A mussel-inspired flexible chitosan-based bio-hydrogel as a tailored medical adhesive

The significant progress in efforts to design hydrogel adhesive mimicking mussels' functions has been witnessed in recent years. However, it is still an arduous challenge to fabricate self-adhesive hydrogel adhesive that tradeoff of exalting features containing scalability, self-healing, degradability, biocompatibility, and antibacterial properties. Herein, we manufactured a multi-functional physical hydrogel adhesive by integrating catechol groups modified chitosan and polyvinyl alcohol (PVA). Intriguingly, the physical gels reinforce durable and repeatable adhesiveness due to the limited auto-oxidation of catechol groups of the 3-(3,4-dihydroxyphenyl) propionic acid modified chitosan (DCS), which can be adhered diametrically on human skin without shedding and residue. Additionally, the dynamic H-bonds between DCS and PVA endows the hydrogel to self-heal under a relatively mild stimulation. The assembly of silver nano armor remarkably enhances the mechanical strength and antibacterial of the hydrogel. Meanwhile, the metal coordination formed between the nano-silver and the hydroxyl groups of catechol and the electrostatic interaction between the silver ions and the hydroxyl groups also contribute to the hydrogel to achieve self-healing. This work provides a neoteric prospect in designing degradable hydrogels with stretchability, self-adhesion, self-healing, antibacterial and biocompatibility for potential applications in tissue adhesion and wound healing.