Fluorescence/Colorimetric Dual-Mode Probe Based on Nitrogen, Sulfur, and Boron Codoped MXene Quantum Dots for Detection of Glutathione and Imaging in Mitochondria.

Quantifying and monitoring glutathione (GSH) in living cells is of great significance for understanding GSH-related oxidative stress disorders and neoplastic conditions. In this work, we developed nitrogen/sulfur/boron codoped MXene quantum dots (NSB-MQDs) through a facile single-pot hydrothermal synthesis strategy for fluorescence/colorimetric detection and imaging of GSH. The fluorescence "Turn-On" sensing signal was generated by the electron or energy transfer process between GSH and NSB-MQDs, which exhibited a fluorescence quenching phenomenon with the increase of GSH. Meanwhile, the GSH-induced aggregation of NSB-MQDs generated a concentration-dependent hypochromic shift from yellow to pink. The analytical probe performed satisfactorily for GSH detection in the range of 50-325 μM with a low detection limit of 0.978 μM, and this sensing probe has been successfully applied to the detection of GSH in real samples. Furthermore, this dual-mode probe enables in situ imaging and monitoring of mitochondrial GSH with low cytotoxicity in living cells and zebrafish. The developed strategy not only provides insights into MXene-based nanoprobe engineering but also demonstrates a broad application prospect for the early diagnosis of diseases and biochemical imaging.