Detection of endogenous hydrogen peroxide in living cells with para-nitrophenyl oxoacetyl rhodamine as turn-on mitochondria-targeted fluorescent probe

Hydrogen peroxide (H2O2) is a small molecule of reactive oxygen species, mainly produced by cell mitochondria, which plays an important role in physiological processes. Excess of H2O2 in normal cells could causes a variety of diseases. For that reason, it is very significant to emerge a detection method with high-precision for H2O2. Herein, we reported a structurally novel fluorescent probe, para-nitrophenyl oxoacetyl rhodamine (RhB-NIR) for the detection of H2O2 levels in living cells. The results show that the Stokes shift for RhB-NIR is 140 nm, much larger than those for other reported rodamine derivatives. RhB-NIR shows satisfactory specificity and high sensitivity for the detection of H2O2. Excellent linear relationship with H2O2 within a certain concentration range (0–10 μM) was displayed, and the limit of detection (LOD) is 61 nM. More importantly, RhB-NIR realized fluorescence imaging of H2O2 in living cells. In addition, RhB-NIR also shows great potential for targeting mitochondria in cell colocalization experiments, in which the Pearson's coefficient is 0.91 using Rhodamine 123 as a reference. This probe will be a promising tool for detecting H2O2 in the future research.