Intramolecular hydrogen bond driven specific nucleophilic addition for highly selective detection of NE and its tumor imaging

Abstract

Pheochromocytoma is an enormous threat to people's health due to its complications. However, it is only known to secrete peripheral catecholamine neurotransmitters (including norepinephrine), but the changes of catecholamine in tumor tissues are unclear. Detection of individual catecholamine neurotransmitters has been a major challenge. However, NE has a unique amino ethanol structure. Here we present a particular mechanism, which was an interesting discovery. In this study, we found that NE can react with pyranium salt in a rapid specific addition reaction. Furthermore, coumarin conjugation can construct a ratiometric fluorescence response. Compared with previous benzothiodiazole sites, the selectivity and reaction rate have been improved, especially the reaction rate has been significantly accelerated. In view of the excellent reactivity, the probe was further used for norepinephrine in pheochromocytoma cell and tumor tissue. Conceptually, we propose a new site to detect norepinephrine, which provides a new idea for the design of norepinephrine fluorescent probe and will enhance the understanding of the physiological and pathological mechanism of norepinephrine.