Fe/Zn composite with high strength-ductility, large-area galvanic corrosion, antibacterial, angiogenic, and osteointegrative capabilities for biodegradable bone-fixation applications

Iron/zinc (Fe/Zn) composite may offer an accelerated degradation rate for bone-implant applications due to the large interfaces between its different constituents. Nevertheless, it is challenging to fabricate a biodegradable composite that exhibits an appropriate aggregation of the mechanical, corrosion, and biological properties required for bone fixation. In this study, we developed an innovative process to fabricate a composite of Fe/Zn via hot extrusion of Zn powder-infiltrated Fe foam for biodegradable bone-fixation applications. This hot-extruded (HE) Fe/Zn sample exhibited the following: ultimate tensile strength 316.3 MPa, tensile yield strength 269.0 MPa, elongation 11.5 %, compressive yield strength 275.3 MPa, and Brinell hardness 77.0 HB, all significantly better than the respective values of its pure Zn counterpart. The HE Fe/Zn also had: electrochemical corrosion rate 2466 μm/a and degradation rate 135.7 μm/a in Hanks' solution. The HE Fe/Zn extract at 12.5 % concentration showed satisfactory cytocompatibility, angiogenicity, osteogenic differentiation, and mineralization capabilities in vitro. The angiogenesis mechanisms of the HE Fe/Zn sample included Jak-STAT and Jak-PI3K-Akt pathways. Furthermore, the HE Fe/Zn sample displayed complete in vivo antibacterial, anti-inflammatory, angiogenic, osteogenic, osteointegration capabilities, and a suitable degradation rate in rat subcutaneous infection and femur defect models.