title: Rapid on-site/in-situ detection of heavy metal ions in environmental water using a structure-switching DNA optical biosensor.
abstract: A structure-switching DNA optical biosensor for rapid on-site/in situ detection of heavy metal ions is reported. Mercury ions (Hg²⁺), highly toxic and ubiquitous pollutants, were selected as model target. In this system, fluorescence-labeled DNA containing T-T mismatch structure was introduced to bind with DNA probes immobilized onto the sensor surface. In the presence of Hg²⁺, some of the fluorescence-labeled DNAs bind with Hg²⁺ to form T-Hg²⁺-T complexes through the folding of themselves into a hairpin structure and dehybridization from the sensor surface, which leads to decrease in fluorescence signal. The total analysis time for a single sample was less than 10 min with detection limit of 1.2 nM. The rapid on-site/in situ determination of Hg²⁺ was readily performed in natural water. This sensing strategy can be extended in principle to other metal ions by substituting the T-Hg²⁺-T complexes with other specificity structures that selectively bind to other analytes.
authors.affiliation: School of Environment and Natural Resources, Renmin University of China, Beijing, China. longf04@ruc.edu.cn
authors.forename: Feng
authors.initials: F
authors.lastname: Long
authors.forename: Anna
authors.initials: A
authors.lastname: Zhu
authors.forename: Hanchang
authors.initials: H
authors.lastname: Shi
authors.forename: Hongchen
authors.initials: H
authors.lastname: Wang
authors.forename: Jingquan
authors.initials: J
authors.lastname: Liu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D004247:DNA / Q000737:chemistry*; D004784:Environmental Monitoring; D006801:Humans; D007477:Ions / Q000032:analysis / Q000737:chemistry*; D008628:Mercury; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000032:analysis / Q000737:chemistry*; D060753:Water Quality / Q000592:standards
chemical_list: D007477:Ions; D019216:Metals, Heavy; D014867:Water; D004247:DNA; D008628:Mercury
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