Water-retaining and separable adhesive hydrogel dressing for wound healing without secondary damage

As a type of wound dressings, adhesive hydrogel dressings have been studied widely. However, due to the problems of moisture loss and secondary damage during dressing changes, the clinical application of adhesive hydrogel dressing remains a significant challenge. Herein, we developed a water-retaining and separable adhesive hydrogel wound dressing composed of methacrylated silk fibroin (SFMA), tannic acid (TA), and urethane diacrylate (UDA). The addition of TA with an abundance of catechol groups endowed the hydrogel with improved mechanical properties, good tissue adhesion and hemostasis abilities. Then, a hydrophobic polyurethane diacrylate (PUA) coating encapsulated the hydrogel by UDA polymerization, which could maintain the long-lasting high water content of the hydrogel. Furthermore, due to the adhesion energy being higher than the fracture energy of the hydrogel, it could be separated upon peeling. Finally, the animal experiments indicated that this adhesive hemostatic hydrogel could increase wound healing efficiency by maintaining long-lasting moist environment and being changed without secondary damage. These results showed that the multifunctional hydrogel might be a promising wound dressing for clinical application.