Ratiometric fluorescence probe of Cu2+ and biothiols by using carbon dots and copper nanoclusters

A novel dual-emission ratiometric fluorescent probe based on N-doped yellow fluorescent carbon dots (y-CDs) and blue fluorescent copper nanoclusters (CuNCs) was established for quantitative determination of Cu2+ and biothiols. In this work, the Cu2+-(y-CDs) complexes formed by the chelation of y-CDs with Cu2+, showed an absorption peak at 430 nm that not only enhanced the fluorescence of y-CDs through inhibiting photoinduced electron transfer (PET) but also effectively quenched the fluorescence of CuNCs due to Forster resonance energy transfer (FRET). In addition, the chelation of y-CDs with Cu2+ could be inhibited by biothiols that prevented the fluorescence of y-CDs from being enhanced and the fluorescence of CuNCs from being quenched. On account of the changes of ratiometric signal, a dual-emission fluorescence probe for Cu2+ and biothiols determination was achieved. The proposed method exhibited high sensitivity for Cu2+ and biothiols in the ranges of 0.5-100 mu M and 0.8-50 mu M and the limits of detection (LODs) of Cu2+, glutathione (GSH), cysteine (Cys) and homocysteine (Hcy) were 0.21 mu M, 0.33 mu M, 0.39 mu M and 0.46 mu M, respectively. Subsequently, the established strategy presented an application prospect for the detection of Cu2+ and biothiols in real samples.