A sensitive polymer dots-manganese dioxide fluorescent nanosensor for “turn-on” detection of glutathione in human serum

Abstract

Abstract Glutathione (GSH), as a crucial endogenous thiol and antioxidant, plays an essential role in the biological system, and its abnormal levels are closely related to various diseases. Therefore, it continues to be of enormous significance to develop a sensitive and efficient method for the assay of GSH. Herein, we report a facile and sensitive polymer dots (PDs)-manganese dioxide (MnO2) nanosensor for turn-on assay of GSH. In this sensing system, the PDs with strongly green fluorescence were prepared by a mild one-step method using hydroquinone and ethylenediamine as precursors, and the fluorescence of PDs can be quenched by MnO2 nanosheets. The PDs-MnO2 nanosensor was the turn-off state. In the presence of GSH, however, the fluorescence of the PDs-MnO2 nanosensor can remarkably recover because MnO2 nanosheets can be reduced into Mn2+ by GSH. The PDs-MnO2 nanosensor was the turn-on state. Based on the change of the fluorescence signal from turn-off switched to turn-on, a sensitive method was successfully constructed to detect GSH. We also systematically discussed the mechanism of the PDs-MnO2 nanosensor for GSH assay, indicating that the MnO2 nanosheets-induced the fluorescence quenching was derived from inner filter effect (IFE). The PDs-MnO2 nanosensor toward GSH showed a wide linear range from 0.5 to 200 μM and high sensitivity with a limit of detection of 0.10 μM. The as-developed PDs-MnO2 nanosensor was also successfully applied to detect GSH in human serum with satisfactory results.