Zn(2+) Binding-Enabled Excited State Intramolecular Proton Transfer: A Step toward New Near-Infrared Fluorescent Probes for Imaging Applications
- Authors
- Xu, Y., Liu, Q., Dou, B., Wright, B., Wang, J., and Pang, Y.
- ID
- ZDB-PUB-121206-6
- Date
- 2012
- Source
- Advanced Healthcare Materials 1(4): 485-492 (Journal)
- Registered Authors
- Liu, Qin
- Keywords
- none
- MeSH Terms
-
- Binding Sites
- Contrast Media/chemical synthesis
- Fluorescent Dyes/chemistry*
- HeLa Cells
- Humans
- Infrared Rays
- Microscopy, Fluorescence/methods*
- Nanoparticles*/ultrastructure
- Protons
- PubMed
- 23184782 Full text @ Adv. Healthc. Mater.
In order to facilitate the in vivo study of zinc-related biology, it is essential to develop a zinc-selective sensor that exhibits both near-infrared (NIR) emission and larger Stokes shift. A fluorescent sensor, Zinhbo-5, has been constructed by using bis(benzoxazole) ligand with 2, 2'-dipicolylamine (DPA) as metal ion receptor. In aqueous solution, Zinhbo-5 exhibits high sensitivity (K(d) = 2.58 nM(2) ) and selectivity for Zn(2+) cation, revealing about 14-fold fluorescence enhancement upon zinc binding to give green emission. Remarkably, Zn(2+) binding to Zinhbo-5 switches on the excited state intramolecular proton transfer (ESIPT), producing the desirable near-infrared region (over 710 nm) with large Stokes shift (ca. 240 nm). The new probe is demonstrated to be useful for in vivo imaging of the intracellular Zn(2+) ion. The Zinhbo-5 is also useful for detecting zinc ion distribution during the development of living zebrafish embryos.