In this study,we investigated the in vivo behaviors of chiral cobalt oxide nanoparticles (Co3O4 NPs) stabilized with D-or L-cysteine(denoted D-or L-NPs,respectively),as representative chiral metal oxide NPs.Chiral Co3O4 NPs exerted no observable cytotoxicity within the tested dose range.Both D-NPs and L-NPs were internalized by dendritic cells through caveola-dependent endocytosis,and L-NPs entered the cells faster than D-NPs.Significantly,a metabolic analysis indicated that chiral L-NPs had the same effect on the level of bile acids in the liver as D-NPs,which is attributed to the almost equal amount of farnesoid X receptor (FXR) induced by the chiral NPs.This study suggests that low chiroptical activity nanomaterials would not affect the metabolism and kinetics under physiological conditions even if there is some difference in their transport.