Development and characterization of titanium-containing hydroxyapatite for medical applications

Abstract

Hydroxyapatite containing levels of titanium (TiHA) of up to 1.6 wt.% has been produced via a chemical co-precipitation route. The distribution of Ti was seen by transmission electron microscopy/energy-dispersive X-ray analysis to be uniform throughout as-prepared nanosized TiHA particles (20nm×100nm). The incorporation of Ti into the HA structure was found to influence the ceramic microstructure on sintering and the grain size was found to decrease from 0.89μm with HA to 0.63μm with 0.8 wt.% TiHA (0.8 TiHA) and 0.45μm with 1.6 wt.% TiHA (1.6 TiHA). Rietveld refinement analysis showed that there was a proportional increase in both the a and c axis with incorporation of Ti into the HA lattice structure, leading to an increase in the cell volume with the addition of Ti. Fourier transform-Raman analysis showed a slight increase in the ratio of O–H/P–O peaks on TiHA, in comparison with HA. A bone-like apatite layer was formed on the surface of TiHA after immersion in simulated body fluid for 3days, which demonstrated the high in vitro bioactivity of TiHA. In vitro culture with primary human osteoblast (HOB) cells revealed that TiHA was able to support the growth and proliferation of HOB cells in vitro, with a significantly higher cell activity being observed on 0.8 TiHA after 7days of culture in comparison with that on HA. Well-organized actin cytoskeletal protein was developed after 1day of culture, and an increase in cell filopodia (attachment) was observed on TiHA sample surfaces. The results indicate that TiHA has great potential for biomedical applications.