title: A facile "turn-on" fluorescent method with high sensitivity for Hg(2+) detection using magnetic Fe3O4 nanoparticles and hybridization chain reactions.
abstract: In this manuscript, the authors molecularly engineered a hybridization chain reactions (HCRs) based probe on magnetic Fe3O4 nanoparticles for the sensitive detection of Hg(2+). The sensing system comprised three probes: capture probe H1, report probe H2, and report probe H3. The capture probe was modified on the surface of magnetic Fe3O4 nanoparticles. The report probes were labeled with fluorescein isothiocyanate (FITC). Without Hg(2+), the report probes were stable as molecular beacons in solution. In the presence of Hg(2+), the T-rich capture probes and report probes will hybridize into double-helical DNA domains with the aid of T-Hg(2+)-T coordination chemistry. Trigged by this reaction, more molecular beacons open and form a super tandem structure. Herein, the fluorescence signal was magnified by capturing more report probes. Separating the target and captured report probes from reaction solution was benefit to decrease the background signal and interference from other metal ions. The detection limit of this method was about 0.36nM, which is much lower than the regulations of World Health Organization and U.S. Environmental Protection Agency on Hg(2+) in drink water. This proposed sensing strategy also showed favorable selectivity over other common metal ions. In addition, it has good practicability in real water samples.
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Lv
authors.affiliation: Department of Orthopaedics, Heji Hospital, Changzhi Medical College, Shanxi 046000, China.
authors.forename: Wenchen
authors.initials: W
authors.lastname: Wu
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China. Electronic address: cgniu@hnu.edu.cn.
authors.forename: Chenggang
authors.initials: C
authors.lastname: Niu
authors.affiliation: South China Institute of Environmental Sciences, Ministry of Environmental Protection of PRC, Guangzhou 510655, China. Electronic address: huangdawei@scies.org.
authors.forename: Dawei
authors.initials: D
authors.lastname: Huang
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082, China.
authors.forename: Xuegang
authors.initials: X
authors.lastname: Zhang
mesh_terms: D015342:DNA Probes / Q000737:chemistry / Q000235:genetics*; D019793:Fluorescein / Q000737:chemistry; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D017879:Isothiocyanates / Q000737:chemistry; D007700:Kinetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D009693:Nucleic Acid Hybridization / Q000379:methods*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
chemical_list: D015342:DNA Probes; D017879:Isothiocyanates; D058185:Magnetite Nanoparticles; C037152:isothiocyanic acid; D008628:Mercury; D019793:Fluorescein
keywords: Fluorescence; Hg(2+); Hybridization chain reactions; Magnetic Fe(3)O(4) nanoparticles