Embedding AIE-type Ag28Au1 nanoclusters within ZIF-8 for improved photodynamic wound healing through bacterial eradication

Abstract

Designing antibacterial agents with rapid bacterial eradication performance is paramount for the treatment of bacteria-infected wounds. Metal nanoclusters (NCs) with aggregation-induced emission (AIE) have been considered as novel photodynamic antibacterial agents without drug resistance, but they suffer from poor photostability and low charge carrier separation efficiency. Herein, we report the design of a photodynamic antibacterial agent by encapsulating AIE-type AgAu NCs (Ag₂₈Au₁ NCs) into a zeolitic Zn(2-methylimidazole)₂ framework (ZIF-8). The encapsulation of AIE-type Ag₂₈Au₁ NCs into porous ZIF-8 could not only enhance the photostability of Ag₂₈Au₁ NCs by inhibiting their aggregation but also promote the separation of photoinduced charge carriers, resulting in the rapid generation of destructive reactive oxygen species (ROS) for bacterial killing under visible-light irradiation. Consequently, the as-designed photodynamic Ag₂₈Au₁ NCs@ZIF-8 antibacterial agent could rapidly eliminate 97.7% of Escherichia coli (E. coli) and 91.6% of Staphylococcus aureus (S. aureus) within 5 min in vitro under visible light irradiation. Furthermore, in vivo experimental results have highlighted the synergistic effect created by AIE-type Ag₂₈Au₁ NCs and ZIF-8, enabling Ag₂₈Au₁ NCs@ZIF-8 to effectively eradicate bacteria in infected areas, reduce inflammation, and promote the generation of blood vessels, epithelial tissue, and collagen. This synergistic effect promoted the healing of S. aureus-infected wound, with nearly 100% of wound recovery within 11 days. This work may be interesting because it sheds light on the design of metal NC-based photodynamic nanomedicine for bacteria-infected disease treatment.