Facile Preparation of Tunicate-Inspired Chitosan Hydrogel Adhesive with Self-Healing and Antibacterial Properties

In order to replace traditional wound treatments such as sutures, tissue adhesives with strong wet tissue adhesion and biocompatibility have attracted more attention to the applications of non-invasive wound closure. Herein, inspired by tunicate adhesive protein, a series of 2,3,4-trihydroxybenzaldehyde (TBA)-modified chitosan hydrogels (CS-TBA-Fe) were prepared by easily mixing the solutions of chitosan-FeCl₃ and TBA via the Schiff-base reaction and the coordination between Fe³⁺ and pyrogallol groups. The gelation time was greatly shortened to only several seconds after induced even trace Fe³⁺. The hydrogel (CS-TBA-Fe) exhibited ~12-fold enhanced wet tissue adhesion strength (60.3 kPa) over the commercial fibrin glue. Meanwhile, the hydrogel also showed robust adhesion to various substrates such as wood, PMMA, and aluminum. The swelling ratio and rheological property can be simply controlled by changing the concentrations of chitosan, TBA, and Fe³⁺. Moreover, the hydrogel displayed a rapid and highly efficient self-healing ability and an excellent antibacterial activity against E. coli. The overall results show that the CS-TBA-Fe hydrogel with enhanced wet adhesiveness will be a promising tissue adhesive material.