Ratiometric emission fluorescent pH probe for imaging of living cells in extreme acidity

Weifen Niu, Li Fan, Ming Nan, Zengbo Li, Dongtao Lu, Man Shing Wong, Shaomin Shuang, Chuan Dong*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

110 Citations (Scopus)


A novel ratiometric emission fluorescent probe, 1,1-dimethyl-2-[2-(quinolin-4-yl)vinyl]-1H-benzo[e]indole (QVBI), is facilely synthesized via ethylene bridging of benzoindole and quinoline. The probe exhibits ratiometric fluorescence emission (F522nm/F630nm) characteristics with pKa 3.27 and linear response to extreme-acidity range of 3.8-2.0. Also, its high fluorescence quantum yield (φ = 0.89) and large Stokes shift (110 nm) are favorable. Moreover, QVBI possesses highly selective response to H+ over metal ions and some bioactive molecules, good photostability, and excellent reversibility. The probe has excellent cell membrane permeability and is further applied successfully to monitor pH fluctuations in live cells and imaging extreme acidity in Escherichia coli cells without influence of autofluorescence and native cellular species in biological systems.

Original languageEnglish
Pages (from-to)2788-2793
Number of pages6
JournalAnalytical Chemistry
Issue number5
Publication statusPublished - 3 Mar 2015

Scopus Subject Areas

  • Analytical Chemistry


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