Interaction with the pulmonary surfactant film, being the first line of host defense, represents the initial bio-nano interaction in the lungs. Such interaction determines the fate of the inhaled nanoparticles and their potential therapeutic or toxicological effect. Despite considerable progress in optimizing physicochemical properties of nanoparticles for improved delivery and targeting, the mechanisms by which inhaled nanoparticles interact with the pulmonary surfactant film are still largely unknown. Here, using combined in vitro and in silico methods, we show how hydrophobicity and surface charge of nanoparticles differentially regulate the translocation and interaction with the pulmonary surfactant film. While hydrophilic nanoparticles generally translocate quickly across the pulmonary surfactant film, a significant portion of hydrophobic nanoparticles are trapped by the surfactant film and encapsulated in lipid protrusions upon film compression. Our results support a novel model of pulmonary surfactant lipoprotein corona associated with inhaled nanoparticles of different physicochemical properties. Our data suggest that the study of pulmonary nanotoxicology and nanoparticle-based pulmonary drug delivery should consider this lipoprotein corona. [http://dx.doi.org/10.1021/nn4054683] The article was published as: Hu GQ,Jiao B,Shi XH, Valle RP,Fan QH,Zuo YY. Physicochemical properties of nanoparticles regulate translocation across pulmonary surfactant monolayer and formation of lipoprotein corona. ACS NANO, 2013, 7(12):10525-10533, doi: 10.1021/nn4054683