Tunichrome-inspired pyrogallol functionalized chitosan for tissue adhesion and hemostasis.

The nature-inspired fabrication of tissue adhesive and hemostatic hydrogels holds great potential for restoring damaged internal tissue in regenerative medicine. However, feeble adhesion, multifaceted systems, prohibitive costs, and toxicity impede their applications in the medical field. In order to solve this problem, we fabricated chitosan-based wet tissue adhesive with hemostatic functions inspired by the self-healing mechanism of the tunicate. In order to introduce pyrogallol moiety, gallic acids, which are broadly distributed in nature, were incorporated into chitosan backbone, a key residue for the self-healing process of tunichrome in tunicates. The in vitro adhesion test results of the tunicate-inspired hydrogel exhibited two-fold greater adhesion ability in wet condition than did fibrin glue, a commercially available surgical glue. Further, the tunicate-inspired hydrogel exhibited significantly more platelet adhesion and blood clotting ability than the parent polymer. We also demonstrated the ability of the derivative to completely mimic the tunicate's fibrous structure by fabricating an electrospun mat. The hemostatic function vis-à-vis the wet adhesiveness of the synthesized chitosan-based material may be useful for facilitating the shortcomings of the restorative tissue medicine. Additionally, the electrospinning capability will enable the modulate of the structure-property relationship and a three-dimensional design for its application site.