▎ 摘　　要

We build a novel fluorescence resonance energy transfer (FRET) method based on N-doped graphene quantum dots (NGQDs)-MnO2 nanocomposite for rapid, sensitive detection of glutathione (G SH) levels in human serum. In this strategy, MnO2 nanosheets on the NGQDs surface serve as a quencher. NGQDs fluorescence can make a recovery by the addition of GSH, which can reduce MnO2 to Mn2+, and thus the GSH can be monitored. The MnO2 platform affords minimal background and high sensitivity for detecting GSH in this proposed scheme. Meanwhile, relevant fluorescence on-off-on processes were monitored, and the sensing mechanism was explored.