Ag nanocomposites (NAs) have been found to induce irreversible harm to pathogenic bacteria, however, NAs tend to aggregate easily when used alone. These nanocomposites also show increased toxicity and their underlying antibacterial mechanism is still unknown. In short, practical applications of NA materials face the following obstacles: elucidating the mechanism of antibacterial action, reducing cytotoxicity to body cells, and enhancing antibacterial activity. This study synthesized a core-shell structured ZnFeO @Cu-ZIF-8 @Ag (FUA) nanocomposite with high antibacterial activity and low cytotoxicity. The nanocomposites achieved a 99.99 % antibacterial rate against () and tetracycline-resistant ( - ), in under 20 min at 100 μg/mL. The nanocomposites were able to inactivate due to the gradual release of Cu, Zn, and Ag ions, which synergistically form •OH from FUA in an aerobic environment. The presence of •OH has significant effects on the antibacterial activity. The released metal ions combine with •OH to cause damage to the bacterial cell wall, resulting in the leakage of electrolytes and ions. Moreover, in comparison to NA, the toxicity of FUA is considerably reduced. This study is expected to inspire the development of other silver-based nanocomposite materials for the inactivation of drug-resistant bacteria.

中文翻译：

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金属纳米复合材料对大肠杆菌的抗菌作用


研究发现银纳米复合材料 (NA) 会对病原菌造成不可逆的伤害，但单独使用时，NA 很容易聚集。这些纳米复合材料还表现出增加的毒性，其潜在的抗菌机制仍不清楚。总之，NA材料的实际应用面临以下障碍：阐明抗菌作用机制、降低对机体细胞的细胞毒性、增强抗菌活性。本研究合成了一种核壳结构的 ZnFeO @Cu-ZIF-8 @Ag (FUA) 纳米复合材料，具有高抗菌活性和低细胞毒性。纳米复合材料在 100 μg/mL 浓度下，在 20 分钟内对 () 和四环素耐药 (-) 的抗菌率达到 99.99%。由于Cu、Zn和Ag离子的逐渐释放，纳米复合材料能够失活，这些离子在有氧环境中协同从FUA形成·OH。 •OH的存在对抗菌活性有显着影响。释放出的金属离子与·OH结合，对细菌细胞壁造成损伤，导致电解质和离子渗漏。此外，与NA相比，FUA的毒性大大降低。这项研究有望激发其他用于灭活耐药细菌的银基纳米复合材料的开发。