Dual Photoluminescence Emission Carbon Dots for Ratiometric Fluorescent GSH Sensing and Cancer Cell Recognition

We developed a facile strategy for the fabrication of dual-emission carbon nanodots (CDs) and demonstrated their applications for ratiometric glutathione (GSH) sensing and for differentiating cancer cells from normal cells. Dual-emission CDs were synthesized using a simple hydrothermal treatment of alizarin carmine as the carbon source, manifesting intriguing dual-emission behavior at 430 and 642 nm. With increasing GSH concentration, the fluorescence band at 430 nm increased gradually, whereas that at 642 nm decreased slightly. With monitoring of the intrinsic ratiometric fluorescence variation (I_430nm/I_642nm), as-prepared CDs were developed as an effective platform for ratiometric fluorescent GSH sensing, with a linear range of 1-10 to 25-150 μM and a detection limit of 0.26 μM. More importantly, confocal fluorescent imaging of cancer cells and normal cells indicated that obtained CDs could be implemented as an effective tool to visualize cancer cells with overexpressing GSH.