Microstructure, mechanical properties, in vitro degradation behavior and in vivo osteogenic activities of Zn-1Mg-β-TCP composites for bone defect repair

Abstract

Repair of bone defects remains a major challenge in the field of orthopedics. Biodegradable zinc (Zn) has been considered as a revolutionary material for bone repair. However, it exhibits relatively poor mechanical strength and cytocompatibility as well as slow degradation rate, hindering its potential application as bone repair material. In the present work, biodegradable Zn-1 wt%Mg-nvol%β-TCP (n = 0, 1, 3, 5, 10) composites are fabricated via vacuum heating-press sintering to address the above concerns. The results show that the addition of magnesium (Mg) and beta-tricalcium phosphate (β-TCP) positively regulate the mechanical properties, degradation properties, and osteogenic activity of the composites. Zn-1 wt%Mg-3 vol%β-TCP possess the highest compressive yield strength of approximately 243.9 MPa compared with about 137.6 MPa of pure Zn. The in vitro corrosion rates of the Zn-1Mg-β-TCP composites are tunable between 0.428 and 0.546 mm/y. The 24-week in vivo experiments prove that the Zn-1Mg-β-TCP composites possess better osteogenic activity than that of pure Zn. In general, the Zn-1Mg-β-TCP composites exhibit suitable mechanical strength and degradation rate, coupled with their great biological activity, which are expected to provide reliable performance for clinical bone repair.