Photodynamically active fibres (PAFs) are a novel class of stimulus-sensitive systems capable of triggering antibiotic-free antibacterial effect on-demand when exposed to light. Despite their relevance in infection control, however, the broad clinical applicability of PAFs has not yet been fully realised due to the limited control in fibrous microstructure, cell tolerance and antibacterial activity in the physiologic environment. We addressed this challenge by creating semicrystalline electrospun fibres with varying content of poly[(l-lactide)-co-(glycolide)] (PLGA), poly(ε-caprolactone) (PCL) and methylene blue (MB), whereby the effect of polymer morphology, fibre composition and photosensitiser (PS) uptake on wet state fibre behaviour and functions was studied. The presence of crystalline domains and PS–polymer secondary interactions proved key to accomplishing long-lasting fibrous microstructure, controlled mass loss and controlled MB release profiles (37 °C, pH 7.4, 8 weeks). PAFs with equivalent PLGA:PCL weight ratio successfully promoted attachment and proliferation of L929 cells over a 7-day culture with and without light activation, while triggering up to 2.5 and 4 log reduction in E. coli and S. mutans viability, respectively. These results support the therapeutic applicability of PAFs for frequently encountered bacterial infections, opening up new opportunities in photodynamic fibrous systems with integrated wound healing and infection control capabilities.

中文翻译：

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静电纺光动力活性纤维的水解降解性、细胞耐受性和按需抗菌效果。


光动力活性纤维（PAF）是一类新型的刺激敏感系统，能够在暴露于光时按需触发无抗生素的抗菌作用。然而，尽管它们在感染控制方面具有相关性，但由于生理环境中纤维微观结构、细胞耐受性和抗菌活性的控制有限，PAF 的广泛临床应用尚未完全实现。我们通过制造具有不同含量的聚[(L-丙交酯)-共-(乙交酯)] (PLGA)、聚(ε-己内酯) (PCL) 和亚甲蓝 (MB) 的半结晶电纺纤维来解决这一挑战，从而产生效果研究了聚合物形态、纤维组成和光敏剂（PS）吸收对湿态纤维行为和功能的影响。事实证明，结晶域和 PS-聚合物二次相互作用的存在对于实现持久的纤维微观结构、受控的质量损失和受控的 MB 释放曲线（37°C，pH 7.4，8 周）至关重要。具有同等 PLGA:PCL 重量比的 PAF 在有光激活和无光激活的 7 天培养中成功促进了 L929 细胞的贴壁和增殖，同时引发大肠杆菌和变形链球菌活力分别高达 2.5 和 4 个对数减少。这些结果支持 PAF 对常见细菌感染的治疗适用性，为具有集成伤口愈合和感染控制功能的光动力纤维系统开辟了新的机会。