Adaptive Hydrogels Based on Nanozyme with Dual-Enhanced Triple Enzyme-Like Activities for Wound Disinfection and Mimicking Antioxidant Defense System.

Bacterial infection and oxidative stress are two critical problems for chronic infected wound healing. Here, molybdenum disulfide nanosheets (MoS2 NSs) with triple enzyme-like activities are loaded onto carbon nanotubes (CNTs) and incorporated into multifunctional hydrogels aiming to eradicate bacteria and eliminate free radicals. The nanozyme activities of MoS2 are significantly enhanced through CNTs and near-infrared irradiation. The hydrogel exhibits significant antibacterial performance attributed to the peroxidase-like activity (catalyzing hydrogen peroxide (H2 O2 ) into hydroxyl free radicals (•OH)) under acidic conditions, glutathione loss, and photothermal therapy. Additionally, the nanozyme can mimic the superoxide-like activity to transform the superoxide radicals (O2 •- ) into H2 O2 and oxygen (O2 ), then H2 O2 is further depleted into O2 via the catalase-like activity, benefitting from which and •OH scavenging ability, the hydrogel shows excellent scavenging free radical ability in neutral environment and provides abundant O2 for wound healing. The multifunctional hydrogel, crosslinked by dynamic boron ester bonds, exhibits adhesiveness, self-healing, and shape-adaptivity, which can fill the cavity of irregular wounds and promote the nanozyme to play the role with maximum efficiency. The hydrogels notably accelerate the skin reconstruction through killing bacteria, clearing ROS, promoting collagen deposition and angiogenesis.