A self-crosslinked aminated silk fibroin/oxidized alginate hybrid hydrogel as a wet-tissue adhesive wound matrix

Innovative hydrogel dressings have emerged as promising materials for applications in wet tissue environments; however, achieving reliable adhesion under moist conditions remains a major challenge. In this study, a novel hybrid hydrogel was developed based on amine-modified silk fibroin (ASF) and oxidized alginate (OA), which enhanced adhesive properties through self-covalent crosslinking. ASF was prepared through chemical modification to increase reactive primary amine groups, thereby enabling effective covalent crosslinking with OA. The successful modification of ASF and OA was confirmed by FTIR, ¹H NMR, zeta potential analyses, and quantitative functional group assays. Several hydrogel formulations were screened, finding that the optimized hydrogels were evaluated. The optimized ASF/OA hydrogel (4:1 ratio, 4% total solid content) exhibited strong adhesion to highly moist incision wounds on ex vivo chicken skin for up to 24 h, and achieved an adhesive strength of 9.0 ± 1.0 kPa on ex vivo porcine skin, which is comparable to that of commercial fibrin glue. In addition, the ASF/OA hydrogel exhibited a porous structure, favorable swelling behavior, controlled degradation rate, and in vitro biocompatibility with L929 fibroblast cells. These findings suggest that the ASF/OA hydrogel serves as a biocompatible adhesive matrix with effective wet-tissue adhesion under ex vivo conditions, indicating its potential for further development as a biomacromolecular material platform for wet wound environments. Moreover, this study introduces a novel strategy for tuning the primary amine content of ASF through functionalization, which enhances its physicochemical properties and supports its applicability in the development of advanced silk-based biomaterials.