A novel pyridinium-based fluorescent probe for ratiometric detection of peroxynitrite in mitochondria

Peroxynitrite (ONOO^-) is a primary kind of reactive oxygen species. Excessive ONOO^- can induce oxidative damage to biomolecules and further results in various diseases. So, quantitative monitoring ONOO^- with excellent selectivity and sensitivity is imperative for elucidating its role in biological processes. In this study, a novel pyridinium fluorescent ONOO^- probe (CPC) has been constructed base on ICT-modulated by combining coumarin fluorophore and diphenylphosphinate recognition group. The fluorescence response of CPC for ONOO^- is realized via the removal of diphenylphosphinate group. The probe CPC shows prominent features for detection of ONOO^- including fast response rate (within 3 min), excellent selectivity and sensitivity, distinct colorimetric (red to green), and a large emission wavelength shift (105 nm). The emission intensity ration (I₅₃₈/I₆₄₃) exhibits 153-fold enhancement along with the increasing ONOO^- and the detection limit is as low as 1.60 × 10^-8 M. These good response properties make CPC possible to quantitative detection of ONOO^- concentration. By using the strategy, the ratiometric CPC has been employed to detection of mitochondrial ONOO^- in live cell successfully.