Microstructure, mechanical properties, in vitro degradation behavior and cytocompatibility of biodegradable Zn-3Fe-HAP composites prepared by vacuum heating-press sintering

Abstract

Zinc (Zn) is a promising biodegradable material, and have attracted widespread attention due to its befitting degradation rate compared to magnesium (Mg) and iron (Fe). However, the inferior mechanical strength of pure Zn limits its application for bone repair. Therefore, there is an urgent need to improve its mechanical properties, regulate its degradation rate, and endow it with optimal biocompatibility. The alloying of metallic elements and preparation of Zn-based composites can be a promising approach for this purpose. In this study, the pure Zn and Zn-3 wt%Fe-xHAP (x = 0, 5, 10, 15, 20 wt%) samples were fabricated by vacuum heating-press sintering. The microstructure, compressive mechanical property, in vitro degradation behavior, antibacterial property and in vitro cytocompatibility of different samples were investigated. We confirmed that the secondary phase Zn13Fe significantly improved the mechanical property, and micro-galvanic between Zn and Fe accelerated degradation of the samples. Compressive yield strength of all samples ranges from 85.65 MPa to 301.99 MPa, compressive elastic modulus varies between 8.26 GPa and 15.03 GPa, and corrosion rates are significantly improved which are about 0.005–3.065 mm/y. Moreover, Zn-3Fe-xHAP samples exhibited better biocompatibility and antibacterial property than pure Zn, especially the sample of Zn-3Fe-5HAP. In summary, biodegradable Zn-based composites prepared by vacuum heating-press sintering could be promising material for bone repair.