Enhancing probe’s sensitivity for peroxynitrite through alkoxy modification of dicyanovinylchromene

An intramolecular charge transfer (ICT)–based fluorescent probe P-ONOO − was synthesized to detect ONOO − . After responding to peroxynitrite, the dicyano-vinyl group of P-ONOO − generates the aldehyde group, emitting strong green fluorescence accompanied by quenching of the yellow fluorescence. According to the calculated Fukui function, the modification of the alkoxy group can enhance the f + of P-ONOO − , which can enhance the probe’s nucleophilic addition reactivity with ONOO − . It has been experimentally verified that P-ONOO − shows fast response (within 30 s), excellent sensitivity (the detection limit = 10.4 nM), and good selectivity towards ONOO − . Additionally, the probe P-ONOO − has high membrane permeability and good biocompatibility, which can image endogenous ONOO − and exogenous ONOO − in HeLa cells. Graphical abstract