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Modified electrodes used for electrochemical detection of metal ions in environmental analysis.

March G, Nguyen TD, Piro B - Biosensors (Basel) (2015)

Bottom Line: Many efforts have been made to develop sensors for monitoring heavy metals in the environment.The first part of this review will be dedicated to stripping voltammetry techniques, on unmodified electrodes (mercury, bismuth or noble metals in the bulk form), or electrodes modified at their surface by nanoparticles, nanostructures (CNT, graphene) or other innovative materials such as boron-doped diamond.Special attention will be paid to strategies using biomolecules (DNA, peptide or proteins), enzymes or whole cells.

View Article: PubMed Central - PubMed

Affiliation: Klearia, route de Nozay, Marcoussis 91460, France. gregory.march@free.fr.

ABSTRACT
Heavy metal pollution is one of the most serious environmental problems, and regulations are becoming stricter. Many efforts have been made to develop sensors for monitoring heavy metals in the environment. This review aims at presenting the different label-free strategies used to develop electrochemical sensors for the detection of heavy metals such as lead, cadmium, mercury, arsenic etc. The first part of this review will be dedicated to stripping voltammetry techniques, on unmodified electrodes (mercury, bismuth or noble metals in the bulk form), or electrodes modified at their surface by nanoparticles, nanostructures (CNT, graphene) or other innovative materials such as boron-doped diamond. The second part will be dedicated to chemically modified electrodes especially those with conducting polymers. The last part of this review will focus on bio-modified electrodes. Special attention will be paid to strategies using biomolecules (DNA, peptide or proteins), enzymes or whole cells.

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Related in: MedlinePlus

(A) Poly-T oligonucleotides tethered on one end on the electrode surface, and labeled on the other end with a ferrocenyl moiety. Upon addition of Hg2+, poly-T strands become rigid, drawing Fc away from the surface. Reprinted with permission from [110]. Copyright 2009 American Chemical Society; (B) DNA strand carrying a ferrocenyl tag at one end and immobilized on a gold electrode at its other end by a SH group. Under this conformation, the ferrocene is far from the surface and no current flows. A hairpin structure is induced if Hg2+ are present, by association between two T bases, which brings the Fc label close to the electrode surface. The sensor can be regenerated by simply unfolding the ferrocene-labeled DNA in 10 µM cysteine. Reproduced from [111] with permission of The Royal Society of Chemistry.
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biosensors-05-00241-f014: (A) Poly-T oligonucleotides tethered on one end on the electrode surface, and labeled on the other end with a ferrocenyl moiety. Upon addition of Hg2+, poly-T strands become rigid, drawing Fc away from the surface. Reprinted with permission from [110]. Copyright 2009 American Chemical Society; (B) DNA strand carrying a ferrocenyl tag at one end and immobilized on a gold electrode at its other end by a SH group. Under this conformation, the ferrocene is far from the surface and no current flows. A hairpin structure is induced if Hg2+ are present, by association between two T bases, which brings the Fc label close to the electrode surface. The sensor can be regenerated by simply unfolding the ferrocene-labeled DNA in 10 µM cysteine. Reproduced from [111] with permission of The Royal Society of Chemistry.

Mentions: Thymine bases (T) can interact with Hg2+ to form T-Hg-T structures which are even more stable than the Watson-Crick adenine-thymine pair [105]. Various electrochemical sensors for Hg2+ detection have been proposed using this approach [106,107,108,109]. For example, Liu et al. [110] have developed a simple strategy using poly-T oligonucleotides labeled with a ferrocenyl group and immobilized on the electrode surface via self-assembly of the terminal thiol moiety (Figure 14A). In the presence of Hg2+, a pair of poly-T oligonucleotides can cooperatively coordinate with Hg2+, which triggers a conformational reorganization of the poly-T oligonucleotides from flexible single strands to relatively rigid duplex-like complexes, thus drawing the ferrocenyl tags away from the electrode with a substantial decrease of the redox current.


