A Simulation Study on the Interaction Between Pollutant Nanoparticles and the Pulmonary Surfactant Monolayer

Area of Science:

• Environmental Science
• Materials Science
• Biophysics

Background:

• Inhaled pollutant nanoparticles (NPs) pose risks to human health.
• Pulmonary surfactant monolayers are crucial for lung function and interact with airborne particles.

Purpose of the Study:

• To investigate the interaction mechanisms between various NPs and pulmonary surfactant monolayers.
• To analyze how NP properties and breathing states affect NP translocation across the surfactant layer.

Main Methods:

• Coarse-grained molecular dynamics simulations were employed.
• Models of four representative NPs (CaSO4, C, SiO2, C6H14O2) and a pulmonary surfactant monolayer were established.
• Simulations covered exhalation and inhalation breathing states, analyzing potential energy, NP displacement, orderliness, and surface tension.

Main Results:

• NPs inhibit the surfactant monolayer's surface tension regulation.
• Hydrophobic NPs (C) showed limited translocation and significant monolayer disruption.
• Highly hydrophilic NPs (SiO2, C6H14O2) translocated easily with minimal impact.
• Semi-hydrophilic NPs (CaSO4) translocated only during inhalation.
• Flaky NPs exhibited superior penetration compared to rod-shaped and spherical NPs.
• Increased cholesterol in the monolayer hindered NP translocation.

Conclusions:

• NP hydrophilicity and structure significantly dictate their interaction with pulmonary surfactant.
• Breathing state dynamics influence NP penetration capabilities.
• Cholesterol content modulates surfactant monolayer properties, affecting NP permeability.