Zn²⁺-Responsive Hydrogel Wound Dressing For Easy Dressing Change

A practical problem in clinic is that the dressing is inclined to adhere to wound beds and needs more than an hour to be removed,accompanying with destroying neo-epithelial tissues,re-bleeding,and deferring wound healing process.Inspired by the chemical structure of mussel adhesive protein（MAP）,an injectable dopamine（DOPA）-based adhesive hydrogel was constructed as wound healing dressing which could be easily replaced by spraying zinc ions.A hyperbranched polymer named HB-PBAE was synthesized by Michael addition reaction among dopamine（DOPA）,poly（ethylene glycol）diacrylate（PEGDA700）,and pentaerythritol triacrylate（PETA）.The DOPA-based adhesive hydrogel was fabricated by mixing HB-PBAE,poly（1-vinylimidazole）（PVI）and gelatin solution,followed by adding Fe³⁺.Hyperbranched DOPA structure crosslinked by Fe³⁺was designed to simulate the typical chemical structure of MAPs and grant the hydrogel with an excellent adhesive property,and PVI was introduced to imitate the histidine residue in MAPs and endow the hydrogel with a zinc ion response property,while Geln was used to replicate the protein of MAPs and bestow a good compatibility of the hydrogel.Ten minutes after encountering zinc ions,the adhesive strength of hydrogels decreases 64.5%and the mechanical strength increases 364.7%.Importantly,the adhesive dressing can reduce the damage during dressing change in a rat wound bed and accelerate wound healing process.The metal ion facilitating dressing change might provide a novel concept in designing wound dressing.