Nanotechnology: Blobs, Shapes & Chunks must be treated differently

Ralph Hermansson writes about nanotechnology safety in today’s San Francisco Chronicle. He had interviewed me for the piece:

Bacteria-proof forks and knives. Pants that never get stains. Computer chips with a considerably better memory, making conventional chips seem almost senile. Sports equipment made of materials that are much harder yet more lightweight than today.

Science fiction? Not at all, these products are readily available — thanks to nanotechnology…

Silver nano particles are of special concern. These germ-killing particles are used in shoe liners, food-storage containers and washing machines, among other things. Since there is a risk that the particles escape into the aquatic environment, beneficial bacteria and other organisms may be killed. For this reason, the U.S. Environmental Protection Agency is demanding evidence that these kinds of products are not harmful to the environment.

Other areas of concern are transparent sunscreens that block all ultraviolet rays just as efficiently as any zinc paste. When you apply this type of sunscreen to avoid skin cancer, small nanoscale particles can enter your system through the skin. The effects this might have in the long run are hard to predict.

Christine Peterson, vice president of the Palo Alto think tank Foresight Nanotech Institute, also stresses the need for more research.

“There are so many different nano particles that it’s misleading to put them under one name,” she said.

“All they have in common is the size. It’s kind of like comparing butter, basketballs and a boulder — you just can’t. Some particles probably will have issues and some won’t be dangerous.”

Butter, basketballs, and boulders are macro examples of nanotech blobs, shapes, and chunks: all “nanoparticles”. The blobs are oily and meant to dissolve, the shapes have properties that depend on their 3D configuration (bucky balls, nanotubes, nanohorns), and the chunks are just smaller irregular pieces of materials we’ve used as nanopowders before. These three categories are different and need to be distinguished if we are to regulate safety in a sensible way. And that’s just a beginning: nanoparticles can act very differently depending on their specific size, surface chemistry, shape, and any coatings that accumulate on them.

Of course later, in addition to the butter, basketballs, and boulders, we’ll have nanoscale active devices and systems of devices that perform operations such as manufacturing — again, very different and needing to be regulated separately.

The piece also looks at the upsides, such as cancer treatments:

“The research results so far have been totally promising,” Peterson said.

OK, maybe not “totally”, but highly promising for sure! —Christine

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