Synthesis of functional gradient BCP/ZrO2 bone substitutes using ZrO2 and BCP nanopowders

BCP/BCP–ZrO2/ZrO2 scaffold with a functionally gradient layered structure (FG BCP/ZrO2) was fabricated by the polymeric sponge replica method and subsequent dipping process. To enhance the compressive strength and bioactive properties of monolithic ZrO2 scaffold, ZrO2 and BCP phases were selected as a main frame and surface layer, respectively. The formation of microcracks was significantly decreased by incorporating an intermediate layer consisting of BCP–ZrO2 phase. The thicknesses of the monolithic ZrO2, BCP–ZrO2, and BCP layer were around 10–30 μm, 3–5 μm, and 2–3 μm, respectively. The FG BCP/ZrO2 scaffold showed highly interconnected pores as well as good material properties, which were 68% porosity and 7.2 MPa of compressive strength. Average pore size of FG BCP/ZrO2 scaffold was about 220 μm in diameter. From MTT assay and SEM observation of osteoblast-like MG-63 cells, FG BCP/ZrO2 scaffold showed good cell viability and faster proliferation behavior.