Reactive Oxygen-Correlated Photothermal Imaging of Smart COF Nanoreactors for Monitoring Chemodynamic Sterilization and Promoting Wound Healing.

Chemodynamic therapy (CDT) has emerged as a promising approach for treating infected diabetic wounds, while reliable imaging technology for simultaneous monitoring of ROS and therapeutic processes is still a formidable challenge. Herein, smart covalent organic framework (COF) nanoreactors (COF NRs) are constructed by hyaluronic acid (HA) packaged glucose oxidase (GOx) covalently linked Fe-COF for diabetic wound healing. Upon the breakdown of the HA protective layer, GOx consumes glucose to produce gluconic acid and hydrogen peroxide (H 2 O 2 ), resulting in decreased local pH and H 2 O 2 supplementation. Density functional theory (DFT) calculations show that Fe-COF has high catalytic activity towards H 2 O 2 , leading to in situ generation of hydroxyl radicals (·OH) for sterilization, and the localized downregulation of glucose effectively improved the microenvironment of diabetic wounds. Meanwhile, based on the near-infrared photothermal imaging of oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB), the authors showed that TMB can be applied for the point-of-care testing of ·OH and glucose, and assessing the sterilization progress in vivo. More significantly, the facile photothermal signaling strategy can be extended to monitor various ROS-mediated therapeutic systems, enabling accurate prediction of treatment outcomes.