Research on corrosion behavior and biocompatibility of a porous Mg–3%Zn/5%β-Ca3(PO4)2 composite scaffold for bone tissue engineering

Background: Rapid corrosion rates are a major impediment to the use of magnesium alloys in bone tissue engineering despite their good mechanical properties and biodegradability. Zinc is a promising alloy element, and it is an effective grain refiner for magnesium. β-Ca3(PO4)2 (β-TCP) is widely used for bone regeneration because of its good biocompatibility, and it also has a similar chemical and crystal structure to human bone. Methods: In this research, the magnesium alloy was reinforced by adding 3%Zn (wt.%) and 5%β-TCP (wt.%) particles in order to improve the corrosion resistance and biocompatibility. Furthermore, the biomaterial was prepared through powder metallurgy technology using NH4HCO3 as space-holding particles to construct porous Mg–3%Zn/5%β-TCP scaffolds. Results: The results revealed that the magnesium-zinc phase and calcium phosphate phase were uniformly distributed in the α-magnesium matrix. Mechanical and corrosion tests indicated that the scaffolds had mechanical strengths similar to that of human bone, and their corrosion resistance decreased with an increase in the porosity. The scaffolds had cytotoxicity grades of 0–1 against MG63 cells, SaoS2 cells, and HK-2 cells, which suggested that they were appropriate for cellular applications. In addition, the scaffolds demonstrated excellent biocompatibility when tested in rabbits. Conclusions: These results indicate that porous Mg–3%Zn/5%β-TCP scaffolds are promising biodegradable implants for bone tissue engineering.