Titanium-nanohydroxyapatite composites produced by ball milling and sintering: wettability, bioactivity and toxicity studies

In the present work, nano-hydroxyapatite (HA) was used as dispersing phase to develop Ti based composites. The mixture of powders with 5% and 10% HA and remaining being Ti were ball milled for 20 h. The ball milled powders were characterized by X-Ray diffraction analysis, electron microscopy. The powders were then sintered at 850 °C in vacuum. Higher surface energies were observed for the composites compared with medical grade purer Ti calculated from the water contact angles. This can be attributed to the smaller grain size and the presence of nano-HA in the composites. Immersion studies carried out in simulated body fluid for 4 weeks demonstrated excellent bioactivity for the composite as reflected from the higher mineral deposition from the SBF. This can be explained by considering the effect of higher wettability and added nano-HA in the composites. All the samples were found to be nontoxic against 3T3 cells as observed from the cytotoxicity test using MTT assay. Hence, from the results, it can be understood that bioactive Ti-HA composites can be produced from ball milling and sintering which exhibit excellent bioactivity to promote higher healing rate.