A Fluorescent Switch Sensor for Glutathione Detection Based on Mn-doped CdTe Quantum Dots - Methyl Viologen Nanohybrids

In the work, a fluorescence switch sensor consists of Mn-doped CdTe quantum dots (QDs) - methyl viologen (MV2+) nanohybrid is fabricated. In the sensor, MV2+ plays a role in turning the QDs fluorescence to the “OFF” state due to the efficient electron transfer process while glutathione (GSH) could turn “ON” the native QDs fluorescence by effectively releasing QDs from the QDs-MV2+ nanohybrids. In addition, the recovery level of QDs fluorescence is closely related to the amount of GSH. Based on this phenomenon, a reliable and convenient GSH quantitative determination method is established, which not only has a wide determination range of 1.2–200 μM, a low detection limit of 0.06 μM and a short detection time but also can realize the selective detection of GSH upon other competitive biothiols (homocysteine and cysteine) that are coexistent in biological systems. The developed sensor will greatly benefit to the study of GSH amount, helping the understanding of its function in biological systems.