Dextran-coated fluorapatite nanorods doped with lanthanides in labelling and directing osteogenic differentiation of bone marrow mesenchymal stem cells.

Terbium (Tb) or europium (Eu)-doped fluorapatite nanorods (Tb/Eu-FHA) were prepared using a hydrothermal method. The structure, morphology, and luminescence of the products were determined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and photoluminescence spectra (PL). The surfaces of the Tb/Eu-FHA nanorods were further conjugated with hydrophilic cationic polymers, such as dextran, to enhance hydrophilicity, biocompatibility and cell penetration. Then, the dextran-coated nanorods were cocultured with bone marrow mesenchymal stem cells (BMSCs). A luminescence signal in the cells was detected after 12 hours with a laser scanning confocal microscope (LSCM). Labelled BMSCs were shown to reproducibly exhibit osteogenic differentiation potential in real-time PCR and ELISA assays. In vivo cell-tracking experiments also suggested that dextran-coated Tb-FHA nanorods could be used as a stable tracer of BMSCs. Therefore, dextran-coated Tb-FHA nanorods can be utilised for tracking and monitoring BMSCs in vitro and in vivo. Our current work attempts to provide an excellent fluorescent cell labelling agent for BMSCs in bone tissue engineering.