Modified electrodes used for electrochemical detection of metal ions in environmental analysis.

March G, Nguyen TD, Piro B - Biosensors (Basel) (2015)

(A) Poly-T oligonucleotides tethered on one end on the electrode surface, and labeled on the other end with a ferrocenyl moiety. Upon addition of Hg2+, poly-T strands become rigid, drawing Fc away from the surface. Reprinted with permission from [110]. Copyright 2009 American Chemical Society; (B) DNA strand carrying a ferrocenyl tag at one end and immobilized on a gold electrode at its other end by a SH group. Under this conformation, the ferrocene is far from the surface and no current flows. A hairpin structure is induced if Hg2+ are present, by association between two T bases, which brings the Fc label close to the electrode surface. The sensor can be regenerated by simply unfolding the ferrocene-labeled DNA in 10 µM cysteine. Reproduced from [111] with permission of The Royal Society of Chemistry.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493548&req=5

biosensors-05-00241-f014: (A) Poly-T oligonucleotides tethered on one end on the electrode surface, and labeled on the other end with a ferrocenyl moiety. Upon addition of Hg2+, poly-T strands become rigid, drawing Fc away from the surface. Reprinted with permission from [110]. Copyright 2009 American Chemical Society; (B) DNA strand carrying a ferrocenyl tag at one end and immobilized on a gold electrode at its other end by a SH group. Under this conformation, the ferrocene is far from the surface and no current flows. A hairpin structure is induced if Hg2+ are present, by association between two T bases, which brings the Fc label close to the electrode surface. The sensor can be regenerated by simply unfolding the ferrocene-labeled DNA in 10 µM cysteine. Reproduced from [111] with permission of The Royal Society of Chemistry.
Mentions: Thymine bases (T) can interact with Hg2+ to form T-Hg-T structures which are even more stable than the Watson-Crick adenine-thymine pair [105]. Various electrochemical sensors for Hg2+ detection have been proposed using this approach [106,107,108,109]. For example, Liu et al. [110] have developed a simple strategy using poly-T oligonucleotides labeled with a ferrocenyl group and immobilized on the electrode surface via self-assembly of the terminal thiol moiety (Figure 14A). In the presence of Hg2+, a pair of poly-T oligonucleotides can cooperatively coordinate with Hg2+, which triggers a conformational reorganization of the poly-T oligonucleotides from flexible single strands to relatively rigid duplex-like complexes, thus drawing the ferrocenyl tags away from the electrode with a substantial decrease of the redox current.

Bottom Line: Many efforts have been made to develop sensors for monitoring heavy metals in the environment.The first part of this review will be dedicated to stripping voltammetry techniques, on unmodified electrodes (mercury, bismuth or noble metals in the bulk form), or electrodes modified at their surface by nanoparticles, nanostructures (CNT, graphene) or other innovative materials such as boron-doped diamond.Special attention will be paid to strategies using biomolecules (DNA, peptide or proteins), enzymes or whole cells.

View Article: PubMed Central - PubMed

Affiliation: Klearia, route de Nozay, Marcoussis 91460, France. gregory.march@free.fr.

ABSTRACT
Heavy metal pollution is one of the most serious environmental problems, and regulations are becoming stricter. Many efforts have been made to develop sensors for monitoring heavy metals in the environment. This review aims at presenting the different label-free strategies used to develop electrochemical sensors for the detection of heavy metals such as lead, cadmium, mercury, arsenic etc. The first part of this review will be dedicated to stripping voltammetry techniques, on unmodified electrodes (mercury, bismuth or noble metals in the bulk form), or electrodes modified at their surface by nanoparticles, nanostructures (CNT, graphene) or other innovative materials such as boron-doped diamond. The second part will be dedicated to chemically modified electrodes especially those with conducting polymers. The last part of this review will focus on bio-modified electrodes. Special attention will be paid to strategies using biomolecules (DNA, peptide or proteins), enzymes or whole cells.

Show MeSH
Related in: MedlinePlus