Bacterial biofilms are responsible for many chronic infections because antibacterial agents exhibit poor penetration into the dense matrix barrier and cannot easily reach the internal bacteria. Herein, we reported pH-responsive nanocomposites (PDA@Kana-AgNPs) that could penetrate and disperse biofilms, which were synthesized by the combination of ultrasmall silver nanoparticles (AgNPs) and kanamycin, and then coating with polydopamine. Confocal fluorescence imaging indicated that PDA@Kana-AgNPs could respond to the acidic microenvironment of biofilms, leading to biofilm-triggered on- demand drug release in situ. The zone of inhibition test and Resazurin assay showed that the combination of kanamycin and AgNPs had greater antimicrobial activity against test strains (Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Escherichia coli BL21) than when applied separately. The crystal violet staining test demonstrated that biofilms were effectively dispersed by the proposed nanocomposites. Biocompatibility was also evaluated, which showed that PDA@Kana-AgNPs were non-toxic to mammalian cells. Therefore, the proposed pH-responsive nanocomposites held great potential for efficient antibiotics delivery and showed synergistic antibacterial and antibiofilm activities. This strategy could also be used to encapsulate a variety of antibiotics in combination with other drugs or materials, thereby showing therapeutic potential in preventing biofilm-related infections and realizing fluorescence imaging in situ.

细菌生物膜是许多慢性感染的原因，因为抗菌剂对致密基质屏障的渗透性较差，并且不容易到达内部细菌。在此，我们报道了可以穿透和分散生物膜的 pH 响应纳米复合材料（PDA@Kana-AgNPs），该复合材料由超小银纳米颗粒（AgNPs）和卡那霉素结合，然后用聚多巴胺包被合成。共聚焦荧光成像表明 PDA@Kana-AgNPs 可以响应生物膜的酸性微环境，导致生物膜触发的原位按需药物释放。抑菌圈试验和刃天青试验表明，卡那霉素和AgNPs的组合对试验菌株（金黄色葡萄球菌、肺炎链球菌、铜绿假单胞菌和大肠杆菌BL21) 比单独应用时。结晶紫染色试验表明，所提出的纳米复合材料有效地分散了生物膜。还评估了生物相容性，这表明 PDA@Kana-AgNPs 对哺乳动物细胞无毒。因此，所提出的 pH 响应纳米复合材料在有效输送抗生素方面具有巨大潜力，并显示出协同抗菌和抗生物膜活性。该策略还可用于封装多种抗生素与其他药物或材料，从而在预防生物膜相关感染和实现原位荧光成像方面显示出治疗潜力。