Antibacterial alloys are widely applied to reduce the incidence of medical-implant-associated infection. Copper (Cu) and silver (Ag) are commonly used in antibacterial alloys; however, rare earth elements, such as Cerium (Ce), are now gaining attention because their low trace is sufficient for killing bacteria. Accordingly, the antibacterial activity of Copper48-Silver48-Cerium4 (CuAgCe4) alloys with different crystalline structures was investigated. The immersion approach was employed for alloys cultured with Escherichia coli, and a direct contact method was used for alloys cultured with Staphylococcus aureus. Surface morphology was observed when alloys were made, and the crystalline structures of alloys were examined before and after being cultured with bacteria. The immersion method revealed that all the CuAgCe4 alloy samples could inhibit the growth of Escherichia coli, and the crystallized structures were distorted after the alloys were cultured with bacteria. Conversely, the direct contact approach showed the crystalline structures of CuAgCe4 alloys remained unchanged after the culture with Staphylococcus aureus, thereby indicating that the antibacterial activity did not correspond to the crystalline structures. Despite the lack of clarity surrounding the possible antibacterial mechanisms of CuAgCe4 alloy, the current findings demonstrate the potential antibacterial effects of CuAgCe4 alloy in medical implants.
