Optimized Self-Healing and Antioxidant Hydrogels Based on Gallic Acid-Blended Quaternized Chitosan and Oxidized...

Injectable self-healing hydrogels represent promising wound dressing materials due to their conformability and minimally invasive application. This study investigated gallic acid (GA)-loaded hydrogels prepared through physical blending of quaternized chitosan (QCS) with GA, followed by mixing with oxidized pectin (OPEC) for crosslinking. The gelation time increased from 34 s to 477 s with increasing GA content while maintaining the gel fraction > 70%. However, the self-healing time decreased dramatically from 252 s to 19 s with increasing GA content. Hydrogel swelling and degradation kinetics revealed an initial loss of non-crosslinked components followed by advantageous slow surface erosion. The adhesive strength (0.74-1.48 kPa) remained clinically acceptable for all hydrogels. Rheological analysis revealed a decrease in gel strength with increasing GA content. In addition, the compressive strength decreased from 109 to 42 kPa with increasing GA content. The biological evaluation demonstrated good antioxidant activity, excellent cytocompatibility with HDFa cells, exceptional antibacterial activity (> 98% reduction against S. aureus and E. coli, with the highest efficacy in H-0.3GA), and enhanced in vitro wound closure with the addition of GA. Therefore, physical blending provides a straightforward approach for incorporating bioactive polyphenols into chitosan-based hydrogels, offering enhanced therapeutic properties through concentration-dependent mechanisms while maintaining the essential characteristics of wound dressings.