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Wordofa DN, Ramnani P, Tran TT, Mulchandani A. An oligonucleotide-functionalized carbon nanotube chemiresistor for sensitive detection of mercury in saliva. Analyst 2018; 141:2756-60. [PMID: 26902487 DOI: 10.1039/c6an00018e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Divalent mercuric (Hg(2+)) ion and monomethyl mercury (CH3Hg(+)) are two forms of mercury that are known to be highly toxic to humans. In this work, we present a highly selective, sensitive and label-free chemiresistive biosensor for the detection of both, Hg(2+) and CH3Hg(+) ions using DNA-functionalized single-walled carbon nanotubes (SWNTs). The SWNTs were functionalized with the capture oligonucleotide, polyT, using a linker molecule. The polyT was hybridized with polyA to form a polyT:polyA duplex. Upon exposure to mercury ions, the polyT:polyA duplex dehybridizes and a T-Hg(2+)-T duplex is formed. This structure switch leads to the release of polyA from the SWNT surface and correspondingly a change in the resistance of the chemiresistive biosensor is observed, which is used to quantify the mercury ion concentration. The biosensor showed a wide dynamic range of 0.5 to 100 nM for the detection of CH3Hg(+) ions in buffer solution with a sensitivity of 28.34% per log (nM) of CH3Hg(+). Finally, real world application of the biosensor was demonstrated by the detection of Hg(2+) and CH3Hg(+) ions in simulated saliva samples spiked with a known concentration of mercury ions.
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Affiliation(s)
- Dawit N Wordofa
- Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
| | - Pankaj Ramnani
- Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
| | - Thien-Toan Tran
- Department of Bioengineering, University of California, Riverside, California 92521, USA
| | - Ashok Mulchandani
- Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA. and Material Science and Engineering Program, University of California, Riverside, California 92521, USA
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Pirard C, Koppen G, De Cremer K, Van Overmeire I, Govarts E, Dewolf MC, Van De Mieroop E, Aerts D, Biot P, Casteleyn L, Kolossa-Gehring M, Schwedler G, Angerer J, Koch HM, Schindler BK, Castaño A, Esteban M, Schoeters G, Den Hond E, Sepai O, Exley K, Horvat M, Bloemen L, Knudsen LE, Joas R, Joas A, Van Loco J, Charlier C. Hair mercury and urinary cadmium levels in Belgian children and their mothers within the framework of the COPHES/DEMOCOPHES projects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 472:730-740. [PMID: 24333995 DOI: 10.1016/j.scitotenv.2013.11.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 06/03/2023]
Abstract
A harmonized human biomonitoring pilot study was set up within the frame of the European projects DEMOCOPHES and COPHES. In 17 European countries, biomarkers of some environmental pollutants, including urinary cadmium and hair mercury, were measured in children and their mothers in order to obtain European-wide comparison values on these chemicals. The Belgian participant population consisted in 129 school children (6-11 years) and their mothers (≤ 45 years) living in urban or rural areas of Belgium. The geometric mean levels for mercury in hair were 0.383 μg/g and 0.204 μg/g for respectively mothers and children. Cadmium in mother's and children's urine was detected at a geometric mean concentration of respectively 0.21 and 0.04 μg/l. For both biomarkers, levels measured in the mothers and their child were correlated. While the urinary cadmium levels increased with age, no trend was found for hair mercury content, except the fact that mothers hold higher levels than children. The hair mercury content increased significantly with the number of dental amalgam fillings, explaining partially the higher levels in the mothers by their higher presence rate of these amalgams compared to children. Fish or seafood consumption was the other main parameter determining the mercury levels in hair. No relationship was found between smoking status and cadmium or mercury levels, but the studied population included very few smokers. Urinary cadmium levels were higher in both mothers and children living in urban areas, while for mercury this difference was only significant for children. Our small population showed urinary cadmium and hair mercury levels lower than the health based guidelines suggested by the WHO or the JECFA (Joint FAO/WHO Expert Committee on Food Additives). Only 1% had cadmium level slightly higher than the German HBM-I value (1 μg/l for adults), and 9% exceeded the 1 μg mercury/g hair suggested by the US EPA.
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Affiliation(s)
- Catherine Pirard
- CHU of Liege, Laboratory of Clinical, Forensic and Environmental Toxicology, CHU (B35), 4000 Liege, Belgium.
| | - Gudrun Koppen
- Flemish Institute of Technological Research, Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium.
| | - Koen De Cremer
- Scientific Institute of Public Health, Juliette Wytsmanstraat 14, 1050 Brussels, Belgium.
| | - Ilse Van Overmeire
- Scientific Institute of Public Health, Juliette Wytsmanstraat 14, 1050 Brussels, Belgium.
| | - Eva Govarts
- Flemish Institute of Technological Research, Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium.
| | - Marie-Christine Dewolf
- Provincial Institute Hainaut Vigilance Sanitaire - Hainaut Hygiène Publique en (HVS-HPH), Boulevard Sainctelette, 55, 7000 Mons, Belgium.
| | - Els Van De Mieroop
- Provincial Institute for Hygiene (PIH), Boomgaardstraat 22 bus 1, 2600 Antwerpen, Belgium.
| | - Dominique Aerts
- Federal Public Service Health, Food Chain Safety and Environment, Place Victor Horta 40/10, 1060 Brussels, Belgium.
| | - Pierre Biot
- Federal Public Service Health, Food Chain Safety and Environment, Place Victor Horta 40/10, 1060 Brussels, Belgium.
| | - Ludwine Casteleyn
- University of Leuven, Center for Human Genetics, Herestraat 49, 3000 Leuven, Belgium.
| | | | - Gerda Schwedler
- Federal Environment Agency, Corrensplatz 1, 14195 Berlin, Germany.
| | - Jürgen Angerer
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
| | - Holger M Koch
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
| | - Birgit K Schindler
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
| | - Argelia Castaño
- Instituto de Salud Carlos III (ISCIII), Ctra. Majadahonda - Pozuelo, Km. 2, 28220, Madrid, Spain.
| | - Marta Esteban
- Instituto de Salud Carlos III (ISCIII), Ctra. Majadahonda - Pozuelo, Km. 2, 28220, Madrid, Spain.
| | - Greet Schoeters
- Flemish Institute of Technological Research, Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium.
| | - Elly Den Hond
- Flemish Institute of Technological Research, Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium.
| | - Ovnair Sepai
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Oxfordshire OX11 0RQ, United Kingdom.
| | - Karen Exley
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Oxfordshire OX11 0RQ, United Kingdom.
| | - Milena Horvat
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia.
| | - Louis Bloemen
- Environmental Health Science International, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
| | - Lisbeth E Knudsen
- University of Copenhagen, Department of Public Health, Øster Farimagsgade 5, 1353 København, Denmark.
| | - Reinhard Joas
- BiPRO GmbH, Grauertstrasse 12, 81545 Munich, Germany.
| | - Anke Joas
- BiPRO GmbH, Grauertstrasse 12, 81545 Munich, Germany.
| | - Joris Van Loco
- Scientific Institute of Public Health, Juliette Wytsmanstraat 14, 1050 Brussels, Belgium.
| | - Corinne Charlier
- CHU of Liege, Laboratory of Clinical, Forensic and Environmental Toxicology, CHU (B35), 4000 Liege, Belgium.
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