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

Abstract

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.