Development of bioactive materials based on bone-bonding mechanism on metal oxides

Abstract

Bioactive ceramics have high biological affinity that enables direct bone-bonding. However they do not have mechanical performances enough to repair bone tissue under loaded conditions. It has been revealed that most materials exhibiting bioactivity form bone-like apatite in body environment. We investigated apatite-forming ability of tantalum- and niobium-based oxide gels in simulated body environment in order to fundamentally clarify chemical structure effective for achieving bioactivity. We found that Ta-OH and Nb-OH groups on the surfaces of the oxide gels have a potential to form the apatite. On the basis of these findings, we have successfully provided tough tantalum metal with bioactivity by simple NaOH and heat treatments that form a lot of Ta-OH groups on their surfaces. We also synthesized bioactive organic-inorganic hybrids with flexibility by organic modification of inorganic chemical species with apatite-forming ability. A sequence of material design described above would produce bioactive materials with various mechanical properties.