Progress and Perspective on Carbon-Based Nanozymes for Peroxidase-like Applications

Tumor microenvironment-responsive chemodynamic therapy (CDT), an approach based on Fenton/Fenton-like reaction to convert hydrogen peroxide (H₂O₂) into the highly cytotoxic hydroxyl radical (·OH) in situ to kill cancer cells, represents an important direction for cancer therapy. Different types of nanozymes (nanomaterial-based catalysts that can mimic the activities of natural enzymes) have been developed to mimic peroxidase. This Perspective highlights the latest research progress regarding low-cost and biocompatible carbon-based nanozymes for peroxidase mimics. The effects of structure and surface properties of carbon-based nanozymes on their electronic transfer and peroxidase-like activity are analyzed, including nanospheres, nanotubes, nanosheets, and graphene quantum dots (GQDs) with or without surface functionalization and heteroatom doping. We expand our newly developed carbon nitride (g-C₃N₄) QD systems to nanozyme application, which are highly efficient in converting the intracellular H₂O₂ to ·OH species to kill 4T1 cancer cells and demonstrate a great potential for CDT.