Catechol-functionalized Chitosan/Polyvinyl alcohol hydrogel microneedles integrating multimodal antibacterial nanocomposites for enhanced wound healing

Pathogenic bacterial infections, particularly antibiotic-resistant strains, severely impede wound healing, increasing patient pain and healthcare costs. Herein, we engineered a bioinspired, adhesive and near-infrared (NIR)-responsive hydrogel microneedles (MNs) patch for transdermal delivery of multifunctional antimicrobials to treat infected wound. The patch consisted of a mussel-mimetic hydrogel matrix of 3, 4-dihydroxyphenylacetic acid-modified chitosan and poly (vinyl alcohol) (DLC/PVA). The DLC/PVA hydrogel MNs were loaded with engineered antimicrobial nanocomposites (SAMnPor@TA/Ag-HA), featuring NIR-activatable manganese porphyrin assemblies (SAMnPor), ultrasmall tannic acid-chelated silver (TA/Ag) nanoparticles, and a protective hyaluronic acid (HA) outer layer. These organic-inorganic nanocomposites conferred the DLC/PVA MNs with multimodal antibacterial activity driven by photodynamic, photothermal and metalloantimicrobial effects, including rapid disinfection under NIR irradiation and sustained antibacterial activity in the absence of light. In mouse bacterial-infected wound models, a single administration of the DLC/PVA MNs patch exerted superior antimicrobial efficacy and wound healing ability, highlighting its great potential in combating bacterial infections and promoting tissue regeneration. Compared with common hyaluronic acid methacrylated (HAMA) MNs, the DLC/PVA MNs exhibited appropriate tissue adhesion and remarkable antioxidant activity due to the integration of mussel-derived catechol groups. This study offers a promising long-term wound care strategy by integrating advanced antibacterial nanocomposites within a polysaccharide-based microneedle platform.