Acetylcholinesterase (AChE) plays crucial roles in
numerous physiological processes such as cell differentiation, cell
apoptosis, and nerve tissue developments. Hence, it is highly
necessary to design a fluorescent probe for monitoring AChE
activity in complex living organisms. In this work, a near-infrared
(NIR) off-on probe (CyN) was developed for AChE detection.
CyN was exactly synthesized by introducing an N,N-dimethyl
carbamyl moiety to hemicyanine (CyOH). AChE can “light up”
strong NIR fluorescence through a cleavage special ester bond and transform CyN into CyOH. Moreover, CyN was qualified for
imaging the dynamic change of AChE activity in PC12 cells with retinoic acid or hypoxia stimulation. In particular, the probe has
been successfully applied for in situ tracing the intact distribution of AChE in living zebrafish. The observations indicate that major
occurrence sites of endogenic AChE on zebrafish are the yolk sac and neuromasts. Overall, CyN shows great potential for use in
AChE-related physiological studies.