A novel biosensor based on single-layer MoS2 nanosheets for detection of Ag(+).

In this work, we use for the first time single layer MoS2 as the fluorescence quencher to design a detection method for Ag(+) with excellent robustness, selectivity and sensitivity. To maintain the ultrathin MoS2, bulk MoS2 materials have been exfoliated by intercalation with lithium followed by reaction with water. As-prepared two-dimensional MoS2 not only has good water-solubility but also obtains high fluorescence quenching efficiency within 5 min. Importantly, the detection limit of this assay for Ag(+) (1 nM) was lower than the maximum limitation guided by the United States Environmental Protection Agency (EPA) and the World Health Organization (WHO). Further, this new Ag(+) probe was demonstrated in monitoring Ag(+) in lake water samples with satisfactory results.