Ce, N, S co-doped carbon dots with synergistically enhanced peroxidase-like activity for glucose biosensing and ROS-mediated cytotoxic effect.

Engineering novel nanozymes with excellent catalytic activity and good biocompatibility, and exploring their multifunctional applications are crucial for the advancement of nanozyme science. Herein, we developed Ce, N, S co-doped carbon dots (Ce-NSCDs) via a hydrothermal method, which exhibit synergistically enhanced peroxidase-like (POD-like) activity. In this rationally designed system, the N/S-co-doped carbon matrix functions as an electron donor, enriching the electron density around the Ce species. The Ce sites, existing as a Ce3+/Ce4+ redox couple, act as the catalytic centers. This facilitated electron transfer from the matrix to Ce optimizes the redox cycling, thereby cooperatively boosting the peroxidase-like activity. Leveraging this high activity, a glucose oxidase cascade biosensing platform was constructed, achieving sensitive detection of glucose in human serum. Furthermore, the intrinsic POD-like activity of Ce-NSCDs enabled a ROS-mediated cytotoxic effect against cancer cells under H2O2 stimulation. This work not only elucidates a distinct synergistic mechanism in carbon-based nanozymes but also demonstrates their integrated potential for both sensitive biosensing and cellular catalytic applications.