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

Chemistry - An Asian Journal - Tập 10 Số 10 - Trang 2169-2175 - 2015
Bicheng Zhu1, Marsilea A. Booth2, Han Young Woo3, Justin M. Hodgkiss4,5, Jadranka Travaš-Sejdić1,5
1School of Chemical Sciences, Polymer Electronics Research Centre (PERC), The University of Auckland, 23 Symonds Street, Auckland, New Zealand
2Digital Sensing Limited, 16 Beatrice Tinsley Cresent, Albany, Auckland, 0632 New Zealand
3Department of Cogno Mechatronics Engineering, Pusan National University, Miryang, 627-706 Republic of Korea
4School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
5The MacDiarmid Institute for Advanced Materials and Nanotechnology, Laby 410, Gate 6 Kelburn Parade, Kelburn, Wellington, New Zealand

Tóm tắt

AbstractIn 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 1 mm, with a very low detection limit of 14.7 fm 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.

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Chemistry - An Asian Journal

Tập 10 Số 10

2169-2175

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