A Hydrogen-Bonded Extracellular Matrix-Mimicking Bactericidal Hydrogel with Radical Scavenging and Hemostatic Function for pH-Responsive Wound Healing Acceleration

Generation of reactive oxygen species, delayed blood clotting, prolonged inflammation, bacterial infection, and slow cell proliferation are the main challenges of effective wound repair. Herein, a multifunctional extracellular matrix-mimicking hydrogel is fabricated through abundant hydrogen bonding among the functional groups of gelatin and tannic acid (TA) as a green chemistry approach. The hydrogel shows adjustable physicochemical properties by altering the concentration of TA and it represents high safety features both in vitro and in vivo on fibroblasts, red blood cells, and mice organs. In addition to the merit of facile encapsulation of cell proliferation-inducing hydrophilic drugs, accelerated healing of skin injury is obtained through pH-dependent release of TA and its multifaceted mechanisms as an antibacterial, antioxidant, hemostatic, and anti-inflammatory moiety. The developed gelatin-TA (GelTA) hydrogel also shows an outstanding effect on the formation of extracellular matrix and wound closure in vivo via offered cell adhesion sites in the backbone of gelatin that provide increased re-epithelialization and better collagen deposition. These results suggest that the multifunctional GelTA hydrogel is a promising candidate for the clinical treatment of full-thickness wounds and further development of wound dressing materials that releases active agents in the neutral or slightly basic environment of infected nonhealing wounds.