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Adsorption of Phospholipids at the Air-Water Surface.

Authors :
Bai X
Xu L
Tang JY
Zuo YY
Hu G
Source :
Biophysical journal [Biophys J] 2019 Oct 01; Vol. 117 (7), pp. 1224-1233. Date of Electronic Publication: 2019 Aug 28.
Publication Year :
2019

Abstract

Phospholipids are ubiquitous components of biomembranes and common biomaterials used in many bioengineering applications. Understanding adsorption of phospholipids at the air-water surface plays an important role in the study of pulmonary surfactants and cell membranes. To date, however, the biophysical mechanisms of phospholipid adsorption are still unknown. It is challenging to reveal the molecular structure of adsorbed phospholipid films. Using combined experiments with constrained drop surfactometry and molecular dynamics simulations, here, we studied the biophysical mechanisms of dipalmitoylphosphatidylcholine (DPPC) adsorption at the air-water surface. It was found that the DPPC film adsorbed from vesicles showed distinct equilibrium surface tensions from the DPPC monolayer spread via organic solvents. Our simulations revealed that only the outer leaflet of the DPPC vesicle is capable of unzipping and spreading at the air-water surface, whereas the inner leaflet remains intact and forms an inverted micelle to the interfacial monolayer. This inverted micelle increases the local curvature of the monolayer, thus leading to a loosely packed monolayer at the air-water surface and hence a higher equilibrium surface tension. These findings provide novel insights, to our knowledge, into the mechanism of the phospholipid and pulmonary surfactant adsorption and may help understand the structure-function correlation in biomembranes.<br /> (Copyright © 2019 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

Details

Language :
English
ISSN :
1542-0086
Volume :
117
Issue :
7
Database :
MEDLINE
Journal :
Biophysical journal
Publication Type :
Academic Journal
Accession number :
31519299
Full Text :
https://doi.org/10.1016/j.bpj.2019.08.022