Facile Synthesis of Janus Hydrogel for the Treatment of Abdominal Wall Defects by Solvent Evaporation

Janus adhesive hydrogels exhibit broad prospects in biomedical fields such as tissue repair, anti-adhesion, hemostasis, and human activity sensing. However, a simple fabrication process for Janus hydrogels remains lacking, which limits their clinical translation. To address the above issue, this study proposes an innovative fabrication strategy based on solvent evaporation-induced interfacial self-assembly: solvent evaporation drives the spontaneous aggregation of polyvinyl alcohol (PVA) at the water-air interface; then, combined with free radical polymerization of acrylamide (AM)/isocyanoethyl methacrylate-arginine (IEM-Arg) and freeze-thaw treatment, Janus hydrogels are constructed in one step. There is a significant difference in adhesive strength between the two sides of this Janus hydrogel; after adding polydopamine-coated reduced graphene oxide (rGO@PDA), the adhesive strength of the bottom side is ten times that of the top side. In this study, the mechanism underlying the asymmetric adhesion of the hydrogel is investigated using techniques such as X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). In terms of biomedical applications, when this Janus hydrogel is used as a biomedical patch in an abdominal wall defect model, the results showed that it can effectively inhibit the formation of tissue adhesions and promote soft tissue regeneration.