Zn2+-triggered amide tautomerization produces a highly Zn 2+-selective, cell-permeable, and ratiometric fluorescent sensor

Zhaochao Xu, Kyung Hwa Baek, Ha Na Kim, Jingnan Cui, Xuhong Qian, David R. Spring, Injae Shin, Juyoung Yoon

Research output: Contribution to journalArticlepeer-review

672 Citations (Scopus)


It is still a significant challenge to develop a Zn2+-selective fluorescent sensor with the ability to exclude the interference of some heavy and transition metal (HTM) ions such as Fe2+, Co2+, Ni2+, Cu2+, Cd2+, and Hg2+. Herein, we report a novel amide-containing receptor for Zn2+, combined with a naphthalimide fluorophore, termed ZTRS. The fluorescence, absorption detection, NMR, and IR studies indicated that ZTRS bound Zn2+ in an imidic acid tautomeric form of the amide/di-2-picolylamine receptor in aqueous solution, while most other HTM ions were bound to the sensor in an amide tautomeric form. Due to this differential binding mode, ZTRS showed excellent selectivity for Zn2+ over most competitive HTM ions with an enhanced fluorescence (22-fold) as well as a red-shift in emission from 483 to 514 nm. Interestingly, the ZTRS/Cd2+ complex showed an enhanced (21-fold) blue-shift in emission from 483 to 446 nm. Therefore, ZTRS discriminated in vitro and in vivo Zn2+ and Cd2+ with green and blue fluorescence, respectively. Due to the stronger affinity, Zn2+ could be ratiometrically detected in vitro and in vivo with a large emission wavelength shift from 446 to 514 nm via a Cd2+ displacement approach. ZTRS was also successfully used to image intracellular Zn2+ ions in the presence of iron ions. Finally, we applied ZTRS to detect zinc ions during the development of living zebrafish embryos.

Original languageEnglish
Pages (from-to)601-610
Number of pages10
JournalJournal of the American Chemical Society
Issue number2
Publication statusPublished - 2010 Jan 20

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


Dive into the research topics of 'Zn2+-triggered amide tautomerization produces a highly Zn 2+-selective, cell-permeable, and ratiometric fluorescent sensor'. Together they form a unique fingerprint.

Cite this