Quaternized chitosan-based biomimetic nanozyme hydrogels with ROS scavenging, oxygen generating, and antibacterial capabilities for diabetic wound repair.

Management of chronic diabetic wounds is challenging due to excess reactive oxygen species (ROS), hypoxia, persistent inflammation, and bacterial infection within the wound microenvironment. For addressing the aforementioned concern, we have developed a multifunctional hydrogel dressing (PMT-C@PhM) based on chitosan with self-healing, adhesive, antibacterial, and antioxidant capacities for therapeutic diabetic wounds. The hydrogel dressing consisted of quaternary ammonium salt- and catechol- modified chitosan (CQCS), thioctic acid-functionalized poly(ethylene glycol)s (PEGs), and polydopamine-coated honeycomb manganese dioxide nanoparticles (hMnO2@PDA NPs). The nanozyme-modified hydrogel exhibits superoxide dismutase (SOD) and catalase (CAT) activities to scavenge ROS while generating oxygen to alleviate oxidative stress and hypoxic environment in wounds, and to attenuate the inflammatory response through modulating macrophage polarization. The PMT-C@PhM hydrogel is effective in the treatment of diabetic wound infections caused by Staphylococcus aureus, and relieves oxidative stress, inhibits inflammation, and promotes neovascularization and dermal collagen synthesis thus providing favorable conditions for accelerated wound healing. In conclusion, the aforementioned approach offers a biosafe, straightforward, and efficient strategy for the management of diabetic wounds.