Copper-Coordinated Hyaluronic Acid Hydrogels with Antibacterial and Anti-Inflammatory Activities

Chronic infected wounds are often characterized by persistent bacterial colonization, biofilm formation, excessive oxidative stress, and prolonged inflammation, which severely impair tissue regeneration. To address these challenges, a multifunctional wound dressing capable of antibacterial activity and microenvironment modulation was developed. In this study, amide-modified hyaluronic acid (HA-ADH) was used as the matrix, and a dynamic coordination network was constructed via Cu²⁺-hydrazide interactions to form an in situ HA-Cu hydrogel. Curcumin-loaded DSPE-PEG2000 micelles were further incorporated to obtain a pH-responsive composite hydrogel (HA-Cu/Cur). The prepared hydrogel exhibited a porous interconnected structure, along with favorable injectability, self-healing capability, tissue adhesiveness, moderate swelling, controllable degradability, and pH-responsive behavior under acidic conditions. In vitro antibacterial assays demonstrated that both HA-Cu and HA-Cu/Cur effectively inhibited the growth and biofilm formation of Escherichia coli and Staphylococcus aureus. The antibacterial activity was associated with disruption of bacterial morphology, depletion of intracellular ATP, and induction of reactive oxygen species, while HA-Cu/Cur showed enhanced performance in antibiofilm activity and oxidative stress-related effects compared with HA-Cu. Cytocompatibility studies revealed that the hydrogel extracts exhibited negligible cytotoxicity toward L929 fibroblasts and RAW 264.7 macrophages, while promoting fibroblast migration and significantly reducing the expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in lipopolysaccharide-stimulated RAW 264.7 cells, with HA-Cu/Cur showing a more pronounced anti-inflammatory effect. In summary, the HA-Cu/Cur hydrogel integrates the antibacterial and pro-healing properties of Cu²⁺ with the antioxidant and anti-inflammatory activities of curcumin. The hydrogel effectively inhibited the growth and biofilm formation of both E. coli and S. aureus, reduced the expression of TNF-α, IL-6, and IL-1β in LPS-stimulated macrophages, and promoted fibroblast migration, demonstrating its potential as a multifunctional wound dressing for the management of infected wounds.