Self-assembled copper herbal carbon dots nanosheets with powerful antibacterial properties: A robust cascade antioxidant nanozyme for scavenging reactive oxygen species

Oxidative stress is a growing concern, necessitating more effective antioxidants for complex environments. Herein, we developed a composite nanozyme, DVI-CDs-Cu, with exceptional antioxidant and antibacterial properties by utilizing DVI-CDs derived from Chinese herbs: Dandelion, Violet, and Isatis root, complexed with Cu2+ ions. The DVI-CDs with abundant surface functional groups exhibited excellent superoxide dismutase-like (SOD-like) activity while forming stable complexes with copper ions. The attached copper ions performed the peroxidase-like (POD-like) function and formed a cascade effect, greatly enhancing the antioxidant capacity of the DVI-CDs-Cu nanozyme and strengthening its antibacterial property. The nanozyme was able to comprehensively clear 90 % of reactive oxygen species (ROS) while killing approximately 98 % of bacteria. The potential application of the nanozyme as a ROS scavenger was demonstrated by exploring its application to cigarette filters, capable of eliminating approximately 80 % of ROS. This provides a new case for the design and development of CDs-metal ions synergistic bionano-enzymes.