Carbon quantum dot-gold nanocluster nanosatellite for ratiometric fluorescence probe and imaging for hydrogen peroxide in living cells

[Display omitted] •Carbon quantum dot-gold nanocluster nanosatellite was synthesized.•High FRET efficiency between carbon quantum dots and gold nanoclusters was displayed.•A sensitive ratiometric fluorescence probe for H2O2 was proposed.•The response toward H2O2 of proposed nanosatellite probe was selective.•The capability of the nanosatellite probe was validated by intracellular H2O2 imaging. Developing probes for sensitive H2O2 detection is critical for understanding its related physiological and pathological processes. In this study, novel carbon quantum dot-gold nanocluster (CQD-AuNC) nanosatellite with high fluorescence energy transfer efficiency (∼40%) and dual-emission fluorescent properties have been exploited for fluorescence ratiometric sensing of H2O2. The sensing mechanism was based on the fact that H2O2 can quench the red emission of AuNCs. Under the optimal conditions, the CQD-AuNC nanosatellite probe was sensitive to H2O2 in the range from 5.0nM to 80nM with a limit of detection of 2.9nM. The practicality of the proposed CQD-AuNC nanosatellite probe was validated by imaging H2O2 in living cells.