Precious metal-based metallic glasses (BMGs) have desirable properties for a variety of medical applications (e.g., stents, dental and osteosynthesis devices). In particular, their high mechanical strength and storage of elastic energy, high corrosion resistance, and thermoformability in the supercooled liquid regime set them apart from traditional biomedical alloys. Antibacterial properties are an additional attribute in demand for medical applications. Device-related infections are a serious problem that accounts for a large portion of implant failures and can threaten the life of patients [1]. Here we report our first results with the objective to impart $Pd_{43}Cu_{27}Ni_{10}P_{20}$ (Pd-BMG) with antibacterial properties. Pd-BMG is biocompatible [2], and shows high thrombogenic resistance [3]. Furthermore, it has one of the lowest critical cooling rates of about 1.5 K/s (0.1 K/s when fluxed) [4], enabling industrial production of bulky metallic glass parts using common industrial techniques of casting and machining. However, its exceptional corrosion resistance limits the release of Cu ions. In an attempt to increase the release of antibacterial ions, we add small amounts of additional antibacterial elements Ag and Ga. Such additions might in fact provide a synergistic antibacterial effect, i.e. develop in combination a significantly stronger effect at low concentrations than individually at higher concentrations [5] (see Figure 1). We assess the effects of minor additions of Ag and Ga (1 to 4 at%) on the glass forming ability, hardness, and viscosity in the supercooled liquid regime. Additionally, we quantify the release of antibacterial ions in a simulated biological environment.

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2. Hua, N. et al. A biocompatible Pd-based BMG with excellent corrosive-wear resistance for implant applications. Intermetallics 124, 106847 (2020).

3. Cihova, M. et al. Palladium-Based Metallic Glass with High Thrombogenic Resistance for Blood-Contacting Medical Devices. Advanced Functional Materials. 2108256 (2021)

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5. Wang, X. et al. The synergistic antibacterial activity and mechanism of multicomponent metal ions-containing aqueous solutions against Staphylococcus aureus. J. Inorg. Biochem. 163, 214–220 (2016)