Apatite foam fabrication based on hydrothermal reaction of α-tricalcium phosphate foam

Apatite foam (AP foam) is an ideal material for bone substitutes and scaffolds in bone tissue regeneration. This is because its highly porous interconnected pores provide the space for cell growth and tissue penetration, and that its composition induces excellent tissue response and good osteoconductivity. In the present study, the feasibility of apatite foam fabrication was evaluated based on so-called dissolution-reprecipitation reaction of a-tricalcium phosphate (α-TCP) foam granules. When α-TCP foam granules were placed in water at 37°C for 24h, no reaction was observed. However, α-TCP foam set to form AP foam when treated hydrothermally at 200°C The network of fully interconnected pores was retained, and porosity was as high as 82%. Pore size ranged from 50 to 300 μm with average pore size at 160 μm. Compressive strength was 207 kPa. Although no setting reaction was observed at 37°C, setting reaction caused by hydrothermal treatment of α-TCP foam granules at 200°C allows AP foam of any shape to be fabricated. Therefore, this method was suggested to be useful for the fabrication of bone substitutes and the scaffold in bone tissue regeneration.