Researchers at the National Institute of Standards and Technology (NIST) have provided evidence in the laboratory that single-wall carbon nanotubes (SWCNTs) may help protect DNA molecules from damage by oxidation. In nature, oxidation is a common chemical process in which a reactive chemical removes electrons from DNA and may increase the chance for mutations in cells. More studies are needed to see if the in vitro protective effect of nanotubes reported in the laboratory also occurs in vivo, that is, within a living organism.
"Our findings don't tell us whether carbon nanotubes are good or bad for people and the environment," says Elijah Petersen, one of the authors of the study. "However, the results do help us better understand the mechanisms by which nanotubes might interact with biomolecules."
Single-wall carbon nanotubes—tiny hollow rods that are one-atom-thick sheets of graphene rolled into cylinders 10,000 times smaller in diameter than a human hair—are prized for their extraordinary optical, mechanical, thermal and electronic properties. They are being used to produce lightweight and extremely strong materials, enhance the capabilities of devices such as sensors, and provide a novel means of delivering drugs with great specificity. However, as carbon nanotubes become increasingly incorporated into consumer and medical products, the public concern about their potential environmental, health and safety (EHS) risks has grown. Scientifically determining the level of risk associated with the carbon nanotubes has been challenging, with different studies showing conflicting results on cellular toxicity. One of the components lacking in these studies is an understanding of what physically happens at the molecular level.
In a recent paper,* NIST researchers investigated the impact of ultrasonication on a solution of DNA fragments known as oligomers in the presence and absence of carbon nanotubes. Ultrasonication is a standard laboratory technique that uses high-frequency sound waves to mix solutions, break open cells or process slurries. The process can break water molecules into highly reactive agents such as hydroxyl radicals and hydrogen peroxide that are similar to the oxidative chemicals that commonly threaten mammalian cell DNA, although the experimental levels from sonication are much greater than those found naturally within cells. "In our experiment, we were looking to see if the nanotubes enhanced or deterred oxidative damage to DNA," Petersen says.
Contrary to the expectation that carbon nanotubes will damage biomolecules they contact, the researchers found that overall levels of accumulated DNA damage were significantly reduced in the solutions with nanotubes present. "This suggests that the nanotubes may provide a protective effect against oxidative damage to DNA," Petersen says.
A possible explanation for the surprising result, Petersen says, is that the carbon nanotubes may act as scavengers, binding up the oxidative species in solution and preventing them from interacting with DNA. "We also saw a decrease in DNA damage when we did ultrasonication in the presence of dimethyl sulfoxide (DMSO), a chemical compound known to be a hydroxyl radical scavenger," Petersen says.
Petersen says that a third experiment where ultrasonication was performed in the presence of DMSO and SWCNTs at the same time produced an additive effect, reducing the DNA damage levels more significantly than either treatment alone.
* E.J. Petersen, X. Tu, M. Dizdaroglu, M. Zheng and B.C. Nelson. Protective roles of single-wall carbon nanotubes in ultrasonication-induced DNA base damage. Small (2012), DOI: 10/1002/smll.201201217.
National Institute of Standards and Technology (NIST): http://www.nist.gov
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Written 20 years ago, the first algorithm to tap into the ultra-fast potential of quantum computing has been run on a real machine at long last
Shirley Corriher, author of Cookwise: The Hows and Whys of Successful Cooking, has tips on taking the bitter bite out of coffee, and holding onto cabbage's red hue while it's in the pan.
Data originally taken for another reason weaken the case for "dark photons"
Kip Thorne looks into the black hole he helped create and thinks, “Why, of course. That's what it would do.” This particular black hole is a simulation of unprecedented accuracy. It appears to spin at nearly the speed of light, dragging bits of the universe along with it. (That's gravity for you; relativity is superweird.) In theory it was once a star, but instead of fading or exploding, it collapsed like a failed soufflé into a tiny point of inescapable singularity. A glowing ring orbiting the spheroidal maelstrom seems to curve over the top and below the bottom simultaneously.
Apeel Sciences hopes its products, which use natural methods to fend off pests and oxidization, can markedly reduce the amount of produce wasted because of spoilage.
Francis Halzen’s amazing experiment heralds the beginning of a new era in astronomy
First direct detection of dark matter, thought to make up most of the matter in the universe, would be a historic breakthrough
Geologists, climate scientists, ecologists and a lawyer gather in Berlin for talks on whether to rename age of human lifeHumanitys terrifying impact on Earth justifies new Anthropocene epoch
This month in Italy, three judges have a chance to undo the Kafkaesque nightmare that has ensnared some of the country’s top scientists for almost five years. So far it looks doubtful they will. In 2012, seven scientists and engineers were convicted of manslaughter for things they said and did not say in the days
Turkey's eternal fires have remained burning for thousands of years but now the source of the methane that fuels them has been found