Fluorescence sensing of glutathione based on the in-situ growth of carbon dots-manganese dioxide nanosheets

Blue fluorescent carbon dots with high purity were synthesized through a one-step hydrothermal method using citric acid and ethylenediamine as raw materials and then purification by column chromatography. In-situ controllable synthesis was used to prepare carbon dots-manganese dioxide (CDs-MnO2) nanosheets, with carbon dots as the seed, potassium permanganate as the manganese source and sodium citrate as the reducing agent. The as-prepared nanosheets were characterized by transmission electron microscopy, absorption spectroscopy, and fluorescence spectroscopy. It was found that MnO2 can be degraded by Glutathione (GSH) through a redox reaction, which restores the fluorescence of CDs. A new method for determining GSH was constructed using CDs-MnO2 fluorescence sensing. The method is simple and sensitive, with linear ranges of 0.1–5 μM and 10–60 μM, respectively, and a lowest detection limit of 0.034 μM. The method was successfully used for the determination of GSH in human serum, with satisfactory recoveries in the range of 98.9–100.1%.