Carbon quantum dots embedded electrospun nanofibers for efficient antibacterial photodynamic inactivation

Faced with the emergence and proliferation of antibiotic resistant pathogens, novel nonspecific materials and approaches are required. Herein, we employed electrospinning technology to fabricate nanofibers with antibacterial photodynamic inactivation. This material combines polyacrylonitrile, as a photostable polymer, and biocompatible carbon quantum dots. The resulted nanofibers were successfully characterized by physical and spectroscopic methods. The microbicidal reactive oxygen species (i.e., singlet oxygen) upon illumination was confirmed, and cytotoxicity assay demonstrated that the nanofibers had low cytotoxicity and good biocompatibility. Antibacterial photodynamic inactivation studies demonstrated broad antibacterial efficacy of Gram-negative Escherichia coli ATCC-8099 (99.9999+%, 6 log units inactivation), Gram-negative Pseudomonas aeruginosa CMCC (B) 10104 (99.9999+%, 6 log units inactivation), and Gram-positive Bacillus subtilis CMCC (B) 63501 (99.9999+%, 6 log units inactivation) upon illumination with visible light (Xe lamp, 500 W, 12 cm sample distance, λ ≥ 420 nm, 1.5 h). However modest inactivation results were observed against Gram-positive Staphylococcus aureus ATCC-6538 (98.3%, 1.8 log units inactivation). Owing to the prepared nanofibers exhibiting efficient antibacterial activity against Gram-negative and Gram-positive bacteria, such materials could be potentially used in anti-infective therapy.