pH dependence of the fluorescence lifetime of FAD in solution and in cells

Md Serajul Islam, Masato Honma, Takakazu Nakabayashi, Masataka Kinjo, Nobuhiro Ohta

Research output: Contribution to journalArticlepeer-review

75 Citations (Scopus)


We have studied physiological parameters in a living cell using fluorescence lifetime imaging of endogenous chromophores. In this study, pH dependence of the fluorescence lifetime of flavin adenine dinucleotide (FAD), that is a significant cofactor exhibiting autofluorescence, has been investigated in buffer solution and in cells. The fluorescence lifetime of FAD remained unchanged with pH 5 to 9 in solution. However, the fluorescence lifetime in HeLa cells was found to decrease with increasing intracellular pH, suggesting that pH in a single cell can be estimated from the fluorescence lifetime imaging of FAD without adding exogenous fluorescent probes.

Original languageEnglish
Pages (from-to)1952-1963
Number of pages12
JournalInternational journal of molecular sciences
Issue number1
Publication statusPublished - 2013 Jan
Externally publishedYes


  • Autofluorescence
  • FAD
  • Fluorescence decay
  • Fluorescence lifetime imaging
  • Intracellular pH
  • Living cell

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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