Eu3+-mediated dual-crosslinked collagen-mimetic peptide/sodium alginate hydrogel for 3D-printed skin wound dressings

The development of multifunctional bioinks that simultaneously possess robust mechanical properties, bioactivity, and high printability remains a central challenge in tissue engineering. In this study, a biofunctional 3D-printable hydrogel based on a collagen-mimetic peptide (CMP) and sodium alginate (SA) was constructed for the treatment of full-thickness skin defects. Europium ions (Eu 3+ ) coordinated with both the carboxyl groups of SA and the aspartic acid residues of the CMP-DD peptide, forming a reinforced dual-network structure with enhanced stability and mechanical strength, which enables precise extrusion-based 3D printing with excellent shape fidelity. Subsequent incorporation of calcium ions (Ca 2+ ) for secondary crosslinking further endows the hydrogel with tunable elasticity and superior structural durability. The composite hydrogel significantly promoted cell adhesion and proliferation, while exhibiting pronounced antibacterial and anti-inflammatory properties. In a Sprague–Dawley rat full-thickness skin defect model, it significantly accelerates wound healing, enhances granulation tissue formation, promotes collagen deposition, and improves re-epithelialization. This dual-coordination CMP-based composite hydrogel integrates outstanding mechanical performance, bioactivity, and printability, offering an innovative and promising strategy for the design of high-performance bioinks and the advancement of skin tissue regeneration.