Document Type

Journal Article

Department/Unit

Department of Chemistry

Title

Label-free detection of sub-nanomolar lead(II) ions in aqueous solution using a metal-based luminescent switch-on probe

Language

English

Abstract

A label-free oligonucleotide-based luminescent switch-on assay has been developed for the selective detection of sub-nanomolar Pb2+ ions in aqueous solution and real water samples. An iridium(III) complex was employed as a G-quadruplex specific luminescent probe and a guanine rich DNA (PS2.M, 5'-GTG3TAG3CG3T2G2-3') was employed as recognition unit for Pb2+ ions. The PS2.M exists in a single-stranded conformation in the absence of Pb2+ ions, and the weak binding of the iridium(III) probe to ssDNA results in a weak luminescence signal. Upon binding to Pb2+ ions, the single-stranded DNA sequence (PS2.M) is induced into a G-quadruplex conformation, which greatly enhances the luminescence emission of the iridium(III) probe. The assay can detect Pb2+ ions in aqueous media with a limit of detection of 600pM. It also exhibits good selectivity for Pb2+ ions over other heavy metal ions. Furthermore, the application of the assay for the detection of Pb2+ ions in spiked river water samples has been demonstrated. © 2012 Elsevier B.V.

Keywords

G-quadruplex, Iridium(III) complex, Label-free detection, Lead(II) ion, Luminescent probe

Publication Date

2013

Source Publication Title

Biosensors and Bioelectronics

Volume

41

Start Page

871

End Page

874

Publisher

Elsevier

DOI

10.1016/j.bios.2012.08.060

Link to Publisher's Edition

http://dx.doi.org/10.1016/j.bios.2012.08.060

ISSN (print)

09565663

ISSN (electronic)

18734235

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