A morpholino hydrazone-based lysosome-targeting fluorescent probe with fast response and high sensitivity for imaging peroxynitrite in living cells

Peroxynitrite (ONOO-) plays important roles in many pathophysiological processes and its subcellular detection draws increasing attention. In this study, we designed and prepared a novel lysosometargetable fluorescent probe (E)-2-(benzo[d]thiazol-2-yl)-4-methyl-6-((morpholinoimino)methyl)phe nol (BMP) for selective detection of ONOO- in living systems by incorporating a reactive morpholino hydrazone as new ONOO- response site into a benzothiazole derivative as fluorophore. After reaction with ONOO-, an obvious fluorescence increase (83-fold) was observed accompanied with distinct dual colorimetric and fluorescence changes. Probe BMP displayed the merits of fast response (<3 s), ultrasensitivity (LOD = 6 nM) and high selectivity towards ONOO- over other physiological species including ROS/RNS. Most importantly, the probe was capable of imaging ONOO- in lysosomes of living cells with good cell permeation and negligible cytotoxicity. Therefore, this research provides an effective tool to study the functions of ONOO- in lysosomes. (C) 2021 Elsevier B.V. All rights reserved.