Model Lung Surfactant Films: Why Composition Matters
| Autor: | Rolf Schmidt, Sahana L. Selladurai, Christine E. DeWolf, Renaud Miclette Lamarche |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Langmuir Brewster's angle Chromatography 010304 chemical physics 02 engineering and technology Surfaces and Interfaces 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Viscoelasticity symbols.namesake Membrane chemistry Pulmonary surfactant Rheology Chemical engineering 0103 physical sciences Monolayer Electrochemistry symbols General Materials Science Counterion 0210 nano-technology Spectroscopy |
| Zdroj: | Langmuir : the ACS journal of surfaces and colloids. 32(41) |
| ISSN: | 1520-5827 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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