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

Hong Zhang He, Ka Ho Leung, Hui Yang, Daniel Shiu-Hin Chan, Chung Hang Leung, Jun Zhou, Anne Bourdoncle, Jean Louis Mergny, Edmond Dik Lung MA*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)871-874
Number of pages4
JournalBiosensors and Bioelectronics
Volume41
Issue number1
DOIs
Publication statusPublished - 15 Mar 2013

Scopus Subject Areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

User-Defined Keywords

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

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