Non-Faradaic electrochemical impedance spectroscopy as a reliable and facile method: Determination of the potassium ion concentration using a guanine rich aptasensor

摘要

In this article we report the application of non-Faradaic mode of electrochemical impedance spectroscopy (EIS) for determination of potassium ion (K+) concentration using a guanine rich K+-selective aptasensor (K+-aptasensor). This is a simple, electroactive probe free, sensitive and reproducible method allowing determination of K+ ion concentration without any disturbance from electroactive probes used in similar works based on the Faradaic EIS method. Herein, a wide linear range of K+ ion concentrations (1 mu M-0.1 mM) with a 200 nM limit of detection was achieved which is better than most of the previously reported Faradaic biosensing methods. The proposed method maintains valuable applications when it is used for K+ determination in the presence of potentially important interferences in biological media. Thus, application of the non-Faradaic EIS method for sensing the concentration of K+ ion with the presented K+-aptasensor can find an important role in clinical assay. (C) 2015 Elsevier B.V. All rights reserved.