An ultrasensitive MnO2-S,O-doped g-C3N4 nanoprobe for “turn-on” detection of glutathione and cell imaging

Abstract The utilization of nanomaterial-based probes in detecting glutathione (GSH) and cell imaging has aroused extensive attention owing to the excellent properties of nanoprobes. Herein, we have synthesized manganese dioxide-S, O co-doped graphitic carbon nitride quantum dots (MnO 2 -S, O-CNQDs) nanocomposite by in situ synthesis of MnO 2 nanosheets in S,O-CNQDs dispersion solution. It was found that GSH could specifically bind to MnO 2 -S, O-CNQDs so that the fluorescence of S, O-CNQDs could be recovered. As such, a “turn-on” MnO 2 -S, O-CNQDs nanoprobe can be fabricated and applied to rapidly determine trace amounts of GSH. Under the optimal conditions, MnO 2 -S, O-CNQDs shows sensitive response to GSH in the range 10–270 μM with a detection limit of 0.307 μM ( S / N  = 3). The developed MnO 2 -S, O-CNQDs probe has demonstrated great potential to detection of GSH in biological samples and glutathione injections. What is more, MTT assay indicates that MnO 2 -S, O-CNQDs has low biotoxicity. The non-fluorescence MnO 2 -S, O-CNQDs reacts with GSH to recover the fluorescence of S, O-CNQDs in HepG2 cells. Thus, the “turn-on” fluorescence change of MnO 2 -S, O-CNQDs offers a potentially useful tool to monitor GSH of cancer cells. Graphical Abstract