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 language | English |
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Pages (from-to) | 871-874 |
Number of pages | 4 |
Journal | Biosensors and Bioelectronics |
Volume | 41 |
Issue number | 1 |
DOIs | |
Publication status | Published - 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