A salicylaldehyde benzoyl hydrazone based near-infrared probe for copper(ii) and its bioimaging applications

Developing highly sensitive and selective methods for Cu(2+) detection in living systems is of great significance in clinical copper-related disease diagnosis. In this work, a near infrared (NIR) fluorescent probe, CySBH, with a salicylaldehyde benzoyl hydrazone group as a selective and sensitive receptor for Cu(2+) was designed and synthesized. The specific coordination of the salicylaldehyde benzoyl hydrazone group in CySBH with Cu(2+) can induce a distinct quench of the fluorescence intensity, allowing for real-time tracking of Cu(2+). We have demonstrated that CySBH could rapidly recognize Cu(2+) with good selectivity and high sensitivity. Moreover, on the basis of low cell cytotoxicity, the probe was used to visualize Cu(2+) in two cell lines by fluorescence imaging. Furthermore, CySBH can also be used to monitor Cu(2+)in vivo due to its NIR emission properties. These overall results illustrate that the NIR fluorescent probe CySBH provides a novel approach for the selective and sensitive monitoring of Cu(2+) in living systems.