An environmental route of exposure affects the formation of nanoparticle coronas in blood plasma

Nanoparticles (NPs) in contact with biological fluids become covered by a tightly bound layer of proteins, the "protein corona", giving a new biological identity to NPs as the cell machinery can engage with the coated surface differently than with the bare one. We here consider the scenario that exposure to nanoparticles occurs through an environmental route, exemplified by using hydrophobins, fungal proteins that are highly adhesive and secreted into the environment in large quantities by fungi. The highly secreted hydrophobin, HFBII of Trichoderma reesei is used as a model. In this work we have used a strategy to coat and characterize nanoparticles of different size and surface modification. Hydrophobin coated nanoparticles of varying size and surface modification are shown to strongly increase stability and dispersion of the NPs in human plasma compared to pristine particles. It is also shown that the presence of hydrophobin on the NPs results in a decrease of layer thickness and a change in composition of the protein corona, and that the hydrophobin remained strongly associated to the NPs in competition with plasma proteins. As a conclusion we therefore suggest that the route of exposure of nanoparticles strongly affect their surface properties and possible physiological behavior.