Injectable protocatechuic acid based composite hydrogel with hemostatic and antioxidant properties for skin regeneration

Acute skin injuries require timely and effective treatment. Injectable self-healing hydrogels are a very promising approach, but they face many challenges because of the complex microenvironments of skin wound. Although hydrogels have been extensively studied for multifunction, injectable self-healing hydrogels with both hemostatic and antioxidant properties are rare. In this paper, gelatin grafted protocatechuic acid (GT-PCA) and oxidized-dextran (Odex) were used to engineer GT-PCA/Odex composite hydrogels via Schiff base reaction. The in vitro experimental results show that the hydrogels not only are injectable, self-healing, hemostatic, antioxidant, but also have good degradability, adhesion and biocompatibility. Further, the hydrogels can promote wound healing in full-thickness mouse skin defect models by reducing inflammation and increasing angiogenesis, collagen deposition and granulation tissue formation. Notably, the preparation method of GT-PCA/Odex hydrogels is gentle and simple, the hydrogel system has bright prospects in the treatment of acute skin injury and is expected to be applied in clinical trials.