pH-Responsive multifunction antibacterial hydrogel with remodeling the wound microenvironment for treating diabetic wound.

Oxidative stress and chronic inflammation are major obstacles for diabetic wounds. Therefore, synergistically scavenging excess reactive oxygen species (ROS) and inhibiting inflammatory reaction is a promising strategy to treat diabetic wounds. In the course of this work, a pH-responsive multipurpose hydrogel (CMCS/2-FPBA/TA-Fe) was fabricated for the first time, which consisted of trivalent iron ions (Fe3+), carboxymethyl chitosan (CMCS), tannic acid (TA), and 2-formylphenylboronic acid (2-FPBA). The results showed that CMCS/2-FPBA/TA-Fe hydrogel displayed excellent mechanical stability, rapid self-healing capability, together with pH-responsive drug release behavior. Antibacterial studies demonstrated that CMCS/2-FPBA/TA-Fe hydrogel exhibited good inhibitory effect against both Staphylococcus aureus and Escherichia coli. A full-thickness skin defect model against diabetic mice, CMCS/2-FPBA/TA-Fe hydrogel could significantly suppress inflammatory response, stimulate angiogenesis, facilitate collagen deposition, accelerate the transformation of M1-type macrophages to M2-type macrophages, boosting wound repair. This promising design provided a new strategy and insight for managing diabetes-related chronic ulcers.