Mussel‐mimetic chitosan based injectable hydrogel with fast-crosslinking and water-resistance as tissue adhesive

It is very crucial to develop ideal tissue adhesive materials with high toughness, super tissue adhesion, biodegradability and biocompatibility for the treatment of accidental trauma and surgery. Inspired by mussels, a novel injectable bioadhesive chitosan-based hydrogel was developed by dual-ionic crosslinking in this paper, which was composed of catechol-modified chitosan (Cat-CS), thermosensitive polymer (PNAM) and NaHCO3. The gelation time of Cat–CS–PNAM/NaHCO3 hydrogel is 50 s at 37 °C, showing good sol-gel transition under different temperatures. The prepared hydrogels have the ability to adhere to a variety of materials surface, wherein the adhesion strength to metal surface is 126.20 ± 15.17 kPa. They also possess compact microstructure and excellent dry/wet adhesion to tissues due to the interaction between catechol/amino groups and tissues, combined with physical crosslinking. In addition, the hydrogels can be completely degraded after 14 days in vitro and show good cytocompatibility. This newly designed mussel-inspired chitosan hydrogels have the characteristics of injectability, fast gelation, bioadhesion and biocompatibility, with great potential for application in biomedical fields.