Toxicity of carbon nanotubes?

[Gullible Jones]

Wikipedia has nothing on it, but some googling got me this.

As one might expect, it appears that single-walled nanotubes - short ones, anyway - are very toxic. Not surprising, considering the toxicity observed in buckminsterfullerene, and that nanotubes are basically very small fibers...

I don't think this will be a huge problem when it comes to making nanotube-reinforced materials, but I'd like to know what happens to those ideas for using nanotubes in the medical field. Might it not be such a good idea to use these things in peoples' bodies?

[doltish]

I thought inhaling fibers was dangerous because they interfered with lung functions. Thats why having asbestos in your home isn't really dangerous unless the material it is in starts to tear or disintegrate - cause inhaling it is the problem.

I dunno I could be wrong.

[TheBlackCat]

I don't think this will be a huge problem when it comes to making nanotube-reinforced materials, but I'd like to know what happens to those ideas for using nanotubes in the medical field. Might it not be such a good idea to use these things in peoples' bodies?

That all depends on how they are used. Every material technically recieves a negative reaction from the body. Biomedical engineers have gotten quite adept at isolating potentially harmful materials so they do not contact living tissue. I doubt carbon nanotubes would be of much use on their own. They would mostly likely be used in a composite of some sort, most likely a carbon-carbon or polymer-matrix composite (although metal-matrix composites may also be possible). This would go a long way to preventing the nanotubes from coming in contact with living tissue. Certainly, you wouldn't want to use them in tubes (which can break through fatigue), high-wear applications (like the polymer socket that the ball from an artifical hip fits in), or nails or screws (which relatively routinely). On the other hand, they could be useful for in-bone implants like total hip or total knee replacement (as long as they are not rubbing against anything), scaffolding for holding broken bones together, the springs for artificial hears (since these never come in contact with any tissue or body fluid), the shells for various free-floating devices like batteries or insulin pump, or really anything that has a low chance of breaking or cracking. Remember, they stick lithium-ion batteries in people all the time. Artifical hearts are full of components that can induce clotting. MAny materials could induce clotting if exposed to blood. There are lots of potentially dangerous materials used in the human body. It is all a matter reliably keeping the material from reaching a tissue where it might do damage.

[Gullible Jones]

True... I was thinking more along the lines of an idea for carbon nanotube electrodes designed for implantation in the brain. The idea was that nanotubes would be more biocompatible than, say, silicon, and cause less scarring... But it sounds to me like using nanotubes for such electrod arrays would result in a lot of damage to the brain.

[Ken G]

TheBlackCat has obviously thought about this a lot. I see a nanobioengineer in the making here, seriously. (How's that for a new job description?)

[TheBlackCat]

I'm a bit ahead of you here. I am already a biomedical engineer. I know all of that stuff because I took a course on biomaterials, where we covered the subject in depth. My focus is on the brain and nervous system, but we still stick lots of stuff in the brain so biocompatibility is a big deal (as gullible jones has already said). I'll leave the nanobiotechnology (which is a very popular field) to my classmates.

Silicon is pretty darn biocompatible, even ignoring the biocompatibility issues I don't see nanotubes really replacing them owing to their massive cost and the ease with which silicon chips of just about any sort of manufactured nowadays.

[Ken G]

Ah, and they said battleships were better than aircraft carriers too... (just kidding, I salute your hesitence to "jump on the bandwagon", I just hope that whatever you choose you will be in a position to use your ability to think outside the box. or rather, to see the larger box.)

[TheBlackCat]

Ah, and they said battleships were better than aircraft carriers too...

Yes, but we are more talking about choosing between a battleship that can be mass-produced by existing techniques and another that has a few more guns but costs several thousand times more and is almost impossible to make

[captain swoop]

Well, if it's the US defence procurement they will go for the expensive one.

[publiusr]

They already are--Enterprise is to be axed and replaced with another supercarrier.

But we don't have money for NASA and biomedical research...

[sarongsong]

Carbon was recently fingered as the chief culprit responsible for the ocean's ~100 dead zones, by a researcher at Scripps Institute of Oceanography, on TV last week.

[SolusLupus]

out of curiosity, might we ever get to the point of being able to mass-produce Carbon Nanotubes?

