Physical and biocompatibility studies of novel titanium dioxide doped phosphate-based glasses for bone tissue engineering applications

This study investigated doping titanium dioxide (TiO2) into phosphate glasses, 50 P2O5-30 CaO-20 Na2O, to control their degradation rate and enhance their biological response to be suitable scaffolds for bone tissue engineering applications. The thermal and structural properties were analysed using differential thermal analysis and X-ray powder diffraction. The effect of TiO2 incorporation on degradation rate, ion release, and pH changes was also carried out. In vitro cyto-biocompatibility was assessed through MG63 human osteosarcoma cells attachment and viability using scanning electron microscopy and confocal microscopy, respectively. The results showed that addition of TiO2 produced a significant increase in density and glass transition temperature. X-ray diffraction analysis showed the presence of NaCa(PO3)(3) as a main phase of these glasses with titanium phosphate Ti-P2O7 only detected for 5 mol% TiO2 glasses. The degradation rate, however, was significantly reduced by one order of magnitude with incorporation of 5 mol% TiO2 which has been reflected in released ions (cations and anions) and the minimal pH changes. Moreover, addition of TiO2, 3 and 5 mol% in particular, supported the MG63 cells attachment and maintained high cell viability up to 7 days culture comparable to Thermanox (R). These results suggested that TiO2 containing phosphate glasses can be a promising substrate for bone tissue engineering applications.