A turn-on fluorescent probe based on π-extended coumarin for imaging endogenous hydrogen peroxide in RAW 264.7 cells

Hydrogen peroxide (H2O2), one of reactive oxygen species, is implicated in the biological process of oxidative metabolism and signal transduction. However, the detection of H2O2 in vivo is restricted by background interference in the context of fluorescence probes. In this work, by regulating the intramolecular charge transfer (ICT) process, a novel ?turn-on? fluorescent probe BC-OB is constructed based on a ?-extended coumarin and a pdihydroxyborylbenzyloxycarbonyl moiety as an optimized hydrogen peroxide reactive site. The mechanism was identified by HPLC and HRMS: after the H2O2-mediated oxidation of aryl boronate moiety on BC-OB, the hydrolysis resulted in a release of the ?-extended coumarin with specific fluorescence response. The sensitive response of probe BC-OB to H2O2 was revealed by high fluorescence quantum yields (? up to 0.68) and low detection limit (0.47 ?M) due to the enhancement of the ICT process. Further, probe BC-OB could successfully trap endogenous H2O2 in RAW 264.7 cells, promising it would be used as an efficient indicator for imaging H2O2.