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.
The state has sent National Guard troops to the town of Pahoa to assist with a road block and security.
Researchers had tried for 23 years to connect this piece of metal to Amelia Earhart's disappearance. They finally think they've proven it was part of her plane.
Michelangelo painted the ceiling of the Sistine Chapel by the light of the sun coming through small windows, and now 450 years after his death, his masterpieces are being seen in a whole new light provided by 7,000 LEDs. The chapel is also getting a new ventilation system. Allen Pizzey reports.
Reports that a passenger photographed a rainbow from her plane are mistaken. The colours are caused by polarisation
Jiri Bruthans created this pillar with simulated salt weathering; in nature (like at Bryce Canyon, below), factors like frost and rain also shape the landscape. Courtesy of Jiri Bruthans Getty Aa the story goes, the iconic spires in Utah's Bryce Canyon National Park once were human-animal “legend people,” until an angry coyote god turned them […]
The discovery of a third type of light associated with dark matter could strengthen the case that we are seeing a signal of the mysterious stuff
The flow, which began at Mount Kilauea in June, threatens to take out dozens of homes on the Big Island.
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"