Nonspherical Silica Nanoparticle Aggregates Exacerbate Pulmonary Surfactant Monolayer Disturbance

To enhance understanding of the biotoxicity of inhaled lunar dust (LD) and safeguard astronaut health during future crewed lunar missions, we performed coarse-grained molecular dynamics simulations of nine silica nanoparticle (SiNP) aggregates─the primary component of LD─varying in size (3 and 6 nm), shape (sphere, ellipsoid, and cube), and surface features (0, 1, and 3 bulges) interacting with a pulmonary surfactant (PS) monolayer. The key findings are (1) shape, not size, governs aggregate architecture and fate: cubic SiNPs yield the most aspherical, rapidly forming aggregates and switch translocation from penetration to embedding when present as 6 nm members, and aggregation time scales as cube > ellipsoid > sphere. (2) Aggregates induce greater PS disturbance than equal-volume single SiNP, and the DPPC order parameter S_z falls to 0.678-0.706 and is driven lower (0.587-0.720) when nonspherical SiNPs dominate the aggregates. (3) Surface bulges normally hinder translocation, yet once their size and number exceed a threshold, they locally rupture the PS monolayer and shorten translocation while still increasing PS adsorption and S_z. These findings establish that aggregate morphology, rather than mass, exacerbates PS monolayer disturbance and provide quantitative benchmarks for guiding dust-mitigation strategies for future lunar missions.