A highly selective fluorescent probe for monitoring exogenous and endogenous ONOO⁻ fluctuations in HeLa cells

As a typical reactive oxygen species, peroxynitrite (ONOO⁻) plays vital roles in various biological functions and pharmacological activities. Specific, sensitive and rapid fluorescent probes are helpful tools for monitoring endogenous peroxynitrite. In this work, a highly selective fluorescent probe BTCBE was designed based on benzothiazole-2-acetonitrile and 4-formylphenylboronic acid pinacol cyclic ester. BTCBE showed the merits of rapid response (<1 min) and prominent sensitivity (LOD = 4.7 nM). It showed an excellent selectivity towards ONOO⁻ over NaClO and H₂O₂. Moreover, BTCBE was successfully used for bioimaging exogenous and endogenous ONOO⁻ in HeLa cells.