Allantoin-functionalized silk fibroin/sodium alginate transparent scaffold for cutaneous wound healing

In clinical application, it's highly desirable for developing bio-functionalized cutaneous scaffold with transparent features for convenient observation, excellent biocompatibility, and high efficiency for promoting wound repair. Herein, allantoin-functionalized composite hydrogel was developed by coupling silk fibroin (SF) and sodium alginate (SA) for treatment of cutaneous wounds. The prepared allantoin-functionalized SF-SA composite scaffolds (AFAS) exhibited excellent mechanical properties, especially featured by similar ultimate tensile strength (UTS) and elongation at breaking to human skin. Besides, the solvent-casting method guaranteed the AFAS to obtain highly transparent properties with sufficient moisture permeability and excellent adhesion in wet state. In vitro cellular experiments demonstrated excellent biocompatibility of the scaffold that attachment and proliferation of NIH-3T3 fibroblast cells was promoted in the presence of AFAS. Furthermore, the scaffolds exhibited efficient hemostatic property, based on rat hepatic hemorrhage model. In a cutaneous excisional mouse wound model, the AFAS significantly improved the wound closure rate, compared with pure SF-SA scaffolds and blank control. Moreover, the histomorphological assessments showed that AFAS facilitated the integrity of skin and wound healing process by enhancing collagen deposition, re-epithelialization and vascularization at wound site. The results demonstrate that the novel allantoin-functionalized SF/SA transparent hydrogel has great potential for clinical treatment of cutaneous wound.