Journal
ANALYTICA CHIMICA ACTA
Volume 956, Issue -, Pages 63-69Publisher
ELSEVIER
DOI: 10.1016/j.aca.2016.12.021
Keywords
Uranyl ion; DNAzyme; Colorimetric biosensor; Magnetic beads; DNA hybridization chain reaction
Categories
Funding
- NSFC [21377025, 21677034]
- Fujian Provincial Department of Science and Technology [2014Y0042, 2016J01385]
- Program for Changjiang Scholars and Innovative Research Team in University [IRT-15R11]
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A novel colorimetric biosensor, which employs DNAzyme-functionalized magnetic beads (MBs) as recognition probe, enzyme-assisted catalytic oxidation of TMB (3,3',5,5'-tetramethylbenzidine sulfate) as signal and DNA hybridization chain reaction as amplification strategy, has been developed for detecting trace uranyl ion (UO22+ in seafood and aqueous environment with high sensitivity and specificity. We demonstrated that UO22+ can specifically cleave DNAzyme immobilized on MBs surface to release a short single-strand DNA (primer), and the released primer trigger DNA hybridization chain reaction to form a long one dimensional DNA concatamer on the MBs surface. The resulting long DNA concatamer could capture a large amount of HRP to generate the one UO22+-to-multiple HRP amplification effect. Upon the addition of TME-H2O2 solution, the HRP-tagged DNA concatamer-MBs conjugates could catalyze the H2O2-mediated oxidation of TMB, and thus results in a color change from colorless to blue in solution. This provided a sensitive and selective sensing platform for the visual or colorimetric detection of UO22+. The proposed biosensor has high sensitivity and strong anti-interference capability, it can be used to detect as low as 2.5 ppb (9.25 nM) of UO22+ by naked-eye observation and 0.09 ppb (0.33 nM) of UO22+ by UV-visible spectrometry with no interference of other ions and a RSD <= 6% (n = 5). With the help of this method, we have successfully determined trace UO22+ in fish muscle and river water with a recovery of 93 -106%. High sensitivity and specificity, as well operation convenience, low cost and strong resistibility to the matrix, which makes our method a potential approach for the on-site detection of UO22+ in seafood and aqueous environment. (C) 2016 Elsevier B.V. All rights reserved.
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