Deposition and cellular uptake of Fe3O4 NPs without or with BCs. (A) Representative deposition profile of Fe3O4 NPs without or with BCs based on In Vitro Sedimentation, Deposition, and Dosimetry (ISDD) Modeling over 48 h in a standard 24-well cell culture plate with 500 μL of media present (n = 6/group). (B) Total cellular associated Fe in macrophages cultured in standard 24-well plates with 500 μL of media present. (C) Total Fe remained in media. (D) Total plate associated Fe. Data represent mean + SEM, n = 6/group. *p < 0.05, as compared with the SFM-Fe3O4 NPs group; #p < 0.05, as compared with the FBS-Fe3O4 NPs group.