Osteichthyes skin-inspired tough and sticky composite hydrogels for dynamic adhesive dressings

Development of biomimetic hydrogel-based wound dressing is highly desirable for addressing life-threatening infectious skin injuries but has proved to be extremely challenging. However, poor tissue adhesive performance, stretchability and difficult fixation lead to conventional wound dressings failing to adapt to dynamic wounds with high-frequency movement or special fluctuant positions. Herein, we present a new biomimetic natural-synthetical combination by integrating Osteichthyes-extracted gelatins into hydrophilic polymeric networks to form unique tough, adhesive, self-healable composite hydrogels. The resultant Gelatin/PHEAA hydrogel without any growth factors/fungicides has high mechanical strength (∼1.0 MPa), high interfacial toughness (>1000 J/m2), and remarkable antifouling activity, enabling the hydrogel to effectively inhibit bacterial proliferation and promote the wound healing. Moreover, due to the abundant hydrogen bonds in composite crosslinked networks, the Gelatin/PHEAA hydrogels maintain high, repeatable adhesion even in high dynamic cases, regardless of wet or dry environments and the types of solid nonporous substrates. Further in vitro and in vivo full-thickness skin defect model confirms that the Osteichthyes-extracted proteins can accelerate collagen deposition and vascular regeneration, leading to a faster wound closure efficiency. Ultimately, we believe that the designed tough Gelatin/PHEAA hydrogels can be high-value candidates for managing rapid wound healing, while the proposed structural biomimetic combination can inspire researchers to design more interesting and effective biomaterials for clinical translation and health care.