Amplified colorimetric detection of mercuric ions through autonomous assembly of G-quadruplex DNAzyme nanowires.
An amplified colorimetric detection of Hg(2+) is proposed by combining T-Hg(2+)-T base pairs and hybridization chain reaction (HCR). Two hairpins consisting of three-fourths and one-fourth of the horseradish peroxidase (HRP)-mimicking DNAzyme in inactive configuration are used as functional elements. In the presence of Hg(2+), one of the hairpins is opened by an assistant probe with the help of T-Hg(2+)-T base pairs and this triggers an autonomous cross-opening of the two hairpins using the strand displacement principle, resulting in the formation of DNA nanowires consisting of numerous reunited Q-quadruplex DNAzyme units. The resulting catalytically active hemin/G-quadruplex HRP-mimicking DNAzymes catalyze the oxidation of ABTS(2-) by H2O2 into a green-colored cationic radical ABTS(•+) for the colorimetric readout. This "turn-on" sensing system enables the high sensitive and selective detection of aqueous Hg(2+) with a detection limit of 9.7 pM.
Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, and Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
Yanli
Y
Hao
Qingquan
Q
Guo
Hanyin
H
Wu
Liangqia
L
Guo
Liangshuang
L
Zhong
Jing
J
Wang
Tianran
T
Lin
FengFu
F
Fu
Guonan
G
Chen
D015374:Biosensing Techniques; D003124:Colorimetry; D021881:DNA, Catalytic / Q000737:chemistry; D054856:G-Quadruplexes; D006861:Hydrogen Peroxide; D007477:Ions / Q000737:chemistry / Q000302:isolation & purification*; D057230:Limit of Detection; D008628:Mercury / Q000737:chemistry / Q000302:isolation & purification*; D053770:Nanowires / Q000737:chemistry
D021881:DNA, Catalytic; D007477:Ions; D006861:Hydrogen Peroxide; D008628:Mercury
ABTS; DNAzyme; G-quadruplex; Hemin; Mercury