Development of new Ti_(50)Zr_(25)Nb_(20)Cu_(5-x)Ag_(x)high-entropy alloys with excellent antibacterial property,osteo-conductivity and biocompatibility in vitro and in vivo

A new series of medical antibacterial high-entropy alloys(HEAs)with composition Ti 50 Zr 25 Nb 20 Cu 5-x Ag x(x=0 at.%,1 at.%,and 2.5 at.%)were developed by arc-melting the mixture of pure elements under a high-purity argon atmosphere.The cytotoxicity,osteo-conductivity,and antibacterial properties of these HEAs were systematically investigated in vitro,along with their in vivo biocompatibility and antibacte-rial properties.These HEAs,especially Ti_(50)Zr_(25)Nb_(20)Cu_(2.5)Ag_(2.5),showed better antibacterial ability against Staphylococcus aureus than Ti-6Al-4V,which has a nearly 99%antibacterial rate in vitro.Moreover,ion release and cytotoxicity tests showed that these HEAs had excellent biosafety,similar to or better than that of Ti-6Al-4V.Osteoblasts were used to evaluate the osteogenic activity of these HEAs,and good osteo-conductivity was observed in vitro.In a Sprague-Dawley rat infection model,Ti_(50)Zr_(25)Nb_(20)Cu_(2.5)Ag_(2.5)showed remarkable antibacterial properties compared to Ti-6Al-4V.The in vivo biocompatibility results showed that Ti_(50)Zr_(25)Nb_(20)Cu_(2.5)Ag_(2.5)did not increase biotoxicity compared to Ti-6Al-4V.The excellent bio-compatibility and antibacterial properties of the Ti-Zr-Nb-Cu-Ag HEAs are expected to enable the pre-vention of periprosthetic/peri-implant infections in the future.