS ONE. Roč. 9, č. 3 (2014), e92461. ISSN 1932-6203. E-ISSN 1932-6203
Institutional support: RVO:61388955
Keywords : DRY EYE DISEASE * CONTACT-LENS WEARERS * COARSE-GRAINED MODEL
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.234, year: 2014

Biophysical properties of the tear film lipid layer are studied at the molecular level employing coarse grain molecular dynamics (MD) simulations with a realistic model of the human tear film. In this model, polar lipids are chosen to reflect the current knowledge on the lipidome of the tear film whereas typical Meibomian-origin lipids are included in the thick nonpolar lipids subphase. Simulation conditions mimic those experienced by the real human tear film during blinks. Namely, thermodynamic equilibrium simulations at different lateral compressions are performed to model varying surface pressure, and the dynamics of the system during a blink is studied by non-equilibrium MD simulations. Polar lipids separate their nonpolar counterparts from water by forming a monomolecular layer whereas the non-polar molecules establish a thick outermost lipid layer. Under lateral compression, the polar layer undulates and a sorting of polar lipids occurs. Moreover, formation of three-dimensional aggregates of polar lipids in both non-polar and water subphases is observed. We suggest that these three-dimensional structures are abundant under dynamic conditions caused by the action of eye lids and that they act as reservoirs of polar lipids, thus increasing stability of the tear film.
Permanent Link: http://hdl.handle.net/11104/0232879