One More Thing You Shouldn't Inhale: The Past and Future (But No Present) of Carbon Nanotubes and Asbestos

This post was written by guest contributor Cyrus Mody.*

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There's a new study reported in Nature Nanotechnology entitled "Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study." Or, as the title seems to have been understood by reporters at the New York Times and elsewhere, "Blah NANO blah blah blah ASBESTOS blah PATHOGEN blah blah."

The gist of the original Nature Nano study is this: (1) we know asbestos fibers, once heralded as a godsend, can cause mesothelioma, a cancer of the lining of the lungs. (2) We know this has something to do with the high aspect ratio of asbestos fibers (they're long and skinny). (3) Carbon nanotubes can also have high aspect ratios, and people have sometimes worried that they might be "the next asbestos," so let's see if that's literally true at the cellular level. (4) Indeed, if we accept mice as a substitute for humans, and the lining of the body cavity as a substitute for the lining of the lungs, then cells react to the presence of carbon nanotubes somewhat similarly to the way they react to asbestos fibers. (5) That is, cells in the lining try to engulf the nanotubes, and succeed if the CNTs are short or tangled up into balls; but if the CNTs are very long (more than 13 microns or so), then the lining cells cannot engulf them and start releasing chemicals that cause cells around them to become inflamed. (6) With asbestos fibers, this kind of inflammation is a known precursor to cancer (though the exact mechanism is hazy); with the carbon nanotubes, the mice didn't stick around long enough to get cancer, but "these are research questions that must be addressed with some urgency before the commercial use of long CNTs becomes widespread" - i.e., look out for our next grant proposal!

Substantively, there isn't much surprising about this study. Indeed, the authors basically say "toxicologists have a paradigm for how mesothelial cells respond to long, skinny, tiny fibers - and that paradigm seems to hold true for carbon nanotubes." Their results aren't very conclusive, or even all that dire, yet the study has gotten plenty of attention. Why? Well, for one thing, the study was pretty savvily designed to fit into ongoing policy debates about nano. One of the authors, for instance, is Andrew Maynard of the Woodrow Wilson Center for International Scholars in DC.

Now, Maynard is a bona fide expert in this area, but his current day job is at a Washington think tank. His contribution to the article doesn't appear to have been technical, but rather he "provided intellectual input and contributed to the writing of the manuscript." I'm guessing that means he helped the authors figure out how to position their research in relation to previous studies on nanotubes, and used the considerable media profile of the Wilson Center's Project on Emerging Nanotechnologies to amplify their findings. It certainly looks like the Wilson Center primed science reporters to take a much keener interest in this study than they might normally.

I'd suggest a complementary reason why this study strikes such a chord. The Nature Nano article, and the research underlying it, reaffirms and plays to nano's deep, abiding antipathy toward the present. Whenever people talk about nano, whether pro or con, they seem to feel much more comfortable talking about the past or the future rather than the present. The nanotechnology enterprise has been built on rather grand promises of a "next industrial revolution" that will either devour the earth or make everyone immortal. Thus, any given piece of current research looks so wan in comparison to those promises that it's hard to actually label it as "nanotechnology." Nano research really only gets a lot of press if it's taken as a stepping stone to some brighter future - the "next transistor," for instance, rather than as a satisfying result of its own.

If nano only has a future with no coherent present, it certainly can't have a past. And, indeed, popular belief (even among practicing scientists) seems to be that the history of nanotechnology is nonexistent. Yet evocations of other pasts are all over public debates - nano will be just like the industrial revolution (only cleaner), just like biotechnology (only less controversial), just like the dot.com boom (only with a softer landing), etc. etc.

So note how the Nature Nano article plays with past and future to justify itself. It starts by pointing out that "the global market for CNTs is predicted to grow to between $1 and $2 billion by 2014." The NYT article summarizing the study starts thus: "nanotubes, one of the wonder materials of the new age of nanotechnology, may carry a health risk similar to that of asbestos, a wonder material of an earlier age that turned into a scourge after decades of use." An article in Science cited by the Nature Nano piece worries that an earlier study of the effect of nanotubes on fish could "put the field on the same path as previous abortive scientific revolutions such as agricultural biotechnology and nuclear power." The same article quotes Julia Moore, another Wilson Center PEN person, saying that "nanotech is in danger of becoming another Frankenfood controversy."

So the rationale for doing this study seems to be that: nano is promised to do great things in the future; asbestos was promised to do great things in the future in the past; asbestos ultimately became publicly controversial and cost a lot of people a lot of money and/or their lives; nano is doomed to follow the same trajectory in the future as fields that it looks like in the past; nanotubes look a bit like asbestos, which caused cancer in the past, so we should see if nanotubes will cause cancer in the future.

This isn't meant to belittle the findings of this study - I think it's great that this kind of research is being done. I am a little amused, though, by nanoists constant preoccupation with the past and the future. My normative suggestion would be that nanoists should be more focused on the present, beginning with studies like this one. What does this research actually tell us about mesothelial cells that we didn't know before? What does it tell us about how nanotubes interact with those cells - not just "CNTs could cause cancer," but what are the actual mechanisms by which cells and CNTs encounter each other? How could we design CNTs to tell us more about mesothelial cells in experimental conditions? How could we design CNTs to interact less harmfully with mesothelial cells in real world conditions? It's those kinds of questions, which connect the dots from past to present to future, that seem to be missing in nano discourse. Instead, we see to many vague evocations of various pasts and vague assertions of various futures, with no clear bridge between them.

*Cyrus Mody is an Assistant Professor of History at Rice University. His book, Instrumental Community: Probe Microscopy and the Path to Nanotechnology (to be published by MIT Press) explores the co-evolution of an experimental technology (the scanning tunneling microscope and atomic force microscope and their variants) and the community of researchers who built, bought, used, sold, theorized, or borrowed these instruments. You can also read more about his studies of nanotechnology as an STS scholar in last year's discussion here at The World's Fair.

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I think "CMTs could cause cancer" is vitally important information to establish. Because after nano leaves the lab, it goes into the hands of the MBAs and moneymen. Without rock-solid science (and sometimes even with it), the MBAs and moneymen will feign surprise and cry fake tears when, predictably, their workers come down with this dread cancer, because - if history is any guide - these same MBAs and moneymen won't think it is "financially prudent" to invest in safety gear and procedures without rock-solid science on causation.

By Woody Tanaka (not verified) on 03 Jun 2008 #permalink

I'd suggest a complementary reason why this study strikes such a chord...Whenever people talk about nano, whether pro or con, they seem to feel much more comfortable talking about the past or the future rather than the present.

Perhaps, people are looking very clearly at the present. They are seeing the results of a century of wide-open chemical science that had unexpected (or even expected but denied) consequences: PCBs, Bisphenol A, DDT, Agent Orange, CFCs, petrochemical fertilizers (that's just a quick list off the top of my head). All of these had benefits but also created health/environmental problems.

When it comes to nano, perhaps a much needed caution is being exhibited. Too borrow a bad cliche, with great power comes great responsibility.

Thanks for these illuminating remarks on why the paper got so much publicity! In my opinion as a mesothelioma scientist it's a ridiculously hyped finding without any real substance.

The link between inflammation and asbestos is still hypothetical, and there are countless substances that induce inflammation of the mesothelium without leading to cancer.

Sorry, I meant to say the link between inflammation and mesothelioma!