Black phosphorus quantum dots nanocomposites based activatable bimodal imaging and determination of intracellular glutathione

Abstract Glutathione (GSH) is closely related to many physiological processes, the sensitive determination of GSH is significant to the diagnostic and treatment of the specific diseases. In this work, an activatable bimodal imaging and determination strategy of GSH is proposed based on the nanocomposite of black phosphorus quantum dots (BPQDs) wrapped with manganese dioxide nanosheets (BPQDs@MnO2). The quenched fluorescence of BPQDs can be recovered with the addition of GSH, as a result of the reduction of MnO2. The BPQDs@MnO2 appears a linearly activatable fluorescence to the addition of GSH from 0.1 μM to 60 μM with a limit of detection of 35 nM (3σ/s). As the Mn2+ produced by the reduction of MnO2 is a good magnetic resonance imaging (MRI) contrast agent, the BPQDs@MnO2 is applied to the fluorescence/MRI bimodal imaging of intracellular GSH. MTT experiments prove the good biocompatibility of BPQDs@MnO2, and different kinds of cells are used to demonstrated that bimodal imaging intensity of cells incubated with BPQDs@MnO2 was dependent on the concentration of intracellular GSH. This strategy provided a new method for the activatable determination of GSH, and offered a promising platform for fluorescence/MRI bimodal imaging of GSH in living cells.