Dual Mechanism of an Intramolecular Charge Transfer (ICT)-FRET-Based Fluorescent Probe for the Selective Detection of Hydrogen Peroxide.

A dual-mechanism intramolecular charge transfer (ICT)-FRET fluorescent probe for the selective detection of H2 O2 in living cells has been designed and synthesized. This probe used a coumarin-naphthalimide hybrid as the FRET platform and a boronate moiety as the recognition group. Upon the addition of H2 O2 , the probe exhibited a redshifted (73 nm) fluorescence emission, and the ratio of fluorescence intensities at λ=558 and 485 nm (F558 /F485 ) shifted notably (up to 100-fold). Moreover, there was a good linearity (R2 =0.9911) between the ratio and concentration of H2 O2 in the range of 0 to 60 μm, with a limit of detection of 0.28 μm (signal to noise ratio (S/N)=3). This probe could also detect enzymatically generated H2 O2 . Importantly, it could be used to visualize endogenous H2 O2 produced by stimulation from epidermal growth factor.