Sintering Behavior and Biocompatibility of Calcium Phosphates Fabricated by Cuttlefish Bone and Phosphoric Acid

Biocompatible and dense calcium phosphates, hydroxyapatite (HAp) and beta-tricalcium phosphate (beta-TCP) were successfully fabricated by using recycled cuttlefish bone. Calcined cuttlefish bone (CCB) and phosphoric acid (PA) were mixed homogeneously in different proportions, dried and the resultant powders were calcined at various temperatures. The HAp and beta-TCP were stably formed at about 900 degrees C for CCB:PA of 1:1.1 wt% and 1:1.4 wt%, respectively. The powder compacts were prepared and were fully densified under optimal sintering conditions. The in-vitro cytotoxicity, including cell attachment and proliferation of the sintered HAp disks, was examined using human, bone marrow-derived, multipotent, stem cells (hBMSCs). Cell response was characterized by MTT assay, alkaline phosphatase stain and RT-PCR analysis. The adhesion of hBMSCs to the synthesized HAp disk surface was found to be similar to that prepared from commercial HAp. In addition, the synthesized HAp disk did not exhibit any cytotoxicity towards the hBMSCs undergoing osteoblastic differentiation. The hBMSCs adhering to the synthesized HAp or to the commercial HAp disk displayed undistinguishable actin arrangements and cellular phenotypes. This suggests that the synthesized calcium phosphate does not disrupt normal cellular responses.