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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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Scheme of the DNAzyme-based electrochemical sensor. Upon addition of Pb2+, the DNA2 is cleaved, which gives more freedom to MB-labeled DNA1. Reprinted with permission from [119]. Copyright 207 American Chemical Society.
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biosensors-05-00241-f015: Scheme of the DNAzyme-based electrochemical sensor. Upon addition of Pb2+, the DNA2 is cleaved, which gives more freedom to MB-labeled DNA1. Reprinted with permission from [119]. Copyright 207 American Chemical Society.

Mentions: DNAzymes are DNA sequences having the property to catalyze specific chemical and biological reactions, such as cleavage of the ribonucleic acid target. Some DNAzymes use divalent metal ion as cofactors; in the presence of this metal ion, the substrate is irreversibly cleaved into two fragments at the cleavage site [114]. Recently, DNAzymes have been used for the detection of lead [115,116,117] and copper [118]. Xiao et al. [119] have proposed a very elegant method for lead detection based on the use of a surface-immobilized, methylene-blue modified DNAzyme assembly (Figure 15). Without Pb2+, DNAzyme adopts a hairpin structure with the methylene blue away from the surface. In the presence of Pb2+, the substrate strand was cleaved. Therefore, the released enzyme strand become more flexible and facilitates the electron transfer between methylene blue and the electrode. The signal is proportional to the concentration of Pb2+ and the detection limit is 300 nM (Figure 16A,B).


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

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

Scheme of the DNAzyme-based electrochemical sensor. Upon addition of Pb2+, the DNA2 is cleaved, which gives more freedom to MB-labeled DNA1. Reprinted with permission from [119]. Copyright 207 American Chemical Society.
© Copyright Policy
Related In: Results  -  Collection

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

biosensors-05-00241-f015: Scheme of the DNAzyme-based electrochemical sensor. Upon addition of Pb2+, the DNA2 is cleaved, which gives more freedom to MB-labeled DNA1. Reprinted with permission from [119]. Copyright 207 American Chemical Society.
Mentions: DNAzymes are DNA sequences having the property to catalyze specific chemical and biological reactions, such as cleavage of the ribonucleic acid target. Some DNAzymes use divalent metal ion as cofactors; in the presence of this metal ion, the substrate is irreversibly cleaved into two fragments at the cleavage site [114]. Recently, DNAzymes have been used for the detection of lead [115,116,117] and copper [118]. Xiao et al. [119] have proposed a very elegant method for lead detection based on the use of a surface-immobilized, methylene-blue modified DNAzyme assembly (Figure 15). Without Pb2+, DNAzyme adopts a hairpin structure with the methylene blue away from the surface. In the presence of Pb2+, the substrate strand was cleaved. Therefore, the released enzyme strand become more flexible and facilitates the electron transfer between methylene blue and the electrode. The signal is proportional to the concentration of Pb2+ and the detection limit is 300 nM (Figure 16A,B).

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