Biocompatibility nanoprobe of MXene N-Ti3C2 quantum dot/Fe3+ for detection and fluorescence imaging of glutathione in living cells

MXene quantum dots have attracted much attention due to their great optical performance and excellent water solubility. Glutathione (GSH) plays a key role in living cells. In this study, a biocompatibility nanoprobe was prepared for detecting intracellular GSH based on MXene N-Ti3C2 quantum dots (N-Ti3C2 QDs). The N-Ti3C2 QDs act as the fluorescence reporters and the ferric iron (Fe3+) as the quenchers based on nonradiative electron-hole annihilation. When Fe3+ encounters the amino group of N-Ti3C2 QDs, the electrons of N-Ti3C2 QDs in the excited state will transfer to the half-filled 3d orbitals of Fe3+, leading to the fluorescence quenching of N-Ti3C2 QDs. When the N-Ti3C2 QDs/Fe3+ nanoprobe acts on the cancer cell MCF-7, the abundant GSH in the cancer cells can reduce Fe3+ to Fe2+, which will restore the fluorescence of N-Ti3C2 QDs. The N-Ti3C2 QDs/Fe3+ nanoprobe displays a high sensitivity for GSH with a detection limit of 0.17 μM in range of 0.5−100 μM. It becomes a promising probe for detecting and showing cellular imaging of GSH in MCF-7 cells. The N-Ti3C2 QDs/Fe3+ nanoprobe might provide a new way for imaging-guided precision cancer diagnosis.