Internal standard-based SERS aptasensor for ultrasensitive quantitative detection of Ag+ ion

Yan Wu; Tingting Jiang; Zhaoyang Wu; Ruqin Yu

doi:10.1016/j.talanta.2018.03.014

Internal standard-based SERS aptasensor for ultrasensitive quantitative detection of Ag⁺ ion

Talanta. 2018 Aug 1:185:30-36. doi: 10.1016/j.talanta.2018.03.014. Epub 2018 Mar 9.

Authors

Yan Wu¹, Tingting Jiang², Zhaoyang Wu³, Ruqin Yu²

Affiliations

¹ State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China; Department of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Inorganic Special Functional Materials, Yangtze Normal University, Chongqing, Fuling 408003, People's Republic of China.
² State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
³ State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China. Electronic address: zywu@hnu.edu.cn.

PMID: 29759204
DOI: 10.1016/j.talanta.2018.03.014

Abstract

A ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods was proposed for the ultrasensitive and reproducible quantitative detection of silver ion (Ag⁺) with Au@Ag core-shell nanoparticle (Au@Ag NP) substrate. In principle, the thiolated 5'-Rox C-containing labeled aptamer probe (Rox-aptamer) is firstly immobilized on the SERS substrate surface and then hybridizes with the complementary DNA (cDNA) to form a rigid double-stranded DNA (dsDNA), in which the Rox Raman labels is used to produce the Raman signal. Furthermore, the pyridine is employed as an IS element to provide the ratiometric determination of target. In the presence of Ag⁺, the Rox-aptamer is turned into the cytosine (C)-Ag⁺-C mediated hairpin structure, which remarkably reduces the distance between the Rox labels and the Au@Ag NP surface responsible for a measurable 'turn-on' signal change of Rox. This IS-based ratiometric SERS aptasensor exhibits a limit of detection of 50 pM for Ag⁺ with a linear detection range from 0.1 to 100 nM and the shortcoming of irreproducibility of SERS signal could be overcome. The proposed method provides a simple, robust, and rapid approach for the sensitive and reproducible quantitative detection of Ag⁺, and it could also be used for the detection of other metal ions which exhibits specific interactions with natural or synthetic bases.

Keywords: Cytosine-Ag(+)- cytosine; Internal standard; Sensor; Silver ion; Surface-enhanced Raman scattering.