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Simple and signal-off electrochemical biosensor for mercury(II) based on thymine-mercury-thymine hybridization directly on graphene
journal contribution
posted on 2015-07-10, 00:00 authored by Y Zhang, J Xie, Y Liu, P Pang, L Feng, H O N G B I N Wang, Z Wu, Wenrong YangWenrong YangAbstract A simple, signal-off and reusable electrochemical biosensor was developed for sensitive and selective detection of mercury(II) based on thymine-mercury(II)-thymine (T-Hg2+-T) complex and the remarkable difference in the affinity of graphene with double strand DNA (ds-DNA) and single strand DNA (ss-DNA). Our system was composed of ferrocene-tagged probe DNA and graphene. Due to the noncovalent assembly, the ferrocene-tagged probe ss-DNA was immobilized on the surface of graphene nanosheets directly and employed to amplify the electrochemical signal. In the presence of Hg2+, the ferrocene-labeled T-rich DNA probe hybridized with target probe to form ds-DNA via the Hg2+-mediated coordination of T-Hg2+-T base pairs. As a result, the duplex DNA complex kept away from the graphene surface due to the weak affinity of graphene and ds-DNA, and the redox current decreased substantially. Meanwhile, the graphene decorated GCE surface was released for the reusability. Under the optimal conditions, the proposed sensor showed a linear concentration range from 25 pM to 10 μM with a detection limit of 5 pM for Hg2+ detection. The strategy afforded exquisite selectivity for Hg2+ against other metal ions in real environmental samples.
History
Journal
Electrochimica actaVolume
170Pagination
210 - 217Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0013-4686eISSN
1873-3859Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2015, ElsevierUsage metrics
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