Rapid and Label-Free Detection of Interferon Gamma via an Electrochemical Aptasensor Comprising a Ternary Surface Monolayer on a Gold Interdigitated Electrode Array

Shaowei Ding; Curtis Mosher; Xian Y Lee; Suprem R Das; Allison A Cargill; Xiaohui Tang; Bolin Chen; Eric S McLamore; Carmen Gomes; Jesse M Hostetter; Jonathan C Claussen

doi:10.1021/acssensors.6b00581

Rapid and Label-Free Detection of Interferon Gamma via an Electrochemical Aptasensor Comprising a Ternary Surface Monolayer on a Gold Interdigitated Electrode Array

ACS Sens. 2017 Feb 24;2(2):210-217. doi: 10.1021/acssensors.6b00581. Epub 2017 Jan 31.

Authors

Shaowei Ding, Curtis Mosher, Xian Y Lee, Suprem R Das¹, Allison A Cargill, Xiaohui Tang, Bolin Chen, Eric S McLamore², Carmen Gomes³, Jesse M Hostetter, Jonathan C Claussen¹

Affiliations

¹ Ames Laboratory , Ames, Iowa 50011, United States.
² Agriculture and Biological Engineering Department, Institute of Food and Agricultural Sciences, University of Florida , Gainesville, Florida 32611, United States.
³ Biological and Agricultural Engineering Department, Texas A&M University , College Station, Texas 77843, United States.

PMID: 28723140
DOI: 10.1021/acssensors.6b00581

Abstract

A label-free electrochemical impedance spectroscopy (EIS) aptasensor for rapid detection (<35 min) of interferon-gamma (IFN-γ) was fabricated by immobilizing a RNA aptamer capture probe (ACP), selective to IFN-γ, on a gold interdigitated electrode array (Au IDE). The ACP was modified with a thiol group at the 5' terminal end and subsequently co-immobilized with 1,6-hexanedithiol (HDT) and 6-mercapto-1-hexanolphosphate (MCH) to the gold surface through thiol-gold interactions. This ACP/HDT-MCH ternary surface monolayer facilitates efficient hybridization with IFN-γ and displays high resistance to nonspecific adsorption of nontarget proteins [i.e., fetal bovine serum (FBS) and bovine serum albumin (BSA)]. The Au IDE functionalized with ACP/HDT-MCH was able to measure IFN-γ in actual FBS solution with a linear sensing range from 22.22 pM to 0.11 nM (1-5 ng/mL) and a detection limit of 11.56 pM. The ability to rapidly sense IFN-γ within this sensing range makes the developed electrochemical platform conducive toward in-field disease detection of a variety of diseases including paratuberculosis (i.e., Johne's Disease). Furthermore, experimental results were numerically validated with an equivalent circuit model that elucidated the effects of the sensing process and the influence of the immobilized ternary monolayer on signal output. This is the first time that ternary surface monolayers have been used to selectively capture/detect IFN-γ on Au IDEs.

Keywords: aptamer capture probe; electrochemical impedance spectroscopy; equivalent circuit model; interdigitated electrode array; interferon gamma; ternary surface monolayer.