MoS quantum dots as a unique fluorescent "turn-off-on" probe for the simple and rapid determination of adenosine triphosphate.

We report a one-step hydrothermal method for the preparation of fluorescent molybdenum disulfide quantum dots (MoS QDs) and demonstrate the feasibility of fluorescent "turn-off-on" sensing of adenosine triphosphate (ATP) by using the MoS QDs. MoS QDs having strong blue-green fluorescence at 506 nm and good water-solubility were successfully synthesized by using ammonium tetrathiomolybdate as a single precursor. The fluorescence of MoS QDs was first quenched by Fe through the formation of a MoS QDs/Fe complex. ATP with the ability to coordinate with Fe caused the dissociation of MoS QDs/Fe, resulting in the final release of MoS QDs and the recovery of fluorescence through a one-step competitive chelating process that took only 10 min to reach equilibrium at room temperature (RT). Facile and rapid sensing of Fe and ATP could thus be achieved through the fluorescent "turn-off-on" strategy. Good linear relationships were obtained over the concentration ranges of 0-200 μM for Fe and 0-140 μM for ATP with a lowest detectable concentration of 5 μM for ATP. Satisfactory results were obtained when the method was applied to a standard addition recovery trial of ATP in human serum samples. No complex surface modification during the preparation or detection process was needed based on the fluorescent "turn-off-on" method of the MoS QDs, which suggests its great potential in fluorescent sensing.