A biodegradable Zn-Se alloy with potent osteogenicity, antibacterial ability, and antitumor efficacy for bone-implant applications

Biodegradable zinc-selenium (Zn-Se) alloys are expected to become a competitive material for implantation into hard tissues due to the antitumor function of Se in cancer prevention and treatment. However, adding Se to Zn to create Zn-Se alloys is a challenging task due to the high volatilization of the monomeric Zn and Se elements, and the immiscibility of Se and Zn. In this study, we have successfully prepared biodegradable Zn-xSe (x = 0, 1, 3, and 5 at. %) alloys using ultrahigh pressure sintering, which effectively suppressed the volatilization of monomeric Zn and Se elements and increased the solid solubility of Se in Zn. The microstructure characteristics, mechanical properties, degradation rate, anticoagulant, osteogenic ability and antitumor properties of the ultrahigh pressure sintered (UPS) Zn-Se alloys were systematically evaluated. The microstructure of the UPS Zn-Se alloys consisted of Zn matrix phases, Zn(Se) solid solution, and ZnSe second phases formed around the elemental Se phase. The UPS Zn-1Se showed the highest compressive yield strength of similar to 205.8 +/- 2.3 MPa, a fracture strain of 16.4 %, a degradation rate of 44.6 +/- 0.6 mu m/y, effective antibacterial ability against S. aureus, effective antitumor activity against Cal-27 carcinoma cells, dramatic osteogenic ability and excellent biocompatibility toward pre-osteoblast MC3T3-E1 cells. Overall, the addition of 1 at. % Se to Zn does not affect the growth of normal cells, but effectively inhibits the growth and reproduction of tumor cells and the Zn-1Se alloy is promising for orthopedic applications due to its unique combination of mechanical and biological properties.