Construction of a dual-excitation ratiometric fluorescent probe for determining peroxynitrite levels in living cells and zebrafish.

[Display omitted] • A novel dual-excitation ratiometric fluorescent probe for the specific detection of ONOO– was designed and synthesized. • Probe 1 showed fast response toward ONOO– with high selectivity and sensitivity. • Probe 1 can specifically image endogenous and exogenous ONOO– in living cells and zebrafish. Peroxynitrite (ONOO−) is a highly reactive oxygen species that plays a critical role in many physiological and pathological processes of cell function. This study aimed to propose a ratiometric fluorescent probe BDHCA derived from coumarin for determining the ONOO− level. ONOO− could specifically induce oxidative cleavage of the conjugated C = C double bond in probe BDHCA , providing a fluorescent ratiometric output. The response of probe BDHCA to ONOO− was selective, fast, and highly sensitive, with a detection limit of 50.3 nM. Biological imaging experiments suggested that probe BDHCA could be used to image ONOO− in living RAW264.7 cells and zebrafish. [ABSTRACT FROM AUTHOR]