[TheBlackCat]

Carbon was recently fingered as the chief culprit responsible for the ocean's ~100 dead zones, by a researcher at Scripps Institute of Oceanography, on TV last week.

I would like to see a link to that. There are many different forms of carbon, which one was the supposed culprit could be interesting. I can pretty much guarantee it wasn't carbon nanotubes, however

[sarongsong]

I would like to see a link to that. There are many different forms of carbon, which one was the supposed culprit could be interesting. I can pretty much guarantee it wasn't carbon nanotubes, however

No, it's the result of human impact, tho, it's:
"...sugar in the water---the sorts of things that come out in sewage...scientists [have been accustomed to] measure for things like phosphorus and nitrogen...never for carbon...carbon is the thing that kills coral..." ---Dr. Nancy Knowlton, Director of SCMBC
The (realplayer) video of the above excerpt is from:
Perspectives on Ocean Science: Scripps Center for Marine Biodiversity and Conservation
(59 min. | #9909 | 8/10/2005)
She first mentions dead zones at 18:30 into the lecture; carbon at 34:00

[01101001]

out of curiosity, might we ever get to the point of being able to mass-produce Carbon Nanotubes?

Nature: Nanotube sheets come of age

Large, transparent sheets of carbon nanotubes can now be produced at lightning speed. The new technique should allow the nanotubes to be used in commercial devices from heated car windows to flexible television screens.

"Rarely is a processing advance so elegantly simple that rapid commercialization seems possible," says Ray Baughman, a chemist from the University of Texas at Dallas, whose team unveils the ribbon in this week's Science.

Nanotech-now.com: Carbon nanotubes of the highest purity

High-quality carbon nanotubes (CNT) can now be manufactured on an industrial scale at considerably lower cost than ever before. Bayer MaterialScience AG plans to market the nano-sized materials worldwide under the trade name Baytubes.

Carbon Solutions Inc.

Carbon Solutions offers specialty chemical manufacturing in all aspects of carbon science - please contact us for any needs that you have in carbon materials, particularly carbon nanotubes.

[01101001]

[...] carbon is the thing that kills coral..." ---Dr. Nancy Knowlton, Director of SCMBC
The (realplayer) video of the above excerpt is from:
Perspectives on Ocean Science: Scripps Center for Marine Biodiversity and Conservation
(59 min. | #9909 | 8/10/2005)
She first mentions dead zones at 18:30 into the lecture; carbon at 34:00

Rohwer Lab: Coral Reef Microbiology and Decline

In collaboration with Dr. Nancy Knowlton [...] Our data shows that of the many commonly cited stressors of corals, organic carbon (OC) loading is the most problematic. Coral death induced by OC can be delayed with antibiotics. Additionally, OC loading causes the coral-associated microbial communities to grow much faster then normal. This strongly suggests that changes in the bacterial community, and not the stresses themselves, are responsible for coral mortality.

That's organic carbon.

Maine PEARL: Dissolved Organic Carbon

DOC is organic material from plants and animals broken down into such a small size that it is “dissolved” into water. Some DOC molecules have a recognizable chemical structure that can easily be defined (such as fats, carbohydrates, and proteins) however most have no readily identifiable structure and are lumped under the term humic or tannin substances.

[sarongsong]

out of curiosity, might we ever get to the point of being able to mass-produce Carbon Nanotubes?

"...Research on nanotubes is still in the very early stages. However, the material could have applications in construction and electronics, as well as more mundane uses in items such as plastic utensils, rubber gloves, furniture, electronic games and toys..."
http://starbulletin.com/2005/11/25/news/story06.html

[publiusr]

I'm glad my old friend Ug the caveman didn't invent fire today, or he's get sued.

"Next week:
The Wheel--Boon to Mankind or Technology run Amok?"

[gopher65]

I'm glad my old friend Ug the caveman didn't invent fire today, or he's get sued.

"Next week:
The Wheel--Boon to Mankind or Technology run Amok?"

Didn't you ever read the Homecoming series by Orson Scott Card?. In that series there was a supercomputer running humanity (on another planet). One of the ways it controlled humanity was by preventing the development of the wheel.

[westwolf_ca]

Hello, just come to visit.