A mechanically tunable photo-cured hydrogel system based on methacrylated collagen-keratin inter-penetrating networks for rapid and enhanced wound healing.

Conventional hydrogel wound dressings have non-tunable mechanical properties and serve only as passive barriers, resulting in slow wound healing. Advanced hydrogel dressings that can stimulate wound contraction and tissue deformation can potentially accelerate the healing of chronic wounds characterized by long healing times and high infection risk. In this study, we developed injectable photo-cured methacrylated collagen-keratin interpenetrating network (ColMA-K@IPN) hydrogels for rapid enhanced wound healing. Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (NMR) analyses proved the formation of methacrylated collagen (ColMA) by condensation reaction between collagen and methacrylic anhydride. Rheological analysis of ColMA hydrogels revealed that higher ColMA concentrations, longer UV irradiation times, and higher testing temperatures resulted in higher storage (G') and loss (G") moduli. The G' of ColMA-K@IPN decreased as keratin concentration increased because of the hindrance of self-assembly of collagen by hydrogen bond formation between collagen and keratin. Cell viability and proliferation tests revealed all tested ColMA hydrogels (2, 3, and 4 wt% ColMA) and ColMA-K@IPN (0.1, 0.5, and 1.0 wt% keratin) were biocompatible. In vitro and In vivo tests including cell scratch assay, RT-qPCR, an animal study, and histopathological evaluation demonstrated that ColMA-K0.5@IPN has superior wound healing ability. Our results suggest that ColMA-K0.5@IPN has the clinical potential for rapid enhanced wound healing.