▎ 摘　　要

The current study reports the design and construction of enzyme-free sensor using N-doped graphene quantum dots (N-GQDs)-decorated tin sulfide nanosheets (SnS2) for in situ monitoring of H2O2 secreted by human breast cancer cells. N-GQDs nanoparticles having a size of less than 1 nm were incorporated into SnS2 nanosheets to form an N-GQDs@SnS2 nanocomposite using a simple hydrothermal approach. The resulting hybrid material was an excellent electrocatalyst for the reduction of H2O2, owing to the combined properties of highly conductive N-GQDs and SnS2 nanosheets. The N-GQDs@SnS2-based sensing platform demonstrated substantial sensing ability, with a detection range of 0.0125-1128 mu M and a limit of detection of 0.009 mu M (S/N = 3). The sensing per-formance of N-GQDs@SnS2 was highly stable, selective, and reproducible. The practical application of the N-GQDs@SnS2 sensor was successfully demonstrated by quantifying H2O2 in lens cleaner, human urine, and saliva samples. Finally, the N-GQDs@SnS2 electrode was successfully applied for the real-time monitoring of H2O2 released from breast cancer cells and mouse fibroblasts. This study paves the way to designing efficient non -enzymatic electrochemical sensors for various biomolecule detection using a simple method.