Unveiling Interfacial Properties of Surfactant Assemblies Mimicking Healthy and Diseased States in Lung Membranes

Lipid-protein complexes conform the basis of pulmonary surfactants covering the respiratory surface and mediating gas exchange in lungs, yet how they contribute to alveoli membrane functions in healthy and diseased conditions is not sufficiently understood. Alveolar stability appears to be controlled by the passive elastic properties of the pulmonary tissue as well as the mechanical performance of the surfactant membranes and an unbalance of these is associated with different respiratory dysfunctions and pathologies. Cardiolipin is a mitochondrial lipid overexpressed in mammalian lungs infected by bacterial pneumonia, likely to play a role in alveolar stability. We performed structural and mechanical characterization by GISAXS, AFM and Fast Force Mapping on lipid-based mimicking pulmonary membranes in healthy and diseased states. Our preliminary results unveiled that pulmonary membranes suffer structural transformations induced by cardiolipin and calcium ions. Membrane contacts, or stalks, might induce a significant increase in oxygen gas permeation that can lead to imbalance in alveoli gas exchange.