Fluorescent Gold Nanoclusters-Loaded Ultra-Flexible Hydrogel Microneedles for Nanozyme-Photothermal Synergistic Antibacterial Treatment and Wound pH Visualization Monitoring

Currently, the monitoring and treatment of infected wounds remain a clinical challenge. Wound patches possessing potent antibacterial properties and sensing functionalities have attracted significant research attention. Herein, we present the development of a multifunctional hydrogel microneedle patch incorporating gold nanoclusters (Au NCs) for simultaneous bacterial infection therapy and real-time wound exudate pH visual monitoring. The patch matrix comprises a photo-crosslinkable hydrogel system based on methacrylated chitosan (CSMA) and polyvinyl alcohol (PVA), forming hydrogel microneedle arrays comprising high-strength needle tips and ultra-flexible substrate. Controlled release of Au NCs is achieved through the swelling of the hydrogel matrix and subsequent biodegradation. Benefiting from the synergistic integration of Au NCs' cell-penetrating peptide ligand and ultrasmall size-dependent effects, intrinsic nanozyme activity, and robust photothermal conversion capability, the microneedle patch demonstrates exceptional in vitro antimicrobial efficacy while significantly accelerating in vivo wound healing processes. The pH-sensing functionality enables semi-quantitative analysis of wound exudate acidity through UV-excited fluorescence intensity variations of Au NCs. Therefore, this work proposes an integrated strategy of the therapeutic-diagnostic platform for advanced wound management by combining synergistic antimicrobial action with dynamic physiological parameter monitoring. Although the sensitivity and anti-interference capability of the in vivo pH sensing module should be further enhanced, such multifunctional microneedle patches hold substantial translational potential for improving clinical outcomes in infected wound care.