(Press-News.org) ANN ARBOR, Mich.—A strip of glass covered in hairy nanoparticles can cheaply and conveniently measure mercury, which attacks the nervous system, and other toxic metals in fluids.
Researchers at the Swiss Federal Institute of Technology (EPFL), Northwestern University and the University of Michigan found that their new method can measure methyl mercury, the most common form of mercury pollution, at unprecedentedly small concentrations. The system, which could test for metal toxins in drinking water and fish, is reported in the current edition of Nature Materials.
Methyl mercury dumped in lakes and rivers accumulates in fish, reaching its highest levels in large, predatory fish such as tuna and swordfish. Young children and pregnant women are advised to avoid eating these fish because mercury can affect the developing brain and nervous system. While metals in drinking water are measured periodically, these measurements say little about migratory fish, including tuna, which may pass through more polluted areas.
"The problem is that current monitoring techniques are too expensive and complex," said researcher Francesco Stellacci, the Constellium Chair holder at EPFL. "With a conventional method, you have to send samples to the laboratory, and the analysis equipment costs several million dollars."
Using the device invented by the Swiss-American team, measuring the mercury levels in water or dissolved fish meat is as simple as dipping a strip of coated glass into the fluid. Metals and metallic molecules, such as methyl mercury, typically become positively charged ions in water. When these ions drift between the hairy nanoparticles, the hairs close up, trapping the pollutant. Passing a current over the strip of glass reveals how many ions are caught in the "nano-velcro." Each ion allows the strip to conduct more electricity.
U-M researchers Hao Jiang and Sharon Glotzer, the Churchill Professor of Chemical Engineering, performed computer simulations that investigated how the nano-velcro traps pollutants. They showed that the hairy nanoparticles are choosey about which ions they capture, confirming that the strips can give reliable measures of specific toxins as demonstrated by the experimental findings of the Swiss group.
"By making detection of pollutants and toxins cheap and easy to do, more testing at the source will lead to safer foods on the dinner table and in kids' lunchboxes," Glotzer said.
The scientists targeted particular pollutants by varying the length of the nano-hairs. This approach is especially successful for methyl mercury, and the device can measure it with record-breaking accuracy, detecting concentrations as low as 600 methyl mercury ions per cubic centimeter of water. Fortunately, that level of precision won't break the bank. The researchers estimate that the coated glass strips could cost less than 10 dollars each, while the measurement device will cost only a few hundred dollars. It could gauge the concentration of metals onsite and within minutes.
The researchers tested their method in Lake Michigan, near Chicago.
"The goal was to compare our measurements to FDA measurements done using conventional methods," Stellacci said.
Despite the industrial activity in the region, mercury levels were extremely low, in agreement with the FDA's analysis. The team also tested a mosquito fish from the Everglades.
"We measured tissue that had been dissolved in acid. The goal was to see if we could detect even very minuscule quantities," said Bartosz Grzybowski, the K. Burgess Professor of Physical Chemistry and Chemical Systems Engineering at Northwestern University, noting the species is too low on the food chain to accumulate high levels of mercury.
The United States Geological Survey reported near-identical results after analyzing the same sample.
"With this technology, it will be possible to conduct tests on a much larger scale in the field, or even in fish before they are put on the market," said researcher Hyewon Kim, MIT student visiting EPFL.
INFORMATION:
Funding for this research came from ENI, via the ENI-MIT Alliance; the U.S. Defense Threat Reduction Agency via a grant to MIT and U-M; and the U.S. Department of Energy via a Nonequilibrium Energy Research Center grant to Northwestern and the U-M.
