Silk Fibroin Nanozyme Hydrogel with Self-Supplied H₂O₂ for Enhanced Antibacterial Therapy

Peroxidase-mimicking nanozyme therapy has emerged as a powerful tool in antibacterial therapy. Due to the critical role in reactive oxygen species (ROS) generation, various in situ H 2 O 2 supplying nanoagents have been developed to guarantee the therapeutic effect. However, the challenges in reliance on external stimulus, instability of the H 2 O 2 donor, and risk of leakage limited their antibacterial efficiency and actual application. In this work, we fabricated an injectable silk fibroin/ZnO NP/mica–Fe 3 O 4 (SFZM) composite nanozyme hydrogel with spontaneous H 2 O 2 generation and peroxidase-mimicking nanozyme properties. The ZnO NPs could produce H 2 O 2 without light or other external stimulus. Under a weak acid environment, the H 2 O 2 produced from ZnO NPs could be in situ transformed to ROS by magnetic mica–Fe 3 O 4 nanosheets, leading to nearly 50% enhancement in antibacterial activity compared with a silk fibroin–ZnO hydrogel. Meanwhile, the SFZM nanozyme hydrogel displayed in vivo adhesion and hemostasis properties. As a result, the SFZM hydrogel could accelerate the healing of bacteria-infected wounds in rats. More interestingly, the ZnO exhibited continued H 2 O 2 generation during at least 12 days, suggesting the long-term enhanced antibacterial effect of the SFZM hydrogel. Also, the SFZM nanozyme hydrogel showed low nanomaterial leakage and demonstrated biocompatibility both in vitro and in vivo .