Nitrogen-doped MoS QDs as fluorescent probes for sensitive detection of curcumin and cell imaging.

Background: Curcumin has been used in traditional medicine because of its pharmacological activity, including antioxidant, antibacterial, anticancer, and anticarcinogenic properties. Therefore, sensitive and selective monitoring of curcumin is highly demand for practical application.

Results: In this study, we describe the construction of a fluorescence method for curcumin assay based on nitrogen-doped MoS quantum dots (N-MoS QDs). The N-MoS QDs are constructed by a solvothermal method using sodium molybdate and Cys as precursors. With the addition of curcumin, the bright blue fluorescence of N-MoS QDs is quenched by the inner filter effect (IFE). The QDs emitted bright blue fluorescence and could be quenched by the addition of curcumin via IFE. The dynamic range is the range of 0.1-10 μM for curcumin detection, with a detection limit of 59 nM. N-MoS QDs were applied for curcumin assay in real samples with good recovery. In addition, the N-MoS QDs exhibited relative low cytotoxicity and could be applied for fluorescence-based imaging in biological samples.

Significance: Our study indicates that the sensor possesses good selectivity to monitor curcumin in water samples, human urine samples, ginger powder samples, mustard samples, and curry samples with satisfactory recoveries. The N-MoS QDs possess less cytotoxicity with excellent biocompatibility and were applied for in vitro cell imaging.