What do we know about nanomaterials?

Via a press release from Consumers Union, the July 2007 issue of Consumer Reports will include a call for more testing and regulation of nanotechnology:

[T]he risks of nanotechnology have been largely unexplored, and government and industry monitoring has been minimal. Moreover, consumers have been left in the dark, since manufacturers are not required to disclose the presence of nanomaterials in their labeling.

Your first question may be, what the heck is nanotechnology? From the press release,

Nanotechnology involves creating new materials or reducing the particles in standard materials to sizes as small as a nanometer, or about 100,000 times smaller than the width of a human hair. At this size, the characteristics of materials change, carbon becomes 100 times stronger than steel, aluminum turns highly explosive, and gold melts at room temperature, for example. New characteristics such as these can be used to bring positive changes to consumer products. But in some cases, they may make benign materials toxic and toxic ones more hazardous.

Needless to say, the effect of size on the properties of materials is a hugely fascinating area for physical scientists and engineers. It opens up all kinds of possibilities -- for energy efficiency, drug delivery, and so forth -- that might not have been dreamed of on the basis of our understanding of macro-properties of various materials. There is a great deal for scientists to learn here.

Of course, that means there's a great deal that scientists don't yet know about nanoparticles.

It's worth noting that manufactured nanoparticles aren't the only nanoparticles around. There are nature-generated nanoparticles (like the salt particles in sea air, nano-bits of ash spewed by volcanoes). As well, there are nanoparticles generated as side-effects of human activities (like burning diesel fuel or welding). There is some research about how such nanoparticles behave (especially when interacting with human bodies) but much is still unknown.

When nanoparticles are engineered to be put into products, it seems to me there's a good argument for the responsibility of the folks engineering them and distributing the products to seek good information about potential risks of these nanoparticles. Indeed, I made that argument earlier this year in a blogospheric conversation about nanotech:

Unless nanoparticles and nanodevices are going to stay in the scientists' well-controlled sandbox, scientists have an ethical obligation to ask the questions about what they could do when made a part of the wider world. Non-scientists, after all, have no way to get this information on their own short of becoming unwitting guinea pigs. And, scientists have an ethical obligation to communicate that information, clearly and honestly, to the people who could be effected, enabling those people to make the best decisions they can about whether to embrace nanotechnology or to opt out. A truly free market, after all, affords the consumer the option not to buy.

But nanoparticles aren't just a concern for people deciding whether to buy them in sunscreen or paint (a decision made more difficult by the fact that the label on the product need not identify whether the product contains nanoparticles). Nanoparticles in diesel exhaust may well impact the health of people just trying to breathe rather than to exercise their choices as consumers. The scientists involved in researching the effects of the engineered nanoparticles seem like they could also contribute quite a lot to our understanding of the effects of the "casual" nanoparticles produced by other human activities.

And here's where the recommendations from Consumers Union come in. From the press release again:

Although no confirmed cases of harm to humans from manufactured nanoparticles have been reported, there is cause for concern based on several worrisome findings from the limited laboratory and animal research so far. For example:

  • Certain benign materials can become toxic when nanosized because microscopic particles tend to react more readily with human tissues and other substances.
  • Nanoparticles can enter the body and its vital organs, including the brain, much more easily than can larger particles. And some are now used in food additives, cosmetics, and other products that are ingested or applied directly to the skin.
  • Some nanomaterials seem to linger in the environment -- especially in the water supply, where studies suggest they can damage the ecosystem.
  • Fullerenes, composed of spherically arranged carbon atoms used in cosmetics and other products, might damage cells in fish, and harm human liver cells and DNA.
  • Carbon nanotubes have similar fibrous shapes to asbestos and some animal studies have indicated that one type can inflame the lungs.

Consumers Union, the nonprofit publisher of Consumer Reports, believes that the responsibility for protecting consumers rests mainly with government and industry. In particular, CU calls for the government to provide more funds for risk research and regulation. It also calls for the FDA to assess safety information on nanoingredients in cosmetics, food additives, and other products before they're sold and to require manufacturers to report health problems linked with those ingredients.

There's nothing scientists love more than regulation, I know! But the little guy (here, the nonscientist who may be encountering nanoparticles in her purchases or her environment) can't get the necessary safety information on her own. The scientists working in nanotechnology are the ones who have the means to get the information we need, and this ability seems to give them the duty to seek this knowledge and to share it with the people who need it.

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For what it's worth, I'm a postdoc funded on an NSF grant to look at nanoparticle toxicity to aquatic organisms. I can tell you that this is THE hot issue in ecotoxicology circles, and is where the money is going. Right now, anything with "nano" in it has a good chance of being funded or published.

By Johnny Chimpo (not verified) on 04 Jun 2007 #permalink

WARNING! This product may contain MOLECULES!

Isn't that what most "nanoparticles" are? It doesn't take that many carbon molecules to reach a nanometer, and one of the big semantic debates in cosmochemistry right now is whether or not nanodiamonds should be thought of as crystals or molecules- their diffraction spectra is dominated by their lattice, but their chemical behavior is controlled by the surface bonds. And a 50-unit-cell diamond is way smaller than even a modestly sized protein.

I'm assuming that "nanoparticle" is a term of art that at least the nanotech researchers can disambiguate from your run-of-the-mill molecule. Maybe that's a bad assumption and "nanoparticle" is what the cool kids are calling molecules these days in order to secure grants.

WARNING! This product may contain MOLECULES!

For some reason, this reminded me of the signs in my graduate lab that said "NO SOLVENTS DOWN THE DRAIN!" This always made me laugh, what with water being a solvent of some renown (and the one I used for the reactions I studied).

I always figured Consumer's Union was too busy seeing how many ping pong balls they could fit into the trunk of a 2007 Taurus to worry their pretty little heads off over something like this.

Yeah, there are plenty of "natural" nanoparticles, but the ones we're concerned with are manufactured: C60 buckyballs, carbon nanotubes, and, in our lab, nanometals. A lot of their properties are different on the nano scale than on the bulk scale, and we're actually getting ahead of the curve on this one, trying to figure out the potential environmental effects before there has been a release.

By Johnny Chimpo (not verified) on 05 Jun 2007 #permalink

Maybe that's a bad assumption and "nanoparticle" is what the cool kids are calling molecules these days in order to secure grants.

In some ways the prefix "nano" is overused in this manner. Nanotechnology can generically consist of researching or controlling material on the nanometer scale.

But while nanosurfaces, nanoelectronics and nanomechanics feels like safe nanotechnologies, old and new nanoparticles are a bit of biological question mark. It seems we haven't evolved to keep them out of our bodies or cells. IMO lingering and biologically active nanoparticles feels too much like earlier persistent chlorocarbons...

Incidentally, I think that the catalytic titanium surfaces that are now being used to break down harmful particles are nanoscale thickness for practical and economical reasons.

By Torbjörn Lars… (not verified) on 05 Jun 2007 #permalink

Hi professor! I think that you're pretty knowledgeable about nanotech, so I'd like to ask for a brief explanation on the specific connection between nanotech and ion implantation. Also, the connection between nanotech and semiconductors. Thanks!