Fabrication and Properties of Ca-P Bioceramic Spherical Granules with Interconnected Porous Structure

Spherical calcium phosphate (Ca-P) granules show advantages in filling bone cavity defects. In this study, gelatinizing technology combined with microsphere-sintering and gas-foaming methods was applied to fabricate porous spherical Ca-P bioceramic granules. The obtained three kinds of Ca-P granules (i.e., hydroxyapatite, HA-G; biphasic calcium phosphate, BCP-G; and tricalcium phosphate, TCP-G) exhibited uniformly spherical shapes and interconnected pore structures with controlled macropores (about 600 μm), and abundant minor- (10-100 μm) to microsized (<10 μm) pores. The obtained Ca-P granules contained only the HA and β-TCP phases, but their phase ratios (HA/β-TCP) had some changes in the sintering process. All of the Ca-P granules were favorable for serum protein adsorption and bonelike apatite formation, and TCP-G was superior to the other two. Cell-culturing results showed that these Ca-P granules could promote cell adhesion, proliferation, and expression of a series of osteogenic genes. These findings demonstrated that these Ca-P granules had good bioactivity and pro-osteogenic ability, especially for BCP-G and TCP-G. Therefore, the porous spherical Ca-P bioceramic granules fabricated by the novel method show great potential to serve as good candidates for bone defect filling materials.