Background Photodynamic therapy (PDT) is a widely used therapeutic approach for eradicating bacterial biofilms in infected wound, but its effectiveness is limited by the hypoxic environment within the biofilm. This study aimed to investigate whether the efficiency of photodynamic removing biofilm is improving by providing oxygen (O2), as well as the expression of cytokines involved in infected wound healing. Methods Manganese dioxide (MnO2) nanoparticles with catalase-like activity were grown in situ on graphitic phase carbon nitride (g-C3N4, CN) nanosheets to construct an all-in-one CN-MnO2 nanozyme, which was then incorporated into poly-L-lactic acid (PLLA) to prepare CN-MnO2/PLLA wound dressing by electrospinning. Subsequently, the in vitro antibacterial biofilm ratio and antibacterial ratio of CN-MnO2/PLLA wound dressing were examined by spread plate and crystal violet staining under irradiation with 808 nm near-infrared light and 660 nm visible light. Meanwhile, the rat skin injury model was established, and hematoxylin and eosin (H&E), Masson’s, tumor necrosis factor-α (TNF-α), Arginase 1 (Arg-1), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (BFGF) were evaluated in vivo to assess the effect of CN-MnO2/PLLA wound dressing on wound healing. Results Biofilm density caused by Staphylococcus aureus and Pseudomonas aeruginosa had elimination rates of 83 and 62%, respectively, when treated with CN-MnO2/PLLA dressing. Additionally, the dressing exhibited high antibacterial efficacy against both bacteria, achieving 99 and 98.7% elimination of Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Furthermore, in vivo experiments showed that the CN-MnO2/PLLA wound dressing achieved complete healing of infected wounds on Day 14, with a wound healing rate of >99% by increasing collagen deposition, expression of anti-inflammatory cytokine Arg-1, vascularization cytokine VEGF, and epithelial cell BFGF, and inhibiting the expression of inflammatory cytokine TNF-α. Conclusions The CN-MnO2/PLLA wound dressing exhibited excellent antibacterial properties in vitro and in vivo. In addition, CN-MnO2/PLLA wound dressing accelerated rapid wound healing through an anti-inflammatory, pro-vascular regeneration and skin tissue remodeling mechanism.

中文翻译：

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聚乳酸基敷料，具有氧气生成和酶样活性，可加速光驱动的生物膜消除和伤口愈合


背景光动力疗法 （PDT） 是一种广泛使用的治疗方法，用于根除感染伤口中的细菌生物膜，但其有效性受到生物膜内低氧环境的限制。本研究旨在调查光动力去除生物膜的效率是否通过提供氧气 （O2） 以及参与感染伤口愈合的细胞因子的表达而提高。方法 在石墨相氮化碳 （g-C3N4， CN） 纳米片上原位生长具有过氧化氢酶样活性的二氧化锰 （MnO2） 纳米颗粒，构建一体化 CN-MnO2 纳米酶，然后将其掺入聚-L-乳酸 （PLLA） 中，通过静电纺丝制备 CN-MnO2/PLLA 伤口敷料。随后，在 808 nm 近红外光和 660 nm 可见光照射下，通过展板和结晶紫染色检测 CN-MnO2/PLLA 伤口敷料的体外抗菌生物膜比例和 CN-MnO2/PLLA 伤口敷料的抗菌比例。同时，建立大鼠皮肤损伤模型，体内评价苏木精和伊红 （H&E）、Masson's、肿瘤坏死因子-α （TNF-α）、精氨酸酶 1 （Arg-1）、血管内皮生长因子 （VEGF） 和碱性成纤维细胞生长因子 （BFGF），评价 CN-MnO2/PLLA 伤口敷料对伤口愈合的影响。结果 当用 CN-MnO2/PLLA 敷料处理时，金黄色葡萄球菌和铜绿假单胞菌引起的生物膜密度的消除率分别为 83% 和 62%。此外，该敷料对两种细菌均表现出很高的抗菌功效，分别实现了 99% 和 98.7% 的金黄色葡萄球菌和铜绿假单胞菌的消除。 此外，体内实验表明，CN-MnO2/PLLA 伤口敷料通过增加胶原蛋白沉积、抗炎细胞因子 Arg-1、血管化细胞因子 VEGF 和上皮细胞 BFGF 的表达，抑制炎性细胞因子 TNF-α 的表达，伤口愈合率达到 >99%。结论 CN-MnO2/PLLA 伤口敷料在体外和体内均表现出优异的抗菌性能。此外，CN-MnO2/PLLA 伤口敷料通过抗炎、促血管再生和皮肤组织重塑机制加速伤口快速愈合。