[akiselev]

The possibilities of graphene are vast and many and exciting but this is kind of scary. For all intents and purposes, graphene is nanotechnology and in certain forms can act like asbestos and has a lot of other unknown behaviors in the body [1]. Unfortunately the field of nanotoxicology hasn't really organized itself and caught up to the widespread use of nanocoating and other material science in industry[2]. I hope they find ways to make it extremely inert in the human body but there's much work to be done.

[1] http://www.nature.com/nnano/journal/v3/n7/full/nnano.2008.11... (CNTs are rolled up graphene and are formed in many graphene production methods as a byproduct)

[2] Nature has a whole series on this: http://www.nature.com/nnano/focus/nanotoxicology/index.html

[moocowduckquack]

Graphene flakes and carbon nanotubes are already relatively common in the environment as they are naturally occurring. You get carbon nanotubes in ordinary soot, for instance.

[adrianN]

Yes, and ordinary soot is not something you want to have regular contact with.

[Sharlin]

What about pencils? They're pretty much based on rubbing graphite on paper so that tiny graphene flakes break away and stick on the paper.

[moocowduckquack]

I thought it was lucky. Besides, it has been used in cosmetics for millennia.

[DanBC]

Breathing ordinary soot is sub-optimal.

[moocowduckquack]

The set of things that are sub optimal to breathe is pretty wide ranging though. I agree that breathing soot is not great, but I don't think this is particularly because it contains CNTs, as much as because it is a fine particulate that can get into and block up alveoli. I can't think of any fine particulates off the top of my head that are particularly good to breathe in.

[reyan]

Soot is the first known environmental carcinogen (https://en.wikipedia.org/wiki/Chimney_sweeps'_carcinoma).

[moocowduckquack]

I think Paracelsus description of lung cancer in miners might predate that.

"Paracelsus was a pioneer in chemistry and chemotherapy. He introduced mercury, lead, sulfur, iron, zinc, copper, arsenic, iodine, and potassium as internal remedies. But he gave due warning in his writings that all chemicals are potentially poisons, and concentration and dose are what make them poisonous or nonpoisonous. His collected papers on chemotherapy of various ailments, including cancers, were published by his followers in 1567 in a book,4De Grandibus. In it, there is the first description of industrial cancer, cancer of the lung in miners of metal ores and in the workers who smelted the ore."

from here - http://onlinelibrary.wiley.com/doi/10.1002/cncr.25825/full

[Dn_Ab]

To counterbalance, it is important to know that the structure of fullerenes strongly affects their chemical properties and hence toxicity. It does not immediately follow that just because CNTs are rolled up graphene that graphene will be just as toxic.

C60 for example not only shows no indication of toxicity but also appears to have health benefits. My general understanding is while relatively little is known about graphene, what is known suggests it is much safer than CNTs [1]. As well, CNTs are most dangerous when inhaled. CNTs can do damage once inside a cell but breaching membrane is a special enough cirscumstance to make it relatively easily solvable compared to how to mass produce the fullerenes in the first place. The asbestos like quality also seems to be length dependent [2] and most risky to workers - which is a more controllable environment. While it is important to know how harmful these substances may be to us and our environment and I am a tad wary of CNTs, one must keep in mind that the setting of these experiments tend to be exceptional. The fear mongering on this seems like it will end up like GMO, vaccines and fission; yet another inappropriately maligned technology of great potential.

[1] The results show that GO [digraphene oxide] has a moderate toxicity to organisms since it can induce minor (about 20%) cell growth inhibition and slight hatching delay of zebrafish embryos at a dosage of 50 mg/L, but did not result in significant increase of apoptosis in embryo, while MWNTs exhibit acute toxicity leading to a strong inhibition of cell proliferation and serious morphological defects in developing embryos even at relatively low concentration of 25 mg/L

[2] The apparent similarity between multi-walled carbon nanotubes (MWNTs) and asbestos fibers has generated serious concerns about their safety profile. The asbestos-like pathogenicity observed for long, pristine nanotubes (NTlong, see scheme) can be completely alleviated if their effective length is decreased as a result of chemical functionalization, such as with tri(ethylene glycol) (TEG).

http://link.springer.com/article/10.1007%2Fs11426-012-4620-z

http://onlinelibrary.wiley.com/doi/10.1002/anie.201207664/ab...

[weland]

It's ok, most of us, men, would stick our penises into anything.

[emil0r]

Speak for yourself.

[phpnode]

really?

http://www.landforce.co.uk/layout-images/home-wood-chipper.j...

[anon4]

really

http://nz.answers.yahoo.com/question/index?qid=2012032619114...