Bio-adhesive catechol-modified chitosan wound healing hydrogel dressings through glow discharge plasma technique

•A new strategy for polysaccharide grafted phenolic acids - Glow Discharge Plasma.•High performance dynamic wet adhesion hydrogels.•Bioactive natural macromolecular hydrogels - antibacterial and antioxidant properties.•Multifunctional biomedical adhesive - promoting wound healing and hemostasis. For clinical traumas and surgeries, adhesives that can be used in humid environments is considerably challenging. Inspired by the adhesive proteins of mussel, a gallic acid-modified chitosan-based (CS-GA) hydrogel was prepared through discharge plasma technology, which was first reported to realise polysaccharide-macromolecule-grafted phenolic acids. CS-GA hydrogels with different grafting amounts were successfully prepared, and their structures were characterised using ultraviolet, 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The modified material exhibited excellent antioxidant properties, which were verified using classical DPPH radical scavenging and reducibility experiments. CS-GA was oxidised in air under physiological conditions and cross-linked to form a hydrogel, with unusual toughness and adhesion properties. The high biocompatibility and haemocompatibility of this hydrogel were showed through cytotoxicity and haemolysis experiments. Furthermore, the abilities of the hydrogel to promote wound healing and haemostasis were evaluated using in vivo rat whole layer skin defect and liver haemorrhage models, respectively. These abilities can provide many possibilities for the development of multifunctional biomedical adhesives.