Biological properties of Zn–0.04Mg–2Ag: a new degradable zinc alloy scaffold for repairing large-scale bone defects

Treatment of large-scale bone defects remains a clinical challenge. In particular, it preferably requires an implantable material with porous, absorbable, biocompatible, and antibacterial activities. Here we report the mechanical and biological properties of a porous Zn–0.04Mg–2Ag (wt%) biodegradable zinc alloy scaffold, prepared by template replication technique. In the aspect of cytocompatibility, cytoskeleton staining of stem cells co-cultured with Zn–0.04Mg–2Ag showed that the outline of cells and nuclei was clearly visible, and the interwoven network of linear fibers was abundant in the cells, which revealed lower cytotoxicity and less effect on cell proliferation. In the aspect of antibacterial properties, Zn–0.04Mg–2Ag alloy had little antibacterial effect on Escherichia coli, but had obvious antibacterial ability against Staphylococcus aureus and Staphylococcus epidermidis. In the aspect of bone induction, alizarin red staining and the expression of alkaline phosphatase showed no obvious increase; However, Zn–0.04Mg–2Ag alloy could significantly up-regulate the mRNA expression of osteoblast-specific transcription factors, osteocalcin and osteopontin. Zn–0.04Mg–2Ag degradable zinc alloy scaffold had excellent biocompatibility, and has significant antibacterial activity and fine osteogenic induction, which was an ideal bone substitute material for repairing large-scale bone defects.