From molecular charge engineering to photodynamic fibrous dressings: electrospun cellulose acetate membranes for infected wound healing

Infected wounds remain difficult to manage because bacterial colonization, biofilm formation, and persistent inflammation severely hinder tissue regeneration, while conventional antibiotic therapy is increasingly challenged by antimicrobial resistance. Herein, we report a visible-light-responsive antibacterial fibrous dressing by integrating a charge-engineered aggregation-induced emission (AIE) photosensitizer into electrospun cellulose acetate (CA) membranes. In this work, the non-cationic AIE photosensitizer is denoted as PS, while its cationic analogue is denoted as PS-1. The molecular cationization strategy endows the photosensitizer PS-1 with enhanced excited-state charge-transfer characteristics, a reduced energy gap, and promoted intersystem crossing, thereby enabling synergistic Type I/Type II reactive oxygen species generation under visible-light irradiation. Benefiting from the favorable spinnability of CA, PS-1 is homogeneously embedded into the fibrous matrix to form free-standing membranes with uniform morphology, good mechanical compliance, and suitable moisture-vapor permeability for wound coverage. Compared with the non-charged analogue, PS-1 exhibits markedly enhanced photodynamic antibacterial activity against both Staphylococcus aureus and Escherichia coli while maintaining low dark cytotoxicity and good cytocompatibility. More importantly, the CA@PS-1 dressing significantly accelerates the healing of S. aureus -infected full-thickness wounds in vivo, as evidenced by rapid wound closure, improved re-epithelialization, enhanced collagen deposition, promoted angiogenesis, and reduced inflammatory responses, without detectable systemic toxicity. This work provides an effective engineering strategy for coupling charge-regulated AIE photosensitizers with carbohydrate polymer electrospun dressings, and offers a promising platform for visible-light-activated anti-infective biomaterials.