Dual-sized macro-micro porous biodegradable Zn-Mg-β-TCP scaffolds for bone defect repair: In vitro and in vivo evaluation

Zinc-based materials have been extensively researched as biodegradable bone repair materials in recent years, but their low degradation rate and limited bioactivity need to be further improved. In this study, a new-type dual-sized macro-micro porous Zinc-Magnesium-β-tricalcium phosphate (DMMP Zn-Mg-β-TCP) scaffolds were designed and fabricated by vacuum heating-press sintering. The mechanical properties, degradation behaviors, in vitro biocompatibility, in vivo osteogenesis, and biological safety of the scaffolds were systematically evaluated. The results show that DMMP Zn-Mg-β-TCP has suitable mechanical properties, degradation properties, and excellent osteogenic properties. The compressive yield strength range of the scaffolds is 12.90–25.46 MPa, and the elastic modulus range is 0.31–0.44 GPa, meeting the mechanical properties required for implant materials in cancellous bone. In vitro degradation tests showed that the corrosion rate of the scaffolds ranges from 2.25 to 2.61 mm/y. Furthermore, the scaffolds exhibited excellent in vitro cell compatibility. After a 24-week animal experiment, the scaffold demonstrated excellent osteogenic capacity during bone healing, while maintaining biomechanical stability throughout its degradation process. In summary, the DMMP Zn-Mg-β-TCP has the potential to become a novel biodegradable bone implant material.