Label-Free, Electrochemical Quantitation of Potassium Ions from Femtomolar Levels

Bicheng Zhu, Marsilea A. Booth, Han Young Woo, Justin M. Hodgkiss, Jadranka Travas-Sejdic

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

In this communication, a label-free and sensitive electrochemical method to detect potassium ions is proposed. The conducting polymer polypyrrole was used as both an anchor for the probe and a transducer of the detection event. A K+-specific G-rich aptamer was applied as a recognition element, which folded into the G-quadruplex structure in the presence of K+, and this resulted in an increase in the electrode impedance. The combination of the K+-selective aptamer and the porous conducting polymer as a signal transducer afforded a successful sensor platform. The sensor responded approximately logarithmically over a wide dynamic range of K+ concentrations from 20 fm to 1mm, with a very low detection limit of 14.7fm and excellent discrimination against other ions. Additionally, electrochemical impedance spectroscopy was used to study the kinetics of K+ binding at the conducting polymer-immobilized aptamer surface, which indicated strong binding between the two. This work demonstrates a powerful approach for the sensitive, selective, and direct electrochemical detection of metal ions based on the switching conformation of G-rich aptamers attached to a porous conducting polymer surface. This assay scheme can be expanded to the detection of a wide range of targets by modifying the aptamer structure as a recognizing moiety.

Original languageEnglish
Pages (from-to)2169-2175
Number of pages7
JournalChemistry - An Asian Journal
Volume10
Issue number10
DOIs
Publication statusPublished - 2015 Oct 1
Externally publishedYes

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Conducting polymers
Labels
Potassium
Ions
Transducers
Sensors
Anchors
Electrochemical impedance spectroscopy
Metal ions
Conformations
Assays
Electrodes
Kinetics
Communication

Keywords

  • aptasensors
  • electrochemistry
  • kinetics
  • polymers
  • potassium

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Label-Free, Electrochemical Quantitation of Potassium Ions from Femtomolar Levels. / Zhu, Bicheng; Booth, Marsilea A.; Woo, Han Young; Hodgkiss, Justin M.; Travas-Sejdic, Jadranka.

In: Chemistry - An Asian Journal, Vol. 10, No. 10, 01.10.2015, p. 2169-2175.

Research output: Contribution to journalArticle

Zhu, Bicheng ; Booth, Marsilea A. ; Woo, Han Young ; Hodgkiss, Justin M. ; Travas-Sejdic, Jadranka. / Label-Free, Electrochemical Quantitation of Potassium Ions from Femtomolar Levels. In: Chemistry - An Asian Journal. 2015 ; Vol. 10, No. 10. pp. 2169-2175.
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