Signal-Switchable Electrochemiluminescence System Coupled with Target Recycling Amplification Strategy for Sensitive Mercury Ion and Mucin 1 Assay

Abstract

In the present work, we first found that mercury ion (Hg(2+)) has an efficient quenching effect on the electrochemiluminescence (ECL) of N-(aminobutyl)-N-(ethylisoluminol) (ABEI). Since we were inspired by this discovery, an aptamer-based ECL sensor was fabricated based on a Hg(2+) triggered signal switch coupled with an exonuclease I (Exo I)-stimulated target recycling amplification strategy for ultrasensitive determination of Hg(2+) and mucin 1 (MUC1). Concretely, the ECL intensity of ABEI-functionalized silver nanoparticles decorated graphene oxide nanocomposite (GO-AgNPs-ABEI) was initially enhanced by ferrocene labeled ssDNA (Fc-S1) (first signal switch "on" state) in the existence of H2O2. With the aid of aptamer, assistant ssDNA (S2) and full thymine (T) bases ssDNA (S3) modified Au nanoparticles (AuNPs-S2-S3) were immobilized on the sensing surface through the hybridization reaction. Then, via the strong and stable T-Hg(2+)-T interaction, an abundance of Hg(2+) was successfully captured on the AuNPs-S2-S3 and effectively inhibited the ECL reaction of ABEI (signal switch "off" state). Finally, the signal switch "on" state was executed by utilizing MUC1 as an aptamer-specific target to bind aptamer, leading to the large decrease of the captured Hg(2+). To further improve the sensitivity of the aptasensor, Exo I was implemented to digest the binded aptamer, which resulted in the release of MUC1 for achieving target recycling with strong detectable ECL signal even in a low level of MUC1. By integrating the quenching effect of Hg(2+) to reduce the background signal and target recycling for signal amplification, this proposed ECL aptasensor was successfully used to detect Hg(2+) and MUC1 sensitively with a wide linear response.

Poly(adenine)-mediated DNA-functionalized gold nanoparticles for sensitive detection of mercury ions in aqueous media

“…[19][20][21] The thymine (T) base of oligonucleotide specic binding with Hg 2+ to form "T-Hg 2+ -T" complex, and since it was reported, 22 many sensors for detection of Hg 2+ have been developed based on it. 23,24 Liu developed a Hg 2+ detection method with a detection limit of 0.5 nM by using Hg 2+ specic probe (18T) and the intercalation dye SYBR Green I. 25 In order to expand the application of detection methods, nanomaterials have been employed to construct sensitive sensors for Hg 2+ .…”

Electrochemiluminescent functional nucleic acids‐based sensors for food analysis

“…Zhou et al introduced the amplification of RCA to report a highly sensitive ECL sensor for Hg 2+ . Besides the polymerase, Jiang et al also used exonuclease I to develop ECL sensor for Hg 2+ . Embedded ECL reagents owning high affinity with dsDNA, Ru(phen) 3 2+ and Ru‐dppz, have been also employed to develop label‐free ECL sensors for Hg 2+ .…”

A Novel Surface‐Tethered Double‐Signal Electrochemiluminescence Sensor Based on Luminol@Au and CdS Quantum Dots for Mercury Ion Detection

“…Therefore, reliable methods for detection of Hg 2+ have become increasingly important. In recent years, ECL has been widely used as one of the main method of detecting Hg 2+ owing to its excellent performance in terms of sensitivity, stability and so on ,. In addition, a large number of studies have shown that the design of the specific binding of T to Hg 2+ is the basis for ensuring good selectivity of the sensor ,.…”