Study On Synthesis And Application Of Bio-Adhesive Catechol-modified Chitosan Hydrogel Wound Dressings

Uncontrollable bleeding and wound infection occur at the time of clinical surgery and can easily cause fatal threats to patients.Compared with traditional surgical sutures and mechanical fixation,medical adhesives are an inevitable product of the development of the era due to their advantages such as easy operation and immediate and effective.However,the current commercialized medical adhesives still have defects that cannot be ignored such as poor biocompatibility and weak dynamic wet adhesion.In response to these concerns,herein,a mussel inspired biomimetic chitosan-based hydrogel was fabricated by glow discharge electrolysis plasma(GDEP)technique for the first time,and its application as a wound dressing was explored.The main findings are as follows:1.Inspired by mussel adhesive proteins,chitosan-gallic acid(CS-GA)graft copolymers were prepared by the GDEP technique,and controllable grafting was achieved by optimizing the reaction conditions.The structure of CS-GA with three different grafting amounts was characterized by UV,1H NMR,FT-IR.Through DPPH radical scavenging,reducing power experiment,and cyclic voltammetry,CS-GA was proved to be an antioxidant material with electrical activity.Its antioxidant activity was mainly attributed to gallic acid,which showed a high dependence on the grafting amount and concentration of gallic acid.2.Under neutral conditions,CS-GA could be cross-linked by Michael addition or Schiff base reaction to form a hydrogel due to its oxygen responsiveness.CS-GA hydrogel was confirmed to have good self-healing and dynamic wet adhesion.The rheological properties indicated that the inside of the hydrogel was a stable cross-linked three-dimensional network structure,and the bioadhesive strength of the hydrogel was measured by the lap shear test.The results showed that the higher the degree of grafting of gallic acid,the better the mechanical properties and adhesive strength of the hydrogel.3.The cytocompatibility of CS-GA hydrogel was confirmed by in vitro cell experiments.Bacterial assays showed that the hydrogel had significant inhibitory effects on both Escherichia coli and Staphylococcus aureus through membrane damage mechanism,and the inhibitory effect was enhanced with the increase of GA grafting amount.Finally,the dorsal full-thickness skin defect model and liver hemorrhage model of SD rats were constructed to verify that this hydrogel had the ability to promote wound healing and rapid hemostasis,respectively.