The Bioactive Mg-Zn-Gd Wire Enhances Musculoskeletal Regeneration: An In Vitro Study

Abstract

Magnesium (Mg)-based implants were extensively developed and tested to improve the shortages of traditional hard metal implants. Unlike the nail, screw, and plate, pure Mg wire is rarely applied in the musculoskeletal system because of its poor mechanical properties. Therefore, we developed the magnesium–zinc–gadolinium (ZG21) alloy wire, which presented good mechanical properties. Before the in vivo study, the in vitro tests were carried out in this study. The ZG21 wire was scanned by SEM/EDS. The changing rate of weight and pH values were recorded during degradation. The corrosion interface was scanned by SEM/EDS. The cytotoxicity of metal extracts, Mg, Zn, and Gd ions was tested. The osteogenic and angiogenic potential was also evaluated. The ZG21 wire degraded at a stable speed in 14 days. The extracts were diluted ten times, and the correspondent ion concentration presented low cytotoxicity for cell lines of pre-osteoblasts, fibroblasts, and endothelial vessel cells. Pre-osteoblast cell lines cultured with 10% extracts presented significantly higher osteogenic potential. Endothelial vessel cell lines cultured with 2.5, 5, and 10 mM Mg2+ presented significantly higher angiogenic potential. The ZG21 wire could maintain an intact structure when making a surgical knot. Its degradation process and products presented low toxicity and potential for osteogenesis and angiogenesis. The ZG21 wire could be identified as a safe and bioactive material for further in vivo musculoskeletal regeneration.