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

Developing probes for sensitive H 2 O 2 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 H 2 O 2 . The sensing mechanism was based on the fact that H 2 O 2 can quench the red emission of AuNCs. Under the optimal conditions, the CQD-AuNC nanosatellite probe was sensitive to H 2 O 2 in the range from 5.0 nM to 80 nM with a limit of detection of 2.9 nM. The practicality of the proposed CQD-AuNC nanosatellite probe was validated by imaging H 2 O 2 in living cells. [ABSTRACT FROM AUTHOR]