A paintable composite hydrogel patch for potential wound dressings

Hydrogel has incomparable advantages in promoting chronic wound healing due to its high-water content, softness and excellent physiological activity. However, as a treatment platform, most hydrogel dressings are fixed at the wound site in block form, which is difficult to fully contact and fit with the tissue, limiting their efficacy. Here, a composite hydrogel that can be conveniently painted to material surface and closely adhered is developed. The hydrogel is obtained through a double network strategy and multiple non-covalent interactions between N-(3,4-dihydroxyphenylethyl) acrylamide (NA)-acrylic acid-acrylamide terpolymer, nano Fe3O4 and chitosan. NA monomer with catechol-like structure can significantly improve the adhesion strength of the hydrogel to 25.06 kPa, which is superior to the commercially available fibrin glue (∼11.5 kPa). Notably, the high-efficiency paintability of the hydrogel can be achieved just by the initiation of ultra-trace potassium persulfate. The hydrogel patch also exhibits satisfactory mechanical properties and cytocompatibility. Hence, this multifunctional hydrogel will be conveniently painted to the wound bed as a patch without adverse liquid leakage, providing an optimistic material for chronic wound treatment.