Chronological adaptive polyoxometalate-based hydrogel for diabetic chronic wounds through synchronous bacterial ferroptosis death and immunomodulation

Abstract

Chronic wounds are a serious complication for diabetic patients, causing substantial inconvenience and significant economic burden to patients, due to their characteristics of sequential development encountering bacterial infections, excessive reactive oxygen species (ROS)-induced inflammation and M1 macrophage accumulation. Herein, we developed a chronological adaptive Fe-based polyoxometalate on hyaluronic acid (Fe-POM@HA) hydrogel for diabetic chronic wounds, whose capacity can be strengthened by synergistic the acid-activated and glutathione-enhanced NIR-II photothermal therapy and achieving spatiotemporal selective and adaptive inhibition of bacterial infection. During the bacteria-infection slightly acidic stage, Fe-POM catalyzes endogenous H2O2 for ROS generation inducing bacterial ferroptosis, suppressing glutathione peroxidase activity, and promoting lipid peroxidation to disrupt the bacterial biofilm. As the wound transitions to neutral inflammation stage, Fe-POM with Fe2+/Mo5+ mixed valences can simultaneously alleviate oxidative stress and overcome the hypoxia microenvironment by continuously scavenging excessive ROS for endogenous H2O2 cyclic accumulation and O2 sustainable replenishment. Importantly, the Fe-POM@HA hydrogel could further promote wound angiogenesis at the new tissue proliferation stage through the immunomodulation of macrophage polarization and inflammatory factor expression. Therefore, Fe-POM@HA hydrogel provides a promising chronologically adaptive protocol for the repair and regeneration of chronic cutaneous wounds addressing complex clinical demands.