Effects of spontaneous curvature on interfacial adsorption and collapse of phospholipid monolayers
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View abstract on PubMed
Summary
This summary is machine-generated.Pulmonary surfactant's rapid adsorption is linked to its tendency for negative curvature, but this also accelerates collapse. Planar structures, despite negative curvature, do not prevent collapse, highlighting the importance of curvature dynamics.
Area Of Science
- Biophysics
- Materials Science
- Surface Chemistry
Background
- Pulmonary surfactant requires rapid adsorption to the alveolar air/water interface and slow collapse under compression for effective function.
- Cylindrical monolayers of the inverse hexagonal (H<sub>II</sub>) phase, characterized by negative curvature, exhibit rapid adsorption.
- Formation of H<sub>II</sub> structures can disrupt phospholipid chain-packing, while lamellar structures optimize it.
Purpose Of The Study
- To investigate whether planar lamellar bilayers, formed by phospholipids with negative spontaneous curvature, exhibit rapid adsorption and slow collapse.
- To determine the role of spontaneous curvature and the presence of the H<sub>II</sub> phase in surfactant adsorption and collapse dynamics.
Main Methods
- Utilized binary mixtures of dioleoyl phosphatidylcholine-dioleoyl phosphatidylethanolamine (DOPC-DOPE) with varying mole fractions of DOPE (X<sub>PE</sub>).
- Employed small-angle X-ray scattering (SAXS) to analyze the structural phases (lamellar vs. H<sub>II</sub>) of the phospholipid mixtures.
- Measured adsorption rates and collapse behaviors of the prepared phospholipid samples.
Main Results
- Increased mole fractions of DOPE (higher X<sub>PE</sub>) led to more negative spontaneous curvature.
- Samples with higher X<sub>PE</sub> demonstrated accelerated adsorption but also faster collapse.
- Small-angle X-ray scattering confirmed the presence of only lamellar structures, with no detectable H<sub>II</sub> phase within the studied range.
Conclusions
- The innate tendency of phospholipids to form negative curvature is crucial for rapid adsorption, more so than the presence of the H<sub>II</sub> phase.
- Planar lamellar structures are insufficient to mitigate the collapse tendency driven by spontaneous curvature.
- Adsorption and collapse likely involve rate-limiting transient structures exhibiting significant negative curvature.
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