Fabrication and characterization of biodegradable Mg-Zn-Y-Nd-Ag alloy: Microstructure, mechanical properties, corrosion behavior and antibacterial activities

Abstract

Magnesium (Mg), a potential biodegradable material, has drawn wide attention in the bone reconstruction field. However, Mg alloys, served as the bone graft substitution, remain a clinical challenge, the antibacterial activity of which is required to be enhanced. Here, we prepared biodegradable magnesium Mg-Zn-Y-Nd-Ag and then had it been further densified by extruding. The microstructure evolution of the as-cast and as-extruded Mg- Zn-Y-Nd-Ag was characterized using optical microscope and X-ray diffraction analyses (XRD). The results showed that the microstructure of the as-cast alloys was mainly dendrites, between which, the second phase was mainly distributed; with the increase of Ag additions, grain structure was further refined as well as the increase of amount of the second phase. After the extrusion, the grains were further refined. Microhardness tests indicated that both of the increase of Ag content and the extrusion process improved the microhardness of the alloys, specially the later. A systematic investigation of the in vivo antibacterial capability of Staphylococcus aurous and Escherichia coli was performed, and the results of which indicated that all Mg-Zn-Y-N-xAg (x = 0.2, 0.4, 0.6, 0.8) alloys exhibited certain antibacterial property, which would increased with the increase of Ag content. Taken all together, the antimicrobial property of the as-extruded alloy containing 0.4 wt% Ag exhibited the relatively better antimicrobial properties and mechanical property with the relatively small loss in corrosion resistance, which suggested the potential utility of as-extruded Mg-Zn-Y-N-0.4Ag in treating orthopedic infections.

Recent Advances in Research on Antibacterial Metals and Alloys as Implant Materials

“…This antibacterial effect has been attributed to the microstructure of the alloy and the Ag content (Liu et al, 2017). Similarly, the addition of 4 wt% Ag to the extruded Mg-Zn-Y-Nd alloy showed good antibacterial activities, mechanical properties, and corrosion resistance (Feng et al, 2018).…”

Advances in coatings on magnesium alloys for cardiovascular stents – A review

“…1 ) [ 37 , 57 , 58 ]. According to application requirements, a large number of Mg alloys with excellent performance that is suitable for vascular stents have been designed, including AE21 alloy [ 59 ], WE43 alloy [ 60 , 61 ], AZ91 alloy [ 62 ], Mg-Nd-Zn-Zr alloy (JDBM) [ 63 , 64 ], and Mg-Zn-Y-Nd alloy (ZE21B) [ 65 , 66 ]. However, the amount of alloy elements required is larger, and the cost is higher.…”

Amorphous and Crystalline Magnesium Alloys for Biomedical Applications

“…There is no information in the literature on the influence of Au and Pt addition on the degradation rate and mechanical properties of magnesium alloys. There are several sources for adding silver to magnesium alloys [41,42].…”