Synthesis of hierarchical and flower-like TiO2 nanowire microspheres as biocompatible cell carriers

Fibrous materials are of great interest in the development of tissue regenerative matrix. However, synthesis of inorganic fibrous microspheres as cell carriers is a great challenge. In this study, we for the first time report on the synthesis of novel hierarchical and flower-like TiO2 nanowire (NW) microspheres as biocompatible cell carriers. TiO2 NW microspheres were synthesized through in situ alkali hydrothermal treatment of the TiO2 nanoparticle (NP) microspheres and their microstructure, formation mechanism and in vitro biocompatibility were evaluated. SEM observations show that the resulting TiO2 NW microspheres were constructed by a large number of NWs with the diameter of 10-20 nm and exhibited a flower-like and hierarchical morphology with the diameter of 400-600 mu m. XRD patterns indicate that TiO2 NW microspheres were constructed by both rutile and anatase phase of TiO2. FT-IR spectra reveal that Ti-O-Ti bonds were involved in TiO2 NW microspheres. In vitro biocompatibility was evaluated by seeding the fibroblast L929 cells on the microspheres. A conventional MTT assay quantitatively indicates that the TiO2 NW microspheres favored adhesion and proliferation of cells and were biocompatible, while SEM observations qualitatively confirmed that the cells were well grown on the surface of TiO2 NW microspheres. Thus, the as-synthesized TiO2 NW microspheres would be applicable to novel and biocompatible cell carriers.