A non-enzymatic, biocompatible electrochemical sensor based on N-doped graphene quantum dot-incorporated SnS nanosheets for in situ monitoring of hydrogen peroxide in breast cancer cells.

The current study reports the design and construction of enzyme-free sensor using N-doped graphene quantum dots (N-GQDs)-decorated tin sulfide nanosheets (SnS) for in situ monitoring of HO secreted by human breast cancer cells. N-GQDs nanoparticles having a size of less than 1 nm were incorporated into SnS nanosheets to form an N-GQDs@SnS nanocomposite using a simple hydrothermal approach. The resulting hybrid material was an excellent electrocatalyst for the reduction of HO, owing to the combined properties of highly conductive N-GQDs and SnS nanosheets. The N-GQDs@SnS-based sensing platform demonstrated substantial sensing ability, with a detection range of 0.0125-1128 µM and a limit of detection of 0.009 µM (S/N = 3). The sensing performance of N-GQDs@SnS was highly stable, selective, and reproducible. The practical application of the N-GQDs@SnS sensor was successfully demonstrated by quantifying HO in lens cleaner, human urine, and saliva samples. Finally, the N-GQDs@SnS electrode was successfully applied for the real-time monitoring of HO 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.