Design of bioactive bone substitutes based on biomineralization process

A material able to form bone-like apatite on its surface in the living body bonds to living bone through the apatite layer. Functional groups such as Si-OH, Ti-OH, Zr-OH, Nb-OH and Ta-OH induce apatite formation in the living body. On the basis of these findings, various kinds of bioactive materials with different mechanical properties can be designed. For example, bioactive titanium metal, its alloys and tantalum metal can be obtained by forming a thin sodium titanate or tantalate layer on their surfaces by NaOH solution and heat treatments. ive organic polymers can be obtained by forming a thin CaO–SiO2 or TiO2 layer on their surfaces by a sol–gel method. These bioactive materials are believed to be useful as unique bone substitutes.