Scientists Pursue an Atomic Bricklayer
Nanotechnology conjures images that seem a little preposterous even to the most optimistic technophiles: microscopic cell-repair machines speeding through your bloodstream, tiny terabyte memory chips, dirt morphing into Caesar salad sound.
And even though nanotechnology--an approach to engineering where individual atoms are positioned to build practical structures--was first proposed by famed physicist Richard Feynman way back in 1959, practical applications remain scarce.
While chemical synthesis with water is commonly used to form new molecules and scientists have employed scanning-tunneling electron microscopes to probe and push atoms around, the self-replicating “nanobot” that would act like an atomic bricklayer remains the stuff of computer simulation.
But that doesn’t mean that the 325 enthusiasts who descended on a Palo Alto hotel for this month’s fifth Foresight Conference on Molecular Nanotechnology are dreaming of the impossible. Keynote speaker Richard Smalley, a Rice University professor who shared the 1996 Nobel Prize for the 1985 discovery of buckminsterfullerene, a previously unknown crystalline form of carbon, awed the audience with his method of chemically creating Bucky Tubes, conductive wire 100,000 times thinner than a human hair.
Smalley, founding director of Rice’s Center for Nanoscale Science and Technology, later spoke with The Times about the problems and potential of nanotechnology.
Q: What is molecular nanotechnology?
A: Nanotechnology is the art, science and technology of building stuff that does stuff on the nanometer scale. [A nanometer is one-billionth of a meter.] With the term “molecular” in it, there’s a special aspect to it: that the stuff you build has molecular integrity, which means when you put the last atom in it, it’s a molecule. It’s a molecule that maintains its identity in the real world with other molecules rubbing up against it.
The key is that it’s an object that does something. The dream here is to build machines, functional devices, things that go bump in the night, with molecular perfection.
Q: What kind of devices?
A: By far the most intriguing thing these days for me is to make electronic circuits with molecular perfection. It’s the ultimate level of shrinkage, from microelectronics to molecular electronics. You can’t get any smaller than that.
The talk I gave today had to do with how I think the wire should be made. But gee, it’s a long way from that to have a machine that’s on your desktop that puts together billions and billions of connections every minute without a single mistake.
Q: Can you give some examples of machines that would be useful at that scale?
A: Computers, communication devices, probes, sensors, tiny robots that you can communicate with that actually do things. If one could ever find a way to assemble these circuits with the sort of perfection we now take as commonplace when we put a Pentium chip together, but with molecular perfection, we’d have computers vastly faster and tremendously more powerful in terms of their memory. All the computers ever built would have all the knowledge of human civilization. And they’d be lighter than the little tape recorder you’re holding in my face.
Q: It sounds like a very science fiction idea.
A: In many ways, this is not a new idea: This is a bold frontier whose roots go back through chemistry and physics. For the past 200 years, we’ve been learning that matter is really made out of atoms. We’re doing the same thing now, except that we are dreaming bold dreams--to build molecular structures that don’t just have 10, 15 or 100 atoms in them but billions of atoms.
And not structures that nature has figured out ways to do all by herself. After all, every living cell in our bodies is chock-full of nanomachines of molecular perfection which we are having great fun in understanding. And now we’re beginning to play the game ourselves.
Q: How long until this really takes off?
A: There’s no sensible way of telling right now. It sometimes helps to visualize success, and to a great extent that’s what the community at this conference does. These people call for much bolder dreams to be in the brains of chemists--whose job in life it is to stick atoms together and make molecules--than traditionally those chemists would have.
Chemists have initially thought of this field as a lunatic fringe, but now, particularly the young chemists, the graduate students and some of the younger assistant professors are saying: “OK, I know these guys don’t know how to build these things, but my job is to build molecules. Can we build it?”
It seems that we are very far away from great examples. But it’s characteristic of this field that that will seem to be true until some morning you wake up and there it is in the newspaper.
Q: A lot of this research still takes place strictly using computer simulation. With molecular nanotechnology such a theoretical field, why is there so much dedication to its research?
A: In many ways, this community is a fan club. They’re obsessed with this idea and they want to do something. So they’re doing what they can. And, well, God love ‘em! (laughs)
Q: What’s keeping us from the Holy Grail of universal assemblers?
A: The two problems I often talk about are fat fingers and sticky fingers. If your dream is to have a little robot that picks up atoms and sticks them in particular patterns, you have to have fingers that are smaller than the bricks you’re putting in. And you have to be able to let go. Since the fingers have to be made out of atoms themselves, they’re not small enough and they’re sticky. I don’t know if this community fully appreciates the magnitude of that problem.
Q: How might this problem be solved?
A: When you’re building with atoms and you’re going to put a new atom in, it’s not just the new atom whose position is being affected, but also the atoms around it. Every atom has to move in just a particular way for the process to work right. Each one of those atoms has three directions it can move, and generally there’s 10 or 20 atoms in the near vicinity that are critically involved in a reaction. So the chemistry happens at 60 degrees of freedoms and you have to control every one of those 60.
We talk about “the chemistry between two individuals being right.” The notion is that it’s an extraordinarily complex interaction, even quite mystical. You don’t get a boy and girl to fall in love just by pushing them at each other. There are many dimensions involved.
Similarly, a finger at the end of the universal assembler’s robot hand cannot build with atoms by itself. There needs to be a catalyst or enzyme at the end of the finger, and then I think you can do it.
You could imagine the painting of the Mona Lisa as just information. You could instruct your 6-year-old daughter what paints to use and where to put them and she could paint the Mona Lisa: That ability to direct and manufacture on the nanometer scale in that way is very powerful. It’s just that there’s a subtlety at the end of this god’s finger--chemistry has to occur.
Q: So perhaps the “endless abundance” promise of molecular nanotechnology, where any amount of anything can be built by universal assemblers, is just an impossible dream?
A: A lot of that endless-abundance idea comes from the assumption that the universal assembler will fit into a cubic micron. Because then you can fill a coffee cup with billions of these things and you’ll have the mother’s milk of molecular nanotechnology.
You could put garbage inside a box, sprinkle some water in it, push a button that would radio instructions down to the universal assemblers, you’d wait a minute, and you open it up and there’s a cheeseburger.
That will only work if the assemblers themselves are micron-sized. But suppose the volume is a cubic centimeter. Than you can’t put billions in a coffee cup. And if each one of the assemblers that fit in the cup just works with one atom at a time, it’ll be years before something is made.
The medal for the Nobel Prize, on the back of it, has a graphic of the goddess of nature holding a cornucopia: And there’s a veil over her. And next to her is the goddess of science lifting off the veil. So it has long been a core concept of Western civilization that nature is intrinsically abundant and that science is the way to learn how to bring forth that abundance.
I think there is an end-to-need in that sense in the offing, but probably not through the universal assembler. Nanotechnology will happen, though. This business of building stuff that does stuff on a nanometer scale is the game. This is the ultimate level of finesse of manipulating atoms in our universe.
And a thousand years from now we will still be thinking of structures we don’t know how to build and ways to build them.
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David Pescovitz (pesco@well.com) is co-author of “Reality Check” (HardWired, 1996) and a contributing editor at Wired magazine. For more information on molecular nanotechnology, visit the Foresight Institute at https://www.foresight.org
