Magnetic resonance imaging of Fe3O4@SiO2-labeled human mesenchymal stem cells in mice at 11.7 T

Fe3O4@SiO2 core-shell nanoparticles were synthesized and used to label human mesenchymal stem cells (hMSCs) for in vitro and in vivo magnetic resonance imaging study. The diameter of the nanoparticles is 24-30 nm with a Fe3O4 core of similar to 8 nm and a SiO2 shell of similar to 8 nm. Transverse relaxivity of the nanoparticles dispersed in water is measured to be similar to 106 mM(-1) s(-1). After incubation with hMSCs for 12 h at a concentration of 100 mu g Fe/mL, cellular uptake of Fe3O4@SiO2 is 20-100 pg Fe/cell, which are located predominantly in the cytoplasm of cells. This level of uptake exhibits no significant influence on hMSCs' viability and differentiation. In vitro imaging of Fe3O4@SiO2-labeled hMSCs evenly distributed in agarose gel yields single cell sensitivity at 11.7 T. In vivo imaging of Fe3O4@SiO2-labeled hMSCs injected into the left brain hemisphere of nude mice yields imaging sensitivity of similar to 130 hMSCs. (C) 2013 Elsevier Ltd. All rights reserved.