Bacterial infections, especially chronic infections caused by bacterial biofilms, have become a worldwide threat to public health. Encouragingly, the synergistic actions of two or more antibacterial drugs have been proven to be effective in treating refractory bacterial infections. Herein, we fabricated a robust antibacterial nanohybrid, the colistin-loaded polydopamine nanospheres (PDA NSs) decorated uniformly with small silver nanodots (u-CPSs), and the u-CPSs could realize synergistic bactericidal performance for combating bacterial infections. PDA NSs, as an adhesive nanocarrier, could bind to the bacterial surfaces, where the drugs (colistin and silver ions) on the PDA surfaces could be released persistently via a near-infrared laser-triggered manner. Interestingly, compared with colistin-loaded PDA NSs decorated sparsely with large silver nanoparticles (s-CPSs), the u-CPSs exhibited stronger antibacterial and antibiofilm effects. We have also demonstrated that the u-CPSs could disrupt the cell walls/membranes of Gram-negative Escherichia coli bacteria and induce the generation of toxic reactive oxygen species within the bacteria. Collectively, the present work exemplifies the exquisite design and synthesis of PDA-based nanohybrids for achieving synergistic antibacterial and antibiofilm activities, which may promote the development of more powerful nanoagents to fight against bacterial infections.

中文翻译：

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载有粘菌素的聚多巴胺纳米球均匀装饰有银纳米点：具有改进的抗菌和抗菌膜性能的纳米混合平台

细菌感染，特别是由细菌生物膜引起的慢性感染，已成为全球公共卫生的威胁。令人鼓舞的是，两种或多种抗菌药物的协同作用已被证明可有效治疗难治性细菌感染。在这里，我们制造了一种强大的抗菌纳米混合物，负载粘菌素的聚多巴胺纳米球（PDA NSs）均匀装饰有小银纳米点（u-CPSs），并且u-CPSs可以实现协同杀菌性能以对抗细菌感染。PDA NSs 作为一种粘性纳米载体，可以与细菌表面结合，通过近红外激光触发的方式，PDA 表面的药物（粘菌素和银离子）可以持续释放。有趣的是，与用大银纳米粒子（s-CPSs）稀疏修饰的载有粘菌素的PDA NSs相比，u-CPSs表现出更强的抗菌和抗生物膜作用。我们还证明了 u-CPS 可以破坏革兰氏阴性菌的细胞壁/膜大肠杆菌和诱导细菌内有毒活性氧的产生。总的来说，目前的工作体现了基于 PDA 的纳米杂化物的精细设计和合成，以实现协同抗菌和抗生物膜活性，这可能会促进开发更强大的纳米剂来对抗细菌感染。