Photodynamically active AIE-functionalised casein nanofibers for antibacterial wound management in epidermolysis bullosa

Abstract

Epidermolysis bullosa (EB) is a debilitating genetic disorder characterized by extreme skin fragility and chronic wound formation, often complicated by bacterial infections. Current wound dressings provide limited protection against infection and may induce cytotoxicity or mechanical trauma. Herein, we report a multifunctional nanofibrous dressing based on casein/poly(vinyl alcohol) (PVA) integrated with an aggregation-induced emission (AIE) photosensitiser (PS) for enhanced antibacterial performance. Bilayer nanofibrous mats were fabricated via multi-nozzle electrospinning, combining a mechanically robust PVA support layer with a bioactive casein-rich surface. Post-fabrication, glutaraldehyde crosslinking improved structural stability, while plasma polymerization enabled immobilization of an AIE PS (TPAQ-PF₆) onto the fiber surface. The resulting materials exhibited tunable wettability, preserved nanofibrous morphology, and stable AIE fluorescence. Under light irradiation, AIE-functionalised dressings generated reactive oxygen species (ROS), leading to significant antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Fluorescence imaging confirmed enhanced ROS production at the material surface. Importantly, cytocompatibility assays using keratinocytes and fibroblasts demonstrated good cytocompatibility, highlighting suitability for potential wound-contact applications. Overall, this work presents a biocompatible, photodynamically active dressing platform that integrates natural polymers with advanced AIE technology, offering a promising strategy for infection control in fragile skin conditions such as EB.