Biodegradable metal-derived magnesium and sodium enhances bone regeneration by angiogenesis aided osteogenesis and regulated biological apatite formation

Biodegradable metals have great attraction to become orthopaedic implants. Here, we demonstrated a biodegradable magnesium alloy incorporated with essential element sodium through Sn-Na master alloying technique. The designed MgSnZnNa alloy presented better hardness and corrosion resistance due to the uniform distribution of Na in Mg₂Sn second phase and solid soluble Zn in Mg matrix. The co-release of Mg and Na ions resulted in advanced upregulation of osterix and osteocalcin expression in adipose derived stem cells in vitro. It significantly promoted the rat calvarial defect bone regeneration through osteogenesis and angiogenesis, attributed to the co-release of Na and Mg ions, by increasing the expression of calcitonin gene-related peptide, osteocalcin as well as vascular endothelial growth factor. The current study provided an innovative approach by using master alloy to incorporate essential elements (such as Na or K) for fabricating biodegradable Mg alloys with reduced galvanic corrosion and enhanced biological functions.