Uptake of nanoparticles by alveolar macrophages is triggered by surfactant protein A

Understanding the bio-nano interactions in the lungs upon the inhalation of nanoparticles is a major challenge in both pulmonary nanomedicine and nanotoxicology. To investigate the effect of pulmonary surfactant protein A (SP-A) on the interaction between nanoparticles and alveolar macrophages, we used magnetite nanoparticles (110-180 nm in diameter) coated with different polymers (starch, carboxymethyldextran, chitosan, poly-maleic-oleic acid, phosphatidylcholine). Cellular binding and uptake of nanoparticles by alveolar macrophages was increased for nanoparticles treated with SP-A, whereas albumin, the prevailing protein in plasma, led to a significant decrease. A significantly different adsorption pattern of SP-A, compared to albumin was found for these five different nanomaterials. This study provides evidence that after inhalation of nanoparticles, a different protein coating and thus different biological behavior may result compared to direct administration to the bloodstream. From the Clinical Editor: In this nano-toxicology study of inhaled nanoparticles, the authors investigated the effect of pulmonary surfactant protein A on the interaction between nanoparticles and alveolar macrophages utilizing magnetite nanoparticles coated with different polymers (starch, carboxymethyldextran, chitosan, poly-maleic-oleic acid, phosphatidylcholine). Cellular binding and uptake of nanoparticles increased for nanoparticles treated with SP-A, whereas albumin, the prevailing protein in plasma, led to a significant decrease. (C) 2011 Elsevier Inc. All rights reserved.