Dual-Cross-linked Methylacrylated Collagen-DPPA Bioinks for Precision DLP Bioprinting and Accelerated Skin Wound Healing

Digital light processing (DLP) bioprinting, known for its speed and precision, has become a key tool in disease modeling and regenerative medicine. Yet, creating bioinks with optimal printability, bioactivity, and cell-supporting capacity remains a major challenge. Here, we introduce a novel dual-network collagen-based bioink, methyl acrylated collagen-dimethylphenylphosphonate (CMA-DPPA), which enables the fabrication of mechanically robust and highly printable cell-laden constructs through DLP 3D bioprinting. The CMA-DPPA hydrogel is synthesized by cross-linking collagen with DPPA, followed by photo-crosslinking with CMA; this dual-cross-linking approach markedly improves printing fidelity, mechanical strength, and enzymatic degradation resistance of the 3D-printed constructs. The CMA-DPPA hydrogel exhibits excellent biocompatibility, effectively promoting cell adhesion, proliferation, and migration. In a rat model of full-thickness skin defects, CMA-DPPA hydrogel facilitated organized collagen fiber deposition and accelerated epidermal regeneration, thereby expediting wound closure. CMA-DPPA bioink enables precise, robust scaffold fabrication, showing great promise for DLP-based tissue engineering and regenerative medicine.