Killing harmful bacteria in biofilms is a major challenge for current root canal therapy. Although traditional chemical disinfectants have a good bactericidal effect on plankton, they have little efficiency for the removal and sterilization of bacterial biofilms, and even lead to the emergence of bacterial resistance and high toxic side effects. Herein, we propose for the first time biosafe nanocomposites that integrate photothermal and peroxidase-like catalytic activity for efficient removal and killing of bacterial biofilms in root canals. The integration of gold (core) and copper (Ⅰ, Ⅱ) sulfide (shell) shows excellent catalytic effect, which can catalyze the decomposition of hydrogen peroxide at biosafe concentrations to hydroxyl radicals for efficient removal of biofilms. Moreover, studies on the mechanism of antibiofilm showed that the nanocomposites (Au@Cu_2-xS) have significant degradation effects on proteins and polysaccharides-the main components of biofilm. The in vitro results indicated that the synergism of free radical and heat shows higher sterilization rate against both gram-positive Enterococcus faecalis and gram-negative Fusobacterium nucleus, compared with free radical and heat treatment alone. More importantly, the bactericidal results on isolated dental slices and in root canal models and beagle dog demonstrated the Au@Cu_2-xS is highly effective in inactivating the bacteria in biofilms. Hence this safe and synergistic antimicrobial system has great potential in antibiofilm-oriented root canal therapy.

杀死生物膜中的有害细菌是当前根管治疗的主要挑战。尽管传统的化学消毒剂对浮游生物具有良好的杀菌作用，但它们对细菌生物膜的去除和灭菌效率不高，甚至导致出现细菌抗性和高毒副作用。在此，我们首次提出了将光热和过氧化物酶样催化活性整合在一起的生物安全纳米复合材料，用于有效去除和杀死根管中的细菌生物膜。金（核）和铜（Ⅰ，Ⅱ）硫化物（壳）的结合表现出优异的催化作用，可以催化生物安全浓度的过氧化氢分解为羟基自由基，从而有效去除生物膜。而且，_2-x S）对蛋白质和多糖（生物膜的主要成分）具有明显的降解作用。的体外结果表明，自由基和热示出了协同作用越高杀菌率对革兰氏阳性粪肠球菌和革兰氏阴性梭杆菌核，用单独的自由基和热处理进行比较。更重要的是，在孤立的牙齿切片上以及在根管模型和比格犬中的杀菌结果表明，Au @ Cu _2-x S在灭活生物膜中的细菌方面非常有效。因此，这种安全且协同的抗菌系统在面向抗生物膜的根管治疗中具有巨大的潜力。