Biophysicochemical interaction of a clinical pulmonary surfactant with nano-alumina

TL;DR

This study investigates how pulmonary surfactant interacts with nanometric alumina particles, revealing electrostatic complexation and aggregate formation that could influence nanotoxicity in lungs.

Contribution

It provides new insights into the biophysical interactions between clinical surfactant and alumina nanoparticles, highlighting aggregate formation and structural integrity of vesicles.

Findings

Micron-sized aggregates form at critical stoichiometry.

Vesicles retain their structure and trap particles.

Agglomeration may affect particle interactions with lung cells.

Abstract

We report on the interaction of pulmonary surfactant composed of phospholipids and proteins with nanometric alumina (Al2O3) in the context of lung exposure and nanotoxicity. We study the bulk properties of phospholipid/nanoparticle dispersions and determine the nature of their interactions. The clinical surfactant Curosurf, both native and extruded, and a protein-free surfactant are investigated. The phase behavior of mixed surfactant/particle dispersions was determined by optical and electron microscopy, light scattering and zeta potential measurements. It exhibits broad similarities with that of strongly interacting nanosystems such as polymers, proteins or particles, and supports the hypothesis of electrostatic complexation. At a critical stoichiometry, micron sized aggregates arising from the association between oppositely charged vesicles and nanoparticles are formed. Contrary to the models of lipoprotein corona or of particle wrapping, our work shows that vesicles maintain their structural integrity and trap the particles at their surfaces. The agglomeration of particles in surfactant phase is a phenomenon of importance since it could change the interactions of the particles with lung cells.