Dangerous nanotubes: The long, multiwalled carbon nanotubes shown here can lead to inflammation, lesions, and cancer when they come in contact with mesothelial tissues that surround organs in the body, according to new studies performed on mice. (Scale bar is 20 micrometers.)
Ken Donaldson, University of Edinburgh
New studies suggest that long carbon nanotubes behave like asbestos.
Certain types of carbon nanotubes could cause the same health problems as asbestos, according to the results of two recent studies. In one, published yesterday, tests in mice showed that long and straight multiwalled carbon nanotubes cause the same kind of inflammation and lesions in the type of tissues that surround the lungs that is caused by asbestos. The other study, also done in mice, showed that similar carbon nanotubes eventually led to cancerous tumors.
Carbon nanotubes, tube-shaped carbon molecules just tens of nanometers in diameter, have excellent electronic and mechanical properties that make them attractive for a number of applications. They have already been incorporated into some products, such as tennis rackets and bicycles, and eventually they could be used in a wide variety of applications, including medical therapies, water purification, and ultrafast and compact computer chips. "It's a material that's got many unique characteristics," says Andrew Maynard, a coauthor of one of the studies, which appears in the current issue of Nature Nanotechnology. "But of course nothing comes along like this that is completely free from risk."
Carbon nanotubes that are straight and 20 micrometers or longer in length--qualities that are well suited for composite materials used in sports equipment--resemble asbestos fibers. This has long led many experts to suggest that these carbon nanotubes might pose the same health risks as asbestos, a fire-resistant material that can cause mesothelioma, a cancer of a type of tissue surrounding the lungs. But until now, strong scientific evidence for this theory was lacking.
The new studies partially confirm the carbon nanotubes' similarity to asbestos by showing that long, straight carbon nanotubes injected into mesothelial tissues in mice cause the sort of lesions and inflammation that also develop as a result of asbestos. Such reactions are a strong indicator that cancer will develop with chronic exposure. One of the studies, which appeared in the Journal of Toxicological Study and was done by researchers at Japan's National Institute of Health Sciences, also showed actual cancerous tumors. The Nature Nanotechnology study was done primarily by researchers in the United Kingdom at the University of Edinburgh and elsewhere.
What isn't known is whether, during nanotubes' manufacture, use, and disposal, they can become airborne and be inhaled in sufficient quantities to cause problems. Indeed, earlier work has shown that it is actually difficult to get carbon nanotubes airborne, since they tend to clump together, says Maynard, the chief science advisor for the Project on Emerging Nanotechnologies, at the Woodrow Wilson Center for Scholars, in Washington, DC. He says that this could decrease the chance that they will be inhaled. He adds that further research is needed to confirm this.
A fast screening method could help separate the good from the bad.
New composites could lead to better food packaging, and to lighter car and airplane parts.
Updated Link to Nature Nanotechnology Study
The link in the article to the study published in Nature Nanotechnology is no longer current. The study can be accessed at: http://www.nature.com/nnano/journal/v3/n7/abs/nnano.2008.111.html
Image was of Curly not Straight MWCNT
Because I worked in a factory making Multi-Walled curly CNT you can imagine how I've been going nuts for 2 years since this annoying study was made because nobody knows what they are talking about when they say "Straight and Long" nanotubes especially when they show images of the clumped spaghetti that MWCNT is normally manufactured as before refining. I discussed this with Professor Donaldson and he said it isn't even possible in this day and age to examine animal tissue to see if long and curly CNT is in it!!
This is because the curly spaghetti CNT will get sliced into smaller portions when microscopic slides are produced.
Nobody breathes the refined stuff because it is too expensive, but the raw stuff out of the ovens is mostly curly spaghetti that clumps.
It DOES however remain airborne for several hours after a batch of tubes is produced and the oven doors are opened (before 2003 ovens just opened and released a plume of black dust into the offices where the tubes were produced - yes, carbon nanotube factories were usually offices with secretaries and marketing personnel in the same room as the oven.
So what is it? Is that an accurate photo in the article of the type of long "straight" CNT that causes cancer? Because it looked darned curly and clumped to me. That is the stuff I breathed for 2 months.
FURTHERMORE: Where are the darned blood tests that can help people like me who worked in CNT factories to test if there is any kind of inflammation in the mesothelia??
I have heard there is a MesoMark test for Osteopontin that will detect early cancer growth...but what about something that will detect heavy contamination of the mesothelia 10 years before any cancer develops?
These questions should not be rocket science.
And where was OSHA when I started working there??
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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thomasxstewart
5 Comments
Causes Cancer NOT Cures Cancer.
Something that causes irratation & cell disintergration, epusulation & Goofed up DNA Growth.
Signed:PHYSICIAN THOMAS STEWART VON DRASHEK M.D.
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