A facile “turn-on” fluorescent method with high sensitivity for Hg2+ detection using magnetic Fe3O4 nanoparticles and hybridization chain reactions
2016
Lv, Xiaoxiao | Wu, Wenchen | Niu, Chenggang | Huang, Dawei | Wang, Xiaoyu | Zhang, Xuegang
In this manuscript, the authors molecularly engineered a hybridization chain reactions (HCRs) based probe on magnetic Fe₃O₄ nanoparticles for the sensitive detection of Hg²⁺. 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 Hg²⁺, the report probes were stable as molecular beacons in solution. In the presence of Hg²⁺, the T-rich capture probes and report probes will hybridize into double-helical DNA domains with the aid of T–Hg²⁺–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 Hg²⁺ 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.
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