Structural color-based microneedle patch with NIR-triggered on-demand drug release for intelligent treatment of infected wounds

Bacterial-infected wounds present a critical clinical challenge due to persistent inflammation, impaired angiogenesis, and the lack of real-time treatment monitoring. To address these issues, we developed an innovative colloidal crystal hydrogel microneedle (CT MNs) patch based on CuS nanoparticles (CuS NPs) and tannic acid-berberine nanoparticles (TB NPs). This system integrates synergistic antibacterial/antioxidant therapy with structural color-based drug release self-reporting capability. Specifically, the CT MNs combine photothermal CuS NPs for near‑infrared (NIR)-triggered hyperthermia and temperature‑controlled drug release, the release of TB NPs for potent antibacterial/antioxidant activities, and the color changes of the inverse opal colloidal crystal for real‑time monitoring of drug release. In vitro assays demonstrated strong antibacterial effects (95.65% and 95.92% against E. coli and S. aureus, respectively) and outstanding ROS‑scavenging capacity (92.93% for DPPH and 97.36% for ABTS⁺). In infected rat models, the CT MNs + NIR group achieved rapid wound closure (94.41% by day 10), significantly outperforming the controls. This accelerated healing was attributed to the synergistic effects of photothermal ablation, TB NPs-mediated bacterial clearance, and ROS-scavenging-driven inflammation alleviation. Therefore, this work presents a theranostic dressing that merges targeted combination therapy with non‑invasive optical monitoring of drug release, offering a promising strategy for intelligent wound management.