The selection of scaffold materials and the optimization of scaffold morphological and mechanical properties are critical for successful bone tissue engineering. We fabricated porous scaffolds of nano-sized zirconia using a replication technique. The study aimed to explore the relationship between porosity, pore size, mechanical strength, cell adhesion, and cell proliferation in the zirconia scaffolds. Macro- and micro-structures and compressive strength were comparatively tested. Beagle bone marrow stromal cells were seeded onto the scaffolds to evaluate cell seeding efficiency and cell proliferation profile over 14 d of incubation. The zirconia scaffolds presented a complex porous structure with good interconnectivity of pores. By increasing the sinter cycles, the porosity and pore size of the scaffolds decreased, with mean values ranging from 92.7-68.0% and 830-577 μm, respectively, accompanied by increased compressive strengths of 0.6-4.4 MPa. Cell seeding efficiency and cell proliferation over the first 7 d of incubation increased when the porosity decreased, with cell viability highest in the scaffold with a porosity of 75.2%. After 7 d of incubation, the cell proliferation increased when the porosity increased, highest in the scaffolds with a porosity of 92.7%. These results showed that the zirconia scaffold with a porosity of 75.2% possesses favorable mechanical and biological properties for future applications in bone tissue engineering.

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