Manipulating surface structure of quantum dots based on dual response modes triggered by iron ions for visualization of hydrogen sulfide with a wide detection range

Abstract

Developing fluorescent turn-on probe to monitor hydrogen sulfide (H2S) in biosystem has attracted much attention due to its noninvasiveness, high spatial resolutions and superior signal to noise ratio. Considering the significant expression level of H2S in living organisms, it is a great challenge to further expand the response range to several hundred micromolar levels while keeping excellent sensitivity for such type of probes. Herein, we proposed a surface manipulation strategy on the highly emissive CuInS2 quantum dots (CIS QDs) by the recognition group with multiple response during assay to construct the H2S fluorescent turn-on probe. The studies demonstrated that the designed CIS/ZnS@Fe3+ nanoprobe can react with H2S by the modes of H2S-induced reduction of Fe3+ and subsequent metal-sulfide precipitation of Fe2+, whose produced fluorescent signal presented two-stage linear relationship with H2S amount. As a result, it not only possessed a considerable limit of detection of 0.68 μM and high selectivity, but also an extremely wide detection range of 0-300 μM, and was capable of H2S fluorescent imaging in living cells.