Development of selective, visible light-excitable, fluorescent magnesium ion probes with a novel fluorescence switching mechanism

Takuji Shoda, Kazuya Kikuchi, Hirotatsu Kojima, Yasuteru Urano, Hirokazu Komatsu, Koji Suzuki, Tetsuo Nagano

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46 Citations (Scopus)

Abstract

Novel fluorescent Mg2+ probes, 2′-carboxyfluorescein (2′-CF) and its derivatives, that are excitable by visible light, were designed, synthesized and characterized. After complexation with Mg2+, the absorption and emission maxima of these fluorescent probes were red-shifted and the fluorescence intensity was increased 11-fold at neutral pH. The apparent dissociation constant (Kd) of the Mg2+-2′-CF complex was 15.8 mM at neutral pH. The Kd of the Ca2+-2′-CF complex was about 10 times larger than that of the Mg2+ complex and the other derivatives showed similar characteristics. In contrast, all the commercially available fluorescent Mg2+ probes have a higher affinity for Ca2+ than Mg2+. 2′-CF fluoresced in alkaline solution (pH > 8) and the pKa value was 8.8. The pKa value of the Mg2+-2′-CF complex was 6.8, and the fluorescence intensity was increased in the neutral conditions. Thus, the addition of Mg2+ resulted in a lowering of the pKa and also an increase of the fluorescence intensity.

Original languageEnglish
Pages (from-to)719-723
Number of pages5
JournalAnalyst
Volume128
Issue number6
DOIs
Publication statusPublished - 2003 Jun 1

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

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    Shoda, T., Kikuchi, K., Kojima, H., Urano, Y., Komatsu, H., Suzuki, K., & Nagano, T. (2003). Development of selective, visible light-excitable, fluorescent magnesium ion probes with a novel fluorescence switching mechanism. Analyst, 128(6), 719-723. https://doi.org/10.1039/b212835g