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, biode-gradability 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 degrees 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 character-istics of injectability, fast gelation, bioadhesion and biocompatibility, with great potential for application in biomedical fields.