Fabricating ordered porous β-tricalcium phosphate ceramics having specific structure via the replica method using 3D-CAD-designed polymeric templates

Ordered porous β-tricalcium phosphate (β-TCP) ceramics were fabricated by a replica method using polymer templates each having a diamond lattice, designed with a three-dimensional computer-aided design system. A β-TCP slurry was spray-coated onto these templates and subsequently sintered under optimal conditions determined on the basis of thermogravimetry–differential thermal analysis data. This process allowed accurate transfer of the lattice architecture despite a shrinkage of approximately 65%. Systematic variations of the lattice geometry and coating amount enabled tuning of the porosity, pore size and strut diameter of the ceramic, and compressive testing confirmed the effects of these parameters on the mechanical strength. Structures with interconnected pores having sizes of several hundred micrometers that were well-suited to bone tissue engineering were obtained. X-ray diffraction assessments showed the partial transformation of the β-TCP to an apatite-structured phase during firing while X-ray computed tomography established that prolonged sintering produced hollow struts that provided additional internal space. The replica method combined with specially designed templates was found to be an effective approach to the integrated design of pore architectures that provided suitable mechanical properties and internal space in ordered porous β-TCP scaffolds.