title: Magnetic beads-based DNA hybridization chain reaction amplification and DNAzyme recognition for colorimetric detection of uranyl ion in seafood.
abstract: 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 TMB-H2O2solution, 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.
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China; College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
authors.forename: Lian
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Mo
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
authors.forename: LiangJun
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China. Electronic address: fengfu@fzu.edu.cn.
authors.forename: FengFu
authors.initials: F
authors.lastname: Fu
mesh_terms: D015374:Biosensing Techniques; D003124:Colorimetry; D021881:DNA, Catalytic; D006861:Hydrogen Peroxide; D017747:Seafood / Q000032:analysis*; D014501:Uranium / Q000032:analysis*
chemical_list: D021881:DNA, Catalytic; D014501:Uranium; D006861:Hydrogen Peroxide
keywords: Colorimetric biosensor; DNA hybridization chain reaction; DNAzyme; Magnetic beads; Uranyl ion