Model Lung Surfactant Films: Why Composition Matters

Lung surfactant replacement therapies, Survanta and Infasurf, and two lipid-only systems both containing saturated and unsaturated phospholipids and one containing additional palmitic acid were used to study the impact of buffered saline on the surface activity, morphology, rheology, and structure o...

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Bibliographic Details
Published in:	Langmuir Vol. 32; no. 41; pp. 10767 - 10775
Main Authors:	Selladurai, Sahana L, Miclette Lamarche, Renaud, Schmidt, Rolf, DeWolf, Christine E
Format:	Journal Article
Language:	English
Published:	United States American Chemical Society 18-10-2016
Subjects:	Biological and Environmental Phenomena at the Interface lipids MATERIALS SCIENCE phase transitions surfactants transition metals viscosity
Online Access:	Get full text
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Summary:	Lung surfactant replacement therapies, Survanta and Infasurf, and two lipid-only systems both containing saturated and unsaturated phospholipids and one containing additional palmitic acid were used to study the impact of buffered saline on the surface activity, morphology, rheology, and structure of Langmuir monolayer model membranes. Isotherms and Brewster angle microscopy show that buffered saline subphases induce a film expansion, except when the cationic protein, SP-B, is present in sufficient quantities to already screen electrostatic repulsion, thus limiting the effect of changing pH and adding counterions. Grazing incidence X-ray diffraction results indicate an expansion not only of the liquid expanded phase but also an expansion of the lattice of the condensed phase. The film expansion corresponded in all cases with a significant reduction in the viscosity and elasticity of the films. The viscoelastic parameters are dominated by liquid expanded phase properties and do not appear to be dependent on the structure of the condensed phase domains in a phase separated film. The results highlight that the choice of subphase and film composition is important for meaningful interpretations of measurements using model systems.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 AC02-06CH11357; 03977-2014; 8071 USDOE Office of Science (SC) Natural Science and Engineering Research Council Canada Foundation for Innovation
ISSN:	0743-7463 1520-5827
DOI:	10.1021/acs.langmuir.6b02945