Rational design of an iminocoumarin-based fluorescence probe for peroxynitrite with high signal-to-noise ratio

As a high reactive oxygen species (ROS) and a reactive nitrogen species (RNS), peroxynitrite anion (ONOO-) is widely present in organisms and plays influential roles in physiological and pathological processes. It is of great significance to develop effective fluorescent probes for imaging peroxynitrite variation in living systems. Herein we present a novel fluorescent probe TQC0 for monitoring ONOO- based on the iminocoumarin platform, and this probe was synthesized by the knoevenagel condensation between a dihydropyridine-salicylaldehyde derivative and 2-benzothiazole-acetonitrile, and subsequently masked with the boronate moiety. The obtained probe TQC0 exhibited a high signal-to-noise ratio (206-fold) and a quick 'turn-on' response (about 10 min) with great selectivity and sensitivity. Furthermore, the probe TQC0 was successfully applied for imaging ONOO- in living cells with low cytotoxicity. A novel fluorescent probe TQC0 was rationally designed and synthesized for monitoring peroxynitrite anion (ONOO-) based on the iminocoumarin scaffold. This probe exhibited 206-fold enhancement and a quick 'turn-on' response (about 10 min) toward ONOO- with great selectivity and high sensitivity, which enabled the probe TQC0 to visualize ONOO- in living cells. image