Sensitive Detection of Hg²⁺ with Switchable Electrochemiluminescence Luminophore and Disposable Bipolar Electrode

Abstract

A novel paper-based bipolar electrode-electrochemiluminescence (pBPE-ECL) switch system was used for the rapid, labelfree, and sensitive detection of Hg 2 + . In the proposed approach, Hg 2 + selectively mediates two thymine-enriched singlestranded DNA probes to form double-stranded DNA (dsDNA). In the presence of Hg 2 + , the "light-switch" molecule [Ru(phen) 2 dppz] 2 + can freely intercalate into the base pairs of the dsDNA, resulting in intense ECL emission. The assay takes advantage of the wireless pBPE-ECL platform to yield a low-cost, disposable, and sensitive analysis. The system has a limit of 0.1 nM for Hg 2 + detection. We also showed that the system can be used to distinguish Hg 2 + over other metal ions, including Pb

Electrochemiluminescence Detection in Paper‐Based and Other Inexpensive Microfluidic Devices

“…The same group also recently reported the use of a similar device for the detection of Hg 2 + in drinking and lake water. [40] In this device, the bipolar and driving electrodes were screen printed with conductive carbon paste. This was the first report of using BPE-ECL for the detection of Hg 2 + .…”

“…This was the first report using [Ru(phen) 2 dppz] 2+ at a BPE on a paper‐microfluidic device. The same group also recently reported the use of a similar device for the detection of Hg 2+ in drinking and lake water . In this device, the bipolar and driving electrodes were screen printed with conductive carbon paste.…”

Electrochemiluminescence Systems for Metal‐Ion Detection: A Systematic Review

“…[64] Furthermore, a paper-based bipolar electrode (pBPE) was demonstrated for the rapid, label-free, and sensitive detection of Hg(II), wherein the paper used in the assay could act as a filter as it was compatible with samples containing solid particles. [71] Moreover, a 3D functionalized paper-based ECL device was developed to detect Pb(II) and Hg(II) simultaneously by applying two ECL nanoprobes, carbon nanocrystals (CNCs) capped silica nanoparticles (Si@CNCs) and Ru(bpy) 3 2 + -gold nanoparticles (AuNPs) aggregates (Ru@AuNPs). [93] Benefiting the DNAzyme-based strategy, the ultrasensitive detection of each metal can be determined in the simple platform even though different metal ions coexist in one paper working zone.…”

Bipolar (Bio)electroanalysis

“…A paper-based coupling between BPE and ECL was used for the rapid detection of Hg 2+ . (113) In this original strategy, the divalent cation mediates two thymine-enriched ssDNA probes to form a duplex where the ECL-active [Ru(phen)2dppz] 2+ dye can readily intercalate. This organometallic complex features a dipyridophenazine (dppz) ligand which is responsible for the quenching of luminescence in aqueous media.…”