Biomolecular microneedles loaded with MXenes/CuS heterojunction improve biofilm management in chronic wounds via activating nanozyme-like reactions and bacterial ferroptosis

Bacterial biofilm, which can produce cytotoxic metabolites and debris, activate hazardous immune responses, and destroy the microenvironment necessary for skin tissue regeneration, frequently obstructs wound healing. When bacteria form biofilms, they make extracellular polymeric substances (EPS) and have a dense structure that makes them harder to treat than free bacteria. Anti-biofilm wound dressings are currently advancing the clinical approaches to managing chronic wounds. A MXenes/CuS heterojunction was first prepared using a hydrothermal method and then incorporated into the tip areas of photo-crosslinked methacrylate gelatin (GelMA) micro-needles, which had double-layer structures and were termed GTCM microneedles. The results indicated that GTCM microneedles possessed favorable physicochemical characteristics, photothermal efficacy, and biocompatibility. GTCM microneedles, in conjunction with moderate photothermal treatment (MPTT), demonstrated effective broad-spectrum antibacterial and anti-biofilm properties, attributable to extracellular nanozyme-like reactions and intercellular bacterial ferroptosis. GTCM microneedles combined with MPTT could also accelerate S. aureus-infected wound healing via various mechanisms, such as promoting cell proliferation, M2 macrophage polarization, vascularization, and collagen deposition. This study not only developed a MXenes/CuS heterojunction-laden biomolecular microneedle with translational potential but also revealed the ferroptosis interactions between bacterial cells and micro-nano materials.