G-quadruplex-selective iridium(III) complex as a novel electrochemiluminescence probe for switch-on assay of double-stranded DNA

Shujie Wu, Songen Wang, Zongbing Li, Chun Wu, Dik-Lung Ma*, Xiangmin Miao*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

3 Citations (Scopus)


In this work, we synthesized an iridium(III) complex and studied its selective ability to interact with a specific G-quadruplex DNA sequence (GTGGGTAGGGCGGGTTGG). Results showed that the iridium(III) complex exhibits high selectivity for the G-quadruplex DNA and could be used as an efficient electrochemiluminescence (ECL) probe in a switch-on assay format for the detection of double-stranded DNA (dsDNA). To construct the assay, a hairpin-structured capture probe (CP) which was modified by thiol at its 3′ end and contained the G-quadruplex sequence at its 5′ end was firstly immobilized on a gold electrode. Upon the specific recognition of the dsDNA sequence with the corresponding CP, the hairpin structure of the CP was opened to free G-quadruplex sequence, forming the G-quadruplex structure with the assistance of K+. Then, the iridium(III) complex was able to specifically interact with the G-quadruplex to produce an obvious ECL signal that was proportional to the dsDNA concentration. Notably, this iridium(III) complex/G-quadruplex-based strategy was universal and was not limited to the analysis of DNA using specific sequences, thus opening a new avenue for the application of the G-quadruplex-selective iridium(III) complex in the field of ECL.

Original languageEnglish
Pages (from-to)3755–3763
Number of pages9
JournalAnalytical and Bioanalytical Chemistry
Issue number13
Early online date9 Apr 2022
Publication statusPublished - May 2022

Scopus Subject Areas

  • Analytical Chemistry
  • Biochemistry

User-Defined Keywords

  • Capture probe
  • Electrochemiluminescence assay
  • G-quadruplex
  • Iridium(III) complex
  • Target dsDNA


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