A dual-responsive nanosystem for synergistic antibacterial therapy and inflammatory microenvironment modulation in infected diabetic wound healing.

The refractory healing of diabetic wounds represents a major clinical challenge, primarily attributed to a vicious cycle formed by persistent bacterial infection, excessive oxidative stress, and a dysregulated immune microenvironment. To simultaneously address multiple pathological barriers, an intelligent composite nanoplatform was designed and constructed in this study, integrating near-infrared (NIR) photothermal therapy, reactive oxygen species (ROS) scavenging, antimicrobial activity, and immunomodulation. A mesoporous polydopamine (MPDA) core was loaded with chlorogenic acid (CGA), a natural antioxidant, and further coated with a copper-zinc bimetallic organic framework (Cu/Zn-MOF) to fabricate Cu/Zn-MOF@CGA@MPDA NPs, exhibiting pH-responsive dissociation in the acidic infected wound microenvironment. Under 808 nm near-infrared irradiation, the fabricated NPs showed excellent photothermal performance, efficiently eliminating bacteria and biofilms in vitro. They also scavenged ROS to relieve oxidative damage and promoted macrophage polarization from the pro-inflammatory M1 to pro-healing M2 phenotype. In a diabetic rat model of infected full-thickness skin wounds, the nanoplatform achieved antibacterial and anti-inflammatory effects simultaneously. Such synergistic functions promoted collagen deposition and re-epithelialization, thereby accelerating diabetic wound healing. Histological and hematological tests verified its good biocompatibility and biosafety. This work developed a synergistic single-platform strategy for precise regulation of diabetic wound microenvironments, providing a promising therapeutic alternative for refractory diabetic wound treatment.