Cationic conjugated polyelectrolytes-triggered conformational change of molecular beacon aptamer for highly sensitive and selective potassium ion detection

Boram Kim, In Hwan Jung, Mijeong Kang, Hong Ku Shim, Han Young Woo

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133 Citations (Scopus)


We demonstrate highly sensitive and selective potassium ion detection against excess sodium ions in water, by modulating the interaction between the G-quadruplex-forming molecular beacon aptamer (MBA) and cationic conjugated polyelectrolyte (CPE). The K +-specific aptamer sequence in MBA is used as the molecular recognition element, and the high binding specificity of MBA for potassium ions offers selectivity against a range of metal ions. The hairpin-type MBA labeled with a fluorophore and quencher at both termini undergoes a conformational change (by complexation with CPEs) to either an open-chain form or a G-quadruplex in the absence or presence of K + ions. Conformational changes of MBA as well as fluorescence (of the fluorophore in MBA) quenching or amplification via fluorescence resonance energy transfer from CPEs provide clear signal turn-off and -on in the presence or absence of K +. The detection limit of the K + assays is determined to be ∼1.5 nM in the presence of 100 mM Na + ions, which is ∼3 orders of magnitude lower than those reported previously. The successful detection of 5′-adenosine triphosphate (ATP) with the MBA containing an ATP-specific aptamer sequence is also demonstrated using the same sensor scheme. The scheme reported herein is applicable to the detection of other kinds of G-rich aptamer-binding chemicals and biomolecules.

Original languageEnglish
Pages (from-to)3133-3138
Number of pages6
JournalJournal of the American Chemical Society
Issue number6
Publication statusPublished - 2012 Feb 15
Externally publishedYes


ASJC Scopus subject areas

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

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