Background Bacterial infection, tissue hypoxia and inflammatory response can hinder infected wound repair. This study aimed to develop a multifunctional specific therapeutic photo-activated release nanosystem [HMPB@MB@AuNPs@PMB@HA (HMAPH)] by loading photosensitizer methylene blue (MB) into hollow mesoporous Prussian blue nanostructures and modifying the surface with gold particles, polymyxin B (PMB) and hydrophilic hyaluronic acid. Methods The HMAPH was characterized using transmission electron microscopy, UV–vis, Fourier-transform infrared spectroscopy, X-ray diffraction and X-ray photon spectroscopy. The photothermal performance, iron ion release and free radical generation of the HMAPH were measured under different conditions to investigate its thermo-responsive cascade reaction. The antibacterial ability of HMAPH was investigated using live/dead fluorescence tests. The morphology and membrane integrity of Pseudomonas aeruginosa (P. aeruginosa) were investigated using transmission electron microscopy. The anti-biofilm activity of HMAPH was evaluated using crystal violet and SYBR Green I staining. Finally, we established a mouse model of a skin wound infected by P. aeruginosa to confirm the in vivo effectiveness of HMAPH. We used immunofluorescent staining, hematoxylin–eosin staining, Masson staining and enzyme-linked immunosorbent assay to examine whether HMAPH promoted wound healing and reduced inflammatory damage. Results In this study, hyaluronic acid was decomposed under the action of hyaluronidase. Also, the exposed nanomaterials specifically bound to the outer membrane of P. aeruginosa through PMB to increase the membrane sensitivity to photodynamic treatment. Under dual-light irradiation, a large amount of iron ions released by HMAPH underwent a Fenton reaction with H2O2 in bacteria to generate hydroxyl radicals (•OH), enabling direct killing of cells by hyperthermia. Additionally, the photodynamic activity of MB released by photo-induced activation led to the generation of reactive oxygen species, achieving synergistic and effective inhibition of P. aeruginosa. HMAPH also inhibited biofilm formation and downregulated the expression of virulence factors. In vivo experiments revealed that HMAPH accelerated the healing of P. aeruginosa-infected wounds by promoting angiogenesis and skin regeneration, inhibiting the inflammatory response and promoting M1 to M2 polarization. Conclusions Our study proposed a strategy against bacteria and biofilms through a synergistic photothermal–photodynamic–Fenton reaction, opening up new prospects for combating biofilm-associated infections.

中文翻译：

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热响应级联抗菌平台，可精确去除生物膜并增强伤口愈合


背景细菌感染、组织缺氧和炎症反应会阻碍感染伤口的修复。本研究旨在通过将光敏剂亚甲基蓝（MB）负载到中空介孔普鲁士蓝纳米结构中并用金颗粒修饰表面，开发一种多功能特异性治疗光激活释放纳米系统[HMPB@MB@AuNPs@PMB@HA（HMAPH）]。多粘菌素 B (PMB) 和亲水性透明质酸。方法使用透射电子显微镜、紫外可见光谱、傅里叶变换红外光谱、X 射线衍射和 X 射线光子光谱对 HMAPH 进行表征。在不同条件下测量了 HMAPH 的光热性能、铁离子释放和自由基生成，以研究其热响应级联反应。使用活/死荧光测试研究 HMAPH 的抗菌能力。使用透射电子显微镜研究了铜绿假单胞菌（P. aeruginosa）的形态和膜完整性。使用结晶紫和 SYBR Green I 染色评估 HMAPH 的抗生物膜活性。最后，我们建立了铜绿假单胞菌感染皮肤伤口的小鼠模型，以证实 HMAPH 的体内有效性。我们采用免疫荧光染色、苏木精-伊红染色、Masson染色和酶联免疫吸附试验来检测HMAPH是否促进伤口愈合并减少炎症损伤。结果本研究中透明质酸在透明质酸酶的作用下被分解。此外，暴露的纳米材料通过PMB特异性结合到铜绿假单胞菌的外膜上，以增加膜对光动力处理的敏感性。 在双光照射下，HMAPH释放的大量铁离子与细菌体内的H2O2发生芬顿反应，生成羟基自由基（•OH），从而实现热疗直接杀伤细胞。此外，光诱导激活释放的MB的光动力活性导致活性氧的产生，实现对铜绿假单胞菌的协同有效抑制。 HMAPH 还抑制生物膜形成并下调毒力因子的表达。体内实验表明，HMAPH通过促进血管生成和皮肤再生、抑制炎症反应和促进M1到M2极化来加速铜绿假单胞菌感染伤口的愈合。结论我们的研究提出了一种通过协同光热-光动力-芬顿反应对抗细菌和生物膜的策略，为对抗生物膜相关感染开辟了新的前景。