Copper release and ROS in antibacterial activity of Ti‐Cu alloys against implant‐associated infection

Abstract Enhancing the antibacterial properties of the currently used implant materials is a major concern of healthcare providers to minimize the impact of peri‐implant infection and improve implant survival rates. In this study, titanium–copper sintered alloys (3 wt% and 5 wt% Cu) were developed for medical implant applications. The phase identification, microstructure, copper ions release, and wettability of these alloys were evaluated using X‐ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), energy‐dispersive X‐ray spectroscope (EDS), inductively coupled plasma spectroscope (ICP) and drop shape analyzer. The antibacterial activities of Ti‐Cu alloys against Porphyromonas gingivalis and Streptococcus mutans were evaluated using inhibition zone assay, plate counting assay, live/dead fluorescent staining, SEM and reactive oxygen species (ROS) staining assay. The results demonstrated that Ti‐Cu alloys are composed of α‐Ti and Ti 2 Cu phases that increased with increased Cu content of the alloy. Ti‐Cu alloys exhibited antibacterial activity against both bacteria species in a time‐dependent manner. The antibacterial rates of Ti‐3Cu and Ti‐5Cu after 72 h were 57% and 70% against Porphyromonas gingivalis and 63% and 78% against Streptococcus mutans , respectively. The highest amount of Cu 2+ released from these alloys was 0.3 mg·L −1 during the first 24 h, within the safe range. The copper ions release and ROS production were suggested as the main antibacterial mechanisms. Overall, Ti‐Cu sintered alloys are promising materials for dental and orthopedic implants.