Fabrication and characterization of ZnO/HA scaffolds via spark plasma sintering at different temperatures for bone repair.

Hydroxyapatite (HA) has good biocompatibility and biological activity which can be widely used in bone defect repair. Zinc oxide nanoparticles (ZnO NPs) can promote osteogenesis by enhancing angiogenesis and exhibit notable antibacterial properties. Sintering temperatures critically influence the physicochemical and biological properties of bioceramic scaffolds. In this study, porous ZnO/HA bioceramic scaffolds were fabricated at various sintering temperatures, and their structural, mechanical, and biological properties were systematically investigated. The results demonstrated that increasing sintering temperature led to reduced porosity and degradation rate, accompanied by a significant improvement in compressive strength. Biocompatibility remained consistently high across all temperatures, with all scaffolds exhibiting excellent cell compatibility and osteogenic ability. However, antibacterial efficacy declined with increasing temperature. Notably, bioceramic scaffolds sintered at 950 °C achieved an optimal balance of porosity, mechanical strength, and osteogenic potential, making them promising candidates for repairing critical-sized bone defects.