Fabrication of β-tricalcium phosphate composite ceramic spherebased scaffolds with hierarchical pore structure for boneregeneration

摘要

Polymer sphere-based scaffolds, which are prepared by bonding the adjacent spheres via sintering therandomly packed spheres, feature uniform pore structure, full three-dimensional (3D) interconnection, and considerable mechanical strength. However, bioceramic sphere-based scaffolds fabricatedby this method have never been reported. Due to high melting temperature of bioceramic, onlylimited diffusion rate can be achieved when sintering the bioceramic spheres, which is far from enoughto form robust bonding between spheres. In the present study, for the first time we fabricated 3Dinterconnected β-tricalcium phosphate ceramic sphere-based (PG/TCP)scaffolds by introducingphosphate-based glass(PG) as sintering additive and placing uniaxial pressure during the sinteringprocess. The sintering mechanism of PG/TCP scaffolds was unveiled. The PG/TCP scaffolds hadhierarchical pore structure, which was composed by interconnected macropores(>200 μm) amongspheres, pores(20–120 μm)in the interior of spheres, and micropores(1–3 μm) among the grains.During the sintering process, partial PG reacted with β-TCP, forming β-Ca2P2O7; metal ions from PGsubstituted to Ca2+ sites of β-TCP. The mechanical properties(compressive strength 2.8–10.6 MPa;compressive modulus 190–620 MPa) and porosity (30%–50%) of scaffolds could be tailored bymanipulating the sintering temperatures. The introduction of PG accelerated in vitro degradation ofscaffolds, and the PG/TCP scaffolds showed good cytocompatibility. This work may offer a newstrategy to prepare bioceramic scaffolds with satisfactory physicochemical properties for applicationin bone regeneration.