Preparation and evaluation of magnetic nanoparticles for cell labeling.

Cell labeling and tracking are becoming increasingly important in the fields of stem cell transplantation. To track the migration and distribution of the implanted cells is critical for understanding the beneficial effects of stem cell therapy. The aim of this study is to synthesize new superparamagnetic nanoparticles and investigate the feasibility of magnetic labeling of bone marrow mesenchymal stem cells (MSCs). Monodisperse hydrophobic magnetite (Fe3O4) nanoparticles were prepared through high temperature decomposition of Fe(acac)3 and a long-chain alcohol. The nanoparticles were further modified with a bipolar surfactant, 2,3-dimercaptosuccinic acid (DMSA) and then transformed into water-soluble iron oxide nanoparticles (WION). The magnetic particles showed uniform size (10 nm), high efficiency and stability in MSCs labeling. The labeled cells were cultured until passage 8, there is no reduction in magnetic tropism and the percentage of labeled cells. The results of MTT proliferation assay and flow cytometry analysis show that the WION are biocompatible. The labeling process does not cause cell death and apoptosis, and has no side effect on growth capacity of the cells. In conclusion, the successful and stable labeling of MSCs and the efficient magnetic tropism indicate that this WION can be used for tracking of MSCs in future MSCs-based stem cell therapy.