Evaluating the Impact of Hydrophobic Silicon Dioxide in the Interfacial Properties of Lung Surfactant Films

Abstract

The interaction of hydrophobic silicon dioxide particles (fumed silicon dioxide), as model air pollutants, and Langmuir monolayers of a porcine lung surfactant extract has been studied in order to try to shed light on the physicochemical bases underlying the potential adverse effects associated with pollutant inhalation. The surface pressure–area isotherms of lung surfactant (LS) films including increasing amounts of particles revealed that particle incorporation into LS monolayers modifies the organization of the molecules at the water/vapor interface, which alters the mechanical resistance of the interfacial films, hindering the ability of LS layers for reducing the surface tension, and reestablishing the interface upon compression. This influences the normal physiological function of LS as is inferred from the analysis of the response of the Langmuir films upon the incorporation of particles against harmonic changes of the interfacial area (successive compression–expansion cycles). These experiments evidenced that particles alter the relaxation mechanisms of LS films, which may be correlated to a modification of the transport of material within the interface and between the interface and the adjacent fluid during the respiratory cycle.

Lung surfactant as a biophysical assay for inhalation toxicology

“…Fumed (pyrogenic) silica is another variety of silica used in various applications due to its low density, high surface area, and high viscosity. Fumed silica nanoparticles were found to incorporate into LS monolayers in an LBT and disrupt structure at the interface, inhibiting the function of LS ( Guzman et al, 2022 ).…”

Synchrotron radiation circular dichroism spectroscopy reveals that gold and silver nanoparticles modify the secondary structure of a lung surfactant protein B analogue

“…[12][13][14][15][16] Similar experiments have also been undertaken using more complete models of pulmonary surfactant for a limited range of nanomaterials and found a deterioration in surface tension behaviour. [17][18][19][20] For example, using the oscillating bubble technique, the effect of bare and coated polymeric NPs on the surface tension behaviour of a phospholipid mixture with and without the addition of different concentrations of SP-B and SP-C, alone and in combination, was investigated. 21 The study found that SP-C supplemented phospholipid mixtures were more susceptible to biophysical inactivation by bare NP than phospholipid mixtures supplemented with SP-B and that effects were reduced for coated particles.…”

Fluid Interfaces as Models for the Study of Lipid-Based Films with Biophysical Relevance

“…In addition, these models may be used to understand how specific chemicals (e.g., contaminants, pharmaceuticals, etc.) modify the structure-function relationship of biomimetic systems [5,[8][9][10][11][12][13][14][15]. However, these model systems are an oversimplification of the complex biophysical framework running in vivo and allow only certain aspects to be mimicked.…”