Multifunctional injectable self-healing hydrogels based on quaternized chitosan-gallic acid and oxidized pectin for...

Wound dressing materials that possess injectability, tissue adhesion, and self-healing abilities, with the added advantage of therapeutic potential, are highly desired in medicine. This research used quaternized chitosan incorporating gallic acid (QCS-GA), prepared by a so-called grafting method, which resulted in GA incorporation mainly through ionic interactions, as evidenced by detailed chemical characterization, including 2D DOSY NMR and XPS. QCS-GA, in combination with oxidized pectin (OPEC), was used to synthesize hydrogels with three different GA contents. These hydrogels were crosslinked by dynamic reversible covalent bonds and ionic bonds between QCS-GA and OPEC, providing the hydrogels with injectable, adhesiveness, self-healing properties, and gel fractions from 88 to 97%. Despite the lack of grafting, the pretreatment of QCS and GA with hydrogen peroxide and ascorbic acid resulted in superior hydrogel properties that could not be reproduced using physical mixtures of QCS and GA. An increase in GA content in the hydrogels decreased the gelation time, reduced the degradation rate, and enhanced in vitro antioxidant activity. The hydrogel with the highest GA content displayed broad-spectrum in vitro antibacterial ability due to the intrinsic antibacterial properties of GA and QCS, as well as excellent in vitro cytocompatibility and cell migration. Therefore, this hydrogel can be a multifunctional injectable self-healing hydrogel with potential as a wound dressing.