Pteridine-based fluorescent pH sensors designed for physiological applications

Na'Il Saleh, John Graham, Akef Afaneh, Yaseen A. Al-Soud, Georg Schreckenbach, Fatima T. Esmadi

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


New derivatives of pteridine, namely 6,7-diphenyl-2-morpholinylpterin (DMPT) and 6-thienyllumazine (TLM) were designed and easily synthesized in a rational way for pH-fluorescence sensing near physiological pH. The dual-excitation ratiometric sensing was based on the distinct spectral properties of the fluorophore in its neutral and deprotonated states. Density Functional Theory (DFT) calculations were used to determine structures, gas phase acidities and pK a values for the new dyes. Substitutions on pterin (PT) and lumazine (LM) structures with phenyl, thienyl or morpholinyl groups enhanced the acidity of the new dyes. DMPT displays visible turn-on emission signals from blue to cyan (bluish-green) upon changing the pH from acidic to basic around pK a of 7.2. The advantages of the new pteridine dyes over those previously known pH sensors are discussed in details in terms of their facile preparation and functionalization, pK a tuning strategy, wide responsive and resolved signal around physiological pH, photostability, water solubility, and adequacy for intracellular pH measurements.

Original languageEnglish
Pages (from-to)63-73
Number of pages11
JournalJournal of Photochemistry and Photobiology A: Chemistry
Publication statusPublished - Nov 1 2012


  • DFT calculations
  • Fluorescent pH sensors
  • Physiological pH
  • Protonation/deprotonation
  • Pteridine

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Physics and Astronomy


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