TR: Beyond shrinking microelectronics smaller and smaller, there’s been a lot of talk about using nanotechnology for other, mechanical, types of applications.
WHITESIDES: There are a lot of things that range from being potentially real to things that are science fiction. There’s the idea of very small autonomous machines that swim around in the bloodstream or something like that. I can see no way of realizing those. The reason is that, aside from the problems in building them, there are horrendous problems with power in anything that’s an autonomous system. There’ll have to be some truly deep invention before anyone figures out how to power small autonomous systems. We have examples of powered systems: for example, living cells, or organelles in the cell. But the cell is not actually a small object. Mammalian cells are about 25 micrometers across and even bacterial cells are 1 to 3 micrometers. Viruses, which are much smaller, are not powered. So power is one fundamental question. Friction in small moving systems is a second. Manufacturing is a third.
TR: Do you think some of these applications have been overhyped?
WHITESIDES: What Eric Drexler [K. Eric Drexler is a research fellow at the Institute for Molecular Manufacturing in Palo Alto, Calif.; his book Engines of Creation helped popularize nanotech] and others do is to construct a series of ideas based on making existing things smaller. They say if you have a big Rotorooter, why not have a tiny Rotorooter?
TR: But it’s clearly the case where just because they’re smaller…
WHITESIDES: They’re not necessarily better. Smaller is not necessarily always better.
TR: And they don’t always work as just a smaller copy.
WHITESIDES: Right. Not only are they not necessarily better, particularly if they’re more expensive, but also they may not work using the same principles. Which means that for really small structures, we’d probably have to invent new architectures and new ways of thinking about the problem, so that we can deal with the peculiarities of these small machines. And of course one of the interesting questions is, where is it going to be worth the effort to make machines that are really very small?
TR: If we had this conversation five or 10 years from now, any guesses what we’d be talking about?
WHITESIDES: I think we might be having a slightly different conversation. One that is less about how nanotechnology has changed the world and more about how inexpensive microtechnology has changed it. Right now, we reserve the world of microfabrication-making structures between several hundred nanometers and a couple of microns [a micron is a micrometer, one-millionth of a meter]- for electronic microprocessors and computer systems. It’s a very legitimate question to ask what happens when you extend many things that are now made at centimeter and millimeter scales to the micrometer scale, and what new functions do you get?