Pyrogallol-modified Gelatin Hydrogel Adhesives For Infected Skin Regeneration

The nature-inspired tissue adhesives that are used as tissue sealants or wound dressings for reconstruction of damaged tissues,have promising prospects in the field of biomedicine.However,weak adhesion,complicated pre-synthesis steps,multicomponent systems,and prohibitive costs impede their applications.Inspired by the adhesion and fast regenerative ability of tunicates,a sprayble pyrogallol-modified gelatin adhesive hydrogel was constructed as an antibacterial dressing to promote wound healing.After a simple mixing of gelatin-FeCl₃ with2,3,4-trihydroxybenzaldehyde（THB）solution,the pyrogallol moieties in THB were conjugated to the molecular chain of gelatin through Schiff base reaction;meanwhile,the hexavalent Fe complexes were formed due to the chelation with a small amount of Fe³⁺,which contributed to the crosslinking network of pyrogallol-gelatin.The resulting hydrogels（termed as GelTHB-Fe）exhibited not only tunable gelation time,mechanical strength and self-healing ability by adjusting the composition,but also a robust adhesion to a variety of materials,with an average adhesion strength of 136.7k Pa,147.3 k Pa,153.7 k Pa,92.9 k Pa,and 56.5 k Pa to PMMA,iron,ceramic,glass and pigskin,respectively.Intriguingly,the pyrogallol moieties imparted an antibacterial activity to the GelTHB-Fe hydrogel,which was shown to reduce infection and promote wound healing in a diabetic rat model.This GelTHB-Fe hydrogel holds great potential as a promising tissue adhesive.