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

Abstract

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 lysosome-targetable fluorescent probe (E)-2-(benzo[d]thiazol-2- yl)-4-methyl-6-((morpholinoimino)methyl)phenol (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.