3D-Printed Auxetic Hydrogel Dressings Reinforced With MXene and Carbonized Polymer Dots for Cascaded Antibacterial and Pro-Regenerative Effects in Wound Healing.

In this study, we develop a 3D bioprinted auxetic hydrogel dressing (MX/CPDs@PBGC) that incorporates Ti3C2Tx MXene (MX) and carbonized polymer dots (CPDs) for the simultaneous treatment of chronic wounds infected with multidrug-resistant (MDR) bacteria. The PBGC matrix, composed of polyvinyl alcohol (P), boric acid (B), gelatin (G), and citrate (C), provides enhanced mechanical strength, self-healing capability, and auxetic behavior, ensuring durability and adaptability to complex, mobile wound sites. The responsive release of CPDs and MXene enables the controlled delivery of therapeutics, adapting to the dynamic environment of chronic wounds. CPDs derived from mannose and arginine offer potent antibacterial and (pro-)regenerative activity, while MXene contributes antioxidative and anti-inflammatory functions. In a diabetic mouse model with MRSA-infected wounds, the hydrogel significantly accelerated healing, reduced bacterial load, and outperformed commercial 3 M antibacterial dressings. Histological analysis revealed enhanced collagen deposition, angiogenesis, and epithelialization, as well as increased polarization of macrophages toward the M2 phenotype. Additionally, treatment with MX/CPDs@PBGC resulted in a marked reduction in pro-inflammatory cytokines and an increase in anti-inflammatory cytokines, confirming effective infection control and modulation of inflammation. These results highlight the potential of MX/CPDs@PBGC as a multifunctional dressing for treating MDR-infected wounds and support its further clinical investigation.