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

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. 摘要 最大限度地减少种植体周围感染, 提高种植体存活率和抗菌性是当前医务人员关注的主要问题, 为此本研究开发了钛-铜烧结合金(3 wt%和5 wt%Cu)医用种植材料。分别使用X射线衍射(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能量色散X射线能谱(EDS)、电感耦合等离子体(ICP)和视频光学接触角测量仪对合金的物相鉴定、微观结构、铜离子释放和润湿性进行了表征检测。采用抑菌圈法、平板计数法、活/死荧光染色法、扫描电镜和活性氧(ROS)染色法评价钛铜 (Ti-Cu) 合金对牙龈卟啉单胞菌和变形链球菌的抗菌活性。结果表明:Ti-Cu合金由α-Ti相和Ti 2 Cu相组成, 随着合金中Cu含量的增加, Ti 2 Cu相的含量也增加;Ti-Cu合金对两种细菌均表现出一定的抑菌活性, 且随时间的增加而增强。Ti-3Cu和Ti-5Cu对牙龈卟啉单胞菌的72 h抗菌率分别为57%和70%, 对变形链球菌的72 h抗菌率分别为63%和78%。在最初的24 h内, 这些合金释放出的Cu 2+ 最高量为0.3 mg·L −1 , 是在安全范围内。研究认为铜离子的释放和活性氧 (ROS) 的生成是抗菌的主要机制。总之, Ti-Cu烧结合金在牙科和骨科植入物领域具有广阔的应用前景。 Graphic Abstract