Protein Nanoparticle Charge and Hydrophobicity Govern Protein Corona and Macrophage Uptake

Protein nanoparticles are biomaterials composed entirely of proteins, with the protein sequence and structure determining the nanoparticle physicochemical properties. Upon exposure to physiological or environmental fluids, it is likely that protein nanoparticles, like synthetic nanoparticles, will adsorb proteins and this protein corona will be dependent on the surface properties of the protein nanoparticles. As there is little understanding of this phenomenon for engineered protein nanoparticles, the purpose of this work was to create protein nanoparticles with variable surface hydrophobicity and surface charge and establish the effect of these properties on the mass and composition of the adsorbed corona, using the fetal bovine serum as a model physiological solution. Albumin, cationic albumin, and ovalbumin cross-linked nanoparticles were developed for this investigation and their adsorbed protein coronas were isolated and characterized by gel electrophoresis and nanoliquid chromatography mass spectrometry. Distinct trends in corona mass and composition were identified for protein nanoparticles based on surface charge and surface hydrophobicity. Proteomic analyses revealed unique protein corona patterns and identified distinct proteins that are known to affect nanoparticle clearance in vivo. Further, the protein corona influenced nanoparticle internalization in vitro in a macrophage cell line. Altogether, these results demonstrate the strong effect protein identity and properties have on the corona formed on nanoparticles made from that protein. This work builds the foundation for future study of protein coronas on the wide array of protein nanoparticles used in nanomedicine and environmental applications.