Tempo‐Functionalized Janus Hydrogel Crosslinked by Tandem Dynamic Covalent Bonds for Internal Organ Injury Repair and Deep Second‐Degree Burn Wound Healing

Abstract Wound dressings with asymmetrical adhesion performances and biological activity are urgently needed for the treatment of tissue/organ injuries. Herein, an antioxidative and Janus hydrogel (Tempo‐FPF) composed of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl functionalized poly(ethylene imine) (PEI‐Tempo), 2‐formylphenylboronic acid (2‐FPBA) and poly(vinyl alcohol) (PVA) is developed based on tandem dynamic iminoboronate and boronate ester bonds. The addition of PEI and 2‐FPBA onto the top of the precursor hydrogel formed by PEI‐Tempo, 2‐FPBA, and PVA can endow the Tempo‐FPF hydrogel with asymmetric adhesion properties owing to the differences in crosslinking density and hydrophilicity between the two sides. Moreover, profiting from Tempo functionalization, the Tempo‐FPF hydrogel exhibits outstanding free radical scavenging ability. In vivo outcomes of gastric perforation and liver incision treatments in rats reveal that the Tempo‐FPF hydrogel can not only enable firm injury site sealing to inhibit gastric acid leakage and bleeding but also prevent the occurrence of tissue/organ adhesion. In vivo deep second‐degree burn wound study demonstrates that the Tempo‐FPF hydrogel can attenuate oxidative stress‐induced inflammation response within the wound site to accelerate the reconstruction of skin tissues. This work provides a promising strategy for the design of potent antioxidative hydrogel dressings with on‐demand adhesion behaviors for in vivo tissue/organ injury repair.