A Luminescent Cocaine Detection Platform Using a Split G-Quadruplex-Selective Iridium(III) Complex and a Three-Way DNA Junction Architecture.
In this study, a series of 10 in-house cyclometalated iridium(III) complexes bearing different auxiliary ligands were tested for their selectivity toward split G-quadruplex in order to construct a label-free switch-on cocaine detection platform employing a three-way junction architecture and a G-quadruplex motif as a signal output unit. Through two rounds of screening, we discovered that the iridium(III) complex 7 exhibited excellent selectivity toward the intermolecular G-quadruplex motif. A detection limit as low as 30 nM for cocaine can be achieved by this sensing approach with a linear relationship between luminescence intensity and cocaine concentration established from 30 to 300 nM. Furthermore, this sensing approach could detect cocaine in diluted oral fluid. We hope that our simple, signal-on, label-free oligonucleotide-based sensing method for cocaine using a three-way DNA junction architecture could act as a useful platform in bioanalytical research.
Department of Chemistry, Hong Kong Baptist University , Hong Kong, China.|Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University , Hong Kong, China.
Dik-Lung
DL
Ma
Department of Chemistry, Hong Kong Baptist University , Hong Kong, China.
Modi
M
Wang
Department of Chemistry, Hong Kong Baptist University , Hong Kong, China.
Bingyong
B
He
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Macao, China.
Chao
C
Yang
Department of Chemistry, Hong Kong Baptist University , Hong Kong, China.
Wanhe
W
Wang
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Macao, China.
Chung-Hang
CH
Leung
D001483:Base Sequence; D001681:Biological Assay / Q000379:methods*; D003042:Cocaine / Q000032:analysis*; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D007495:Iridium / Q000737:chemistry*; D049449:Luminescence; D008969:Molecular Sequence Data; D012996:Solutions; D013050:Spectrometry, Fluorescence
D012996:Solutions; D007495:Iridium; D004247:DNA; D003042:Cocaine
G-quadruplex; cocaine; iridium(III) complex; label-free; three-way junction