Dual-network 3D-printed recombinant collagen hydrogel with tunable mechanics and controlled Cu²⁺ release for infected...

Chronic wound healing faces challenges such as prolonged repair periods and high infection risks. Herein, we developed a 3D-printed dual-network hydrogel, RCMA/SA/Cu²⁺, capable of self-regulated copper ion release for enhanced chronic wound repair. Methacrylated recombinant collagen (RCMA) combined with sodium alginate (SA) produced a hydrogel with improved viscosity and printability, allowing precise 3D fabrication. Subsequent dual crosslinking through RCMA photopolymerization and Cu²⁺-mediated SA coordination imparted robust mechanical strength and resistance to enzymatic degradation. pH-responsive Cu²⁺ release provided antibacterial effects during the inflammatory phase and stimulated angiogenesis in the proliferative phase. Additionally, the RCMA/SA/Cu²⁺ hydrogel promotes cellular adhesion, proliferation, migration, and differentiation. In a S. aureus-infected full-thickness skin defect model in SD rats, the hydrogel exhibited potent antibacterial, anti-inflammatory, angiogenic, and tissue regenerative effects. 3D printed smart recombinant collagen composite hydrogel offers an efficient, safe biomaterial for chronic wound healing with promising clinical applications in skin tissue engineering.