The effect of salts in aqueous media on the formation of the BSA corona on SiO2 nanoparticles.

Protein-nanoparticle interactions are garnering attention due to their potential impacts on human health and environmental contamination. The colloidal properties of nanoparticles (NPs) in aqueous media may differ in the presence of natural materials such as salts and proteins. In this study, the interactions between bovine serum albumin (BSA) and fumed hydrophilic silicon dioxide (SiO2) NPs were studied in aqueous solutions under variable pH or ion composition. Investigation of hydrodynamic diameter and zeta potential changes to nanoparticles upon addition of BSA, the adsorption of BSA to the SiO2 NP surface, and the interaction energy between particles revealed that buffered solutions promote protein adsorption onto NPs and particle agglomeration. The effects of ionic salt solutions were dependent on the ion charge, with negatively charged ions stabilizing the system and positively charged ions promoting protein-nanoparticle interactions. These data highlight that physiologically relevant salts affect protein corona formation on non-toxic, amorphous SiO2 NPs and spur the need for well-defined characterization conditions when determining potential toxicity of NPs upon human or animal exposure.