Fig. 1.

IONPs characterization, cellular uptake of IONPs, and IONPs-SMF triggered cellular modification. (A) Schematic illustration of the preparation of IONP-SMF stimulated exosomes (IONP-Exos) derived from BMSCs that were triggered by IONPs in combination with SMF. (B) Zeta potential spectrum of IONPs dispersed in PBS at room temperature at a concentration of 1 ​mg/mL. (C) Size distribution of IONPs. (D) TEM image of IONPs (20 ​μg/mL) internalized by BMSCs. Red arrows indicate IONPs observed in the BMSC cytoplasm. (E) Compared with normal BMSCs, BMSCs incubated with IONPs (20 ​μg/mL) efficiently internalized IONPs and were stained using a Prussian blue iron staining kit. (F) Cell viability of BMSCs treated with various concentrations of IONPs and measured by CCK-8 assay. (G) Cell viability of BMSCs treated with the optimal concentrations of IONPs combined with different SMF strengths and measured by CCK-8 assay. IONPs: iron oxide nanoparticles; SMF: static magnetic field; TEM: transmission electron microscopy; BMSCs: bone mesenchymal stem cells; CCK-8: Cell Counting Kit-8. Each assay was performed in triplicate and/or carried out in at least three independent experiments; representative results are shown.