Modulation of Osteogenesis and Angiogenesis Activities Based on Ionic Release from Zn–Mg Alloys

Abstract

The enhancement of osteogenesis and angiogenesis remains a great challenge for the successful regeneration of engineered tissue. Biodegradable Mg and Zn alloys have received increasing interest as potential biodegradable metallic materials, partially due to the biological functions of Mg2+ and Zn2+ with regard to osteogenesis and angiogenesis, respectively. In the present study, novel biodegradable Zn–xMg (x = 0.2, 0.5, 1.0 wt.%) alloys were designed and fabricated, and the effects of adding different amounts of Mg to the Zn matrix were investigated. The osteogenesis and angiogenesis beneficial effects of Zn2+ and Mg2+ release during the biodegradation were characterized, demonstrating coordination with the bone regeneration process in a dose-dependent manner. The results show that increased Mg content leads to a higher amount of released Mg2+ while decreasing the Zn2+ concentration in the extract. The osteogenesis of pre-osteoblasts was promoted in Zn–0.5Mg and Zn–1Mg due to the higher concentration of Mg2+. Moreover, pure Zn extract presented the highest activity in angiogenesis, owing to the highest concentration of Zn2+ release (6.415 μg/mL); the proliferation of osteoblast cells was, however, inhibited under such a high Zn2+ concentration. Although the concentration of Zn ion was decreased in Zn–0.5Mg and Zn–1Mg compared with pure Zn, the angiogenesis was not influenced when the concentration of Mg in the extract was sufficiently increased. Hence, Mg2+ and Zn2+ in Zn–Mg alloys show a dual modulation effect. The Zn–0.5Mg alloy was indicated to be a promising implant candidate due to demonstrating the appropriate activity in regulating osteogenesis and angiogenesis. The present work evaluates the effect of the Mg content in Zn-based alloys on biological activities, and the results provide guidance regarding the Zn–Mg composition in designs for orthopedic application.