Aging of Nanoplastics Significantly Affects Protein Corona Composition Thus Enhancing Macrophage Uptake

Nanoplastics (NPs), as emerging contaminants, have attracted
increasing
attention for their effects on human exposure and potential health
risks. The protein corona formed on the surface of NPs affects the
biological activity and fate of the NPs in vivo.
However, how environmental aging, an inevitable process once NPs enter
the environment, affects the formation of protein corona on NPs is
still unclear. This study investigated the changes in the compositions
of protein corona formed on photo-aged polystyrene (PS) NPs in human
bronchoalveolar lavage fluid (BALF), corresponding to the inhalation
exposure pathway. The results demonstrated that both the species and
abundance of proteins in the BALF protein corona on the surface of
PS NPs were altered by aging. In addition, the aged PS NPs are more
hydrophilic and less electronegative than the pristine PS NPs; hence,
there is an increased sorption of more negatively charged hydrophilic
proteins. Moreover, aging-induced alterations in BALF protein corona
enhanced the uptake of aged PS NPs by lung macrophages J774A.1 through
phagocytosis and clathrin-mediated endocytosis. These findings highlight
the importance of environmental aging processes in the biosafety assessment
of nanoplastics.