Sharon Glotzer: http://che.engin.umich.edu/people/glotzer.html
Francesco Stellacci: http://people.epfl.ch/francesco.stellacci
Bartosz Grzybowski: http://dysa.northwestern.edu/bartosz.html
Follow us on Twitter: @UMNewsService
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Baltimore, MD – September 10, 2012 – Researchers at the University of Maryland School of Medicine, who are exploring novel ways to treat serious heart problems in children, have conducted the first direct comparison of the regenerative abilities of neonatal and adult-derived human cardiac stem cells. Among their findings: cardiac stem cells (CSCs) from newborns have a three-fold ability to restore heart function to nearly normal levels compared with adult CSCs. Further, in animal models of heart attack, hearts treated with neonatal stem cells pumped stronger than those ...
LA JOLLA, CA – September 10, 2012 – Over the last decade, metabolomics has emerged as the newest of the "omic" sciences (following genomics and proteomics) to provide comprehensive biochemical information about cellular metabolism. This new field has revealed that many of the chemicals involved in or produced through metabolism are currently unknown, but may play vital and previously unappreciated roles in human health and disease.
A major hurdle in profiling both unknown and known metabolic compounds ("metabolites") has been the scarce amount of reference data. But ...
TORONTO, Sept. 10, 2012—Researchers at St. Michael's Hospital are one step closer to understanding why plaque bursts in coronary arteries and causes heart attacks.
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Dr. Subodh Verma, a cardiac surgeon at St. Michael's, published a paper in the journal Circulation today, describing for the first time how microRNA-145 gene therapy can drastically reduce the severity and progression ...
A new kind of roof-and-attic system field-tested at the Department of Energy's Oak Ridge National Laboratory keeps homes cool in summer and prevents heat loss in winter, a multi-seasonal efficiency uncommon in roof and attic design.
The system improves efficiency using controls for radiation, convection and insulation, including a passive ventilation system that pulls air from the underbelly of the attic into an inclined air space above the roof.
"Heat that would have gone into the house is carried up and out," says Bill Miller of ORNL's Building Envelope Group. "And ...
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Bethesda, MD - The Federation of American Societies for Experimental Biology (FASEB) wrote to all members of the House of Representatives expressing its opposition to the Government Spending Accountability (GSA) Act (HR 4631). While strongly supporting the bill's goal and the desire to ensure that federal agencies are using their resources responsibly and efficiently, FASEB urged Representatives to oppose the bill in its current form. FASEB President Judith S. Bond PhD expressed concern that, "if adopted, HR 4631 would impede the professional development of government ...
PHILADELPHIA — Computers may be getting faster every year, but those advances in computer speed could be dwarfed if their 1's and 0's were represented by bursts of light, instead of electricity.
Researchers at the University of Pennsylvania have made an important advance in this frontier of photonics, fashioning the first all-optical photonic switch out of cadmium sulfide nanowires. Moreover, they combined these photonic switches into a logic gate, a fundamental component of computer chips that process information.
The research was conducted by associate professor Ritesh ...
Teachers and schools that value diversity have a big impact on the academic experiences of Latino immigrant children living in predominantly White communities. That's the finding of a new study by researchers at the University of Kentucky. The study appears in a special section of the September/October 2012 issue of Child Development on children from immigrant families.
Children who had a teacher who valued diversity felt more positively about their ethnicity than children who had a teacher who felt uncomfortable with diversity, the study found.
"This is important ...
Despite often living in poor neighborhoods, immigrant Mexican mothers report few conflicts at home, support from spouses, and strong mental health. At the same time, these moms say they are less likely to read with their young children than native-born White mothers, stemming in part from comparatively low levels of education.
Immigrant Chinese mothers, in contrast, report being more likely than native-born White peers to read with their young children, but more likely to report weaker mental health and greater household conflict.
These are just some of the findings ...
A new study has found that children of immigrants have an advantage over children of native-born Americans when it comes to the transition to adulthood. Among children of similar socioeconomic backgrounds, school conditions, and other characteristics, those born abroad to immigrant parents who came to the United States before their teen years are more likely to follow the best trajectory in academic achievement and school engagement, followed by those born in the United States to immigrant parents.
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