Fig. 2

Fe₃O₄ nanoparticle (NP) characterization and internalization by mesenchymal stem cells (MSCs). a TEM images of Fe₃O₄ NPs. Scale bar = 100 nm. b Size distribution of Fe₃O₄ NPs. c MSCs were labeled with Fe₃O₄ NPs (50 μg/mL) for 16 h to determine the optimal labeling efficiency and stained using a Prussian blue iron staining kit. Scale bar = 100 µm. c TEM image of NPs (50 µg/mL) internalized by an MSC. Scale bar = 5 µm. Red arrows indicate NPs observed in the MSC cytoplasm