A deep red ratiometric fluorescent probe for accurate detection of peroxynitrite in mitochondria

Peroxynitrite (ONOO⁻) is widespread within living organisms and has been implicated in many physiological and pathological processes. Since ONOO⁻ is mainly produced in mitochondria, accurate detection of ONOO⁻ in mitochondria can help us understand its specific mechanism of action in the organism. Rather than single-wavelength emissive mitochondrial probes, ratiometric fluorescent probes with longer emission wavelength, large emission shift, and specific mitochondrial targeting properties are more likely to obtain a more accurate ONOO⁻ content in mitochondria. To further avoid the interference by cytoplasmic ONOO⁻, we constructed a fluorescent probe MXMP with deep red emission and ratio properties, and it will be forbidden to enter the mitochondria after oxidation. In addition to its excellent selectivity and sensitivity, it shifted its fluorescence emission by up to 130 nm, with a detection limit of 84 nM.