Synthesis, characterization and cytocompatibility of ZrO2 doped borosilicate bioglasses

Glasses with the composition of 31B2O3-20SiO2-24.5Na2O-(24.5-x)CaO-xZrO2 by varying zirconia content (x = 0, 1, 3, 5) were synthesized via conventional melt-quenching technique. The in-vitro properties of these glasses such as bioactivity, cytocompatibility are described in the present report. In-vitro bioactivity of these glasses was analyzed for various immersion timings by means of X-ray diffraction, Fourier transform infrared (FTIR) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Cytocompatibility was assessed by MTT assay with human osteosarcoma cells (MG-63). Micro hardness values of the prepared glasses have been measured with Vickers hardness tester. From the present study, it is observed that micro hardness of the glass samples increased from 5.45 GPa to 6.17 GPa with increasing ZrO2 content and it is also observed that the formation of hydroxyapatite layer on the surfaces of the glasses within 5 days of immersion time. With increasing immersion time, intense hydroxyapatite layer formation on the surface of glasses is observed. Increasing the zirconia content in the glass samples results in increase in hardness and decrease in in-vitro bioactivity. It is also observed that cell viability is not affected by the addition of zirconia.