A water-soluble fluorescent chemosensor having a high affinity and sensitivity for Zn2+ and its biological application

• Published in: Sensors and actuators. B, Chemical Vol. 259; pp. 484 - 491
• Main Authors: Li, Qing-Feng, Wang, Jin-Tao, Wu, Shuyi, Ge, Gen-Wu, Huang, Jingbin, Wang, Zhenling, Yang, Piaoping, Lin, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.04.2018
• Subjects: 8-aminoquinoline; Carboxyl groups; Fluorescence imaging; Water soluble; Zinc ions; Carboxyl groups; Water soluble; Fluorescence imaging; Zinc ions; 8-aminoquinoline
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.12.099

A water-soluble, selective fluorescent chemosensor with high affinity for Zn2+ was developed for bio-imaging application. [Display omitted] •A water soluble fluorescent chemosenor with high affinity and sensitivity for Zn2+ was developed.•The designed two carboxyl groups which played the role of solubilization was involved in the coordination of Zn2+.•The chemosenor can selectively detect Zn2+via a chelation induced enhanced fluorescence effect.•The chemosenor was successfully applied for bio-imaging of Zn2+ in HeLa cell. A water soluble 8-aminoquinoline based fluorescent Zn2+ chemosensor (AQZ-2COOH) containing two carboxylic groups has been synthesized. The designed two carboxyl groups not only greatly improved the water solubility of this chemosensor but also increased its affinity for Zn2+. It has been proved that AQZ-2COOH, a pentadentate N, O-chelating ligand was able to coordinate with Zn2+ through three nitrogen atoms and two oxygen atoms, resulting in the formation of a stable Zn2+ complex, and the binding constant between AQZ-2COOH and Zn2+ was determined to be 3.6 × 109 M−1. Furthermore, AQZ-2COOH shows 39-fold fluorescence enhancement upon binding of Zn2+ in aqueous solution. However, this remarkable emission enhancement did not occur when other metal ions were present. Further study revealed that AQZ-2COOH had low biotoxicity, and live cell imaging showed that AQZ-2COOH can be efficiently phagocytized by HeLa cells, a visible green fluorescence from the intracellular area was observed after incubation with AQZ-2COOH and Zn2+ for 3 h, suggesting that AQZ-2COOH can be a promising candidate for detection of mobile Zn2+ in biological systems.