Facile crystallized-AIE-photosensitizer functionalized hydrogel for antimicrobial photodynamic therapy and wound recovery.

The development of wound dressings with high antibacterial efficacy is critical for the treatment of bacterial infections. Antimicrobial photodynamic therapy (aPDT) is a promising approach, and aggregation-induced emission photosensitizers (AIE-PSs) have garnered significant attention for their enhanced performance in the aggregated state, where the restriction of intramolecular motion serves as the underlying mechanism. However, conventional aggregation often leads to loosely packed PSs, leaving space for intramolecular motion. Crystallization provides a powerful strategy for forming tightly packed molecular aggregates. In this study, an AIE-PS (MeTS2IC) was designed by attaching a propeller-like moiety to rigid planar groups. The former enables intramolecular motion and maintains a twisted conformation, while the latter facilitates crystallization. A bactericidal function alone is insufficient for optimal wound healing; thus, a hydrogel matrix was introduced for biocompatibility. The AIE-PS can easily form microcrystals (MCs) when its concentrated solution is added to the pre-gel solution. Subsequent photo-crosslinking in situ forms the light-activated antibacterial AIE-PS-MCs@hydrogel dressing on the wound. Under white light irradiation, the dressing effectively eliminates bacteria, reduces inflammation, promotes vascular network recovery, and accelerates wound healing. The combination of AIE-PS MCs with hydrogel offers a simple, effective strategy for managing infected wounds, with promising potential for future clinical applications.