Effects of Spontaneous Curvature on Interfacial Adsorption and Collapse of Phospholipid Monolayers

Authors

Bret A. Brandner, Oregon Health & Science University
Shankar B. Rananavare, Portland State UniversityFollow
Stephen B. Hall, Oregon Health & Science University

Document Type

Pre-Print

Publication Date

10-22-2024

Abstract

To function effectively, pulmonary surfactant must adsorb rapidly to the alveolar air/water interface but avoid collapse from the surface when compressed to high interfacial densities. Prior studies show that phospholipids in the cylindrical monolayers of the inverse hexagonal (HII) phase adsorb quickly. The monolayers have negative curvature, defined by the concave shape of the hydrophilic face. Formation of the HII structures, however, involves significant disruption of chain-packing. Samples with significant spontaneous curvature, formed in the absence of applied force, may nonetheless have lamellar structures that optimize chain-packing. The experiments here tested whether planar lamellar bilayers formed by phospholipids with negative spontaneous curvature might adsorb rapidly but collapse slowly. Prior studies have shown that binary mixtures of dioleoyl phosphatidylcholine-dioleoyl phosphatidylethanolamine (DOPC-DOPE) with higher mol fractions of DOPE (XPE) have more negative spontaneous curvature. Samples of DOPC-DOPE with higher XPE studied here adsorbed more rapidly but also collapsed more quickly. Over that range of XPE, small-angle X-ray scattering showed only lamellar structures. The HII phase was undetectable. The results suggest that the innate tendency of the phospholipids to form curvature has primary importance for adsorption rather than the presence of the HII phase. Planar structures are insufficient to minimize the tendency of spontaneous curvature to promote collapse. These findings are consistent with adsorption and collapse that occur via rate-limiting transient structures with significant negative curvature.

Rights

Copyright © 2024 the American Physiological Society.

Description

This is the publisher's PDF archived here with a 12 month embargo

Locate the Document

https://doi.org/10.1152/ajplung.00193.2024

DOI

10.1152/ajplung.00193.2024

Persistent Identifier

https://archives.pdx.edu/ds/psu/42725

Citation Details

Brandner, B. A., Rananavare, S. B., & Hall, S. B. (2024). Effects of Spontaneous Curvature on Interfacial Adsorption and Collapse of Phospholipid Monolayers. American Journal of Physiology-Lung Cellular and Molecular Physiology.