One of the first science-fiction movies I can remember seeing was Fantastic Voyage, in which a submarine and its crew are shrunk to microscopic size and injected into an injured man. Their mission: to vaporize a life-threatening blood clot in his brain. Among other things, the movie featured Racquel Welch in a wetsuit.
In a way, this science fictional vision came a step closer to reality this week when researchers at Cornell University announced they had successfully mated tiny metal propellers with organic molecules, creating ultramicroscopic machines–although they do not, alas, contain itsy-bitsy Racquel Welches.
The propellers don’t have any practical application, but they point they way to the day when microscopic devices could harvest medicinal molecules one by one from living cells, serve as “smart pharmacies,” detecting problems in cells the moment they arise and dispensing the needed pharmaceutical in response, or, yes, even sail through our blood streams, cleaning out clogged arteries and dissolving blood clots. Outside the body, similar devices could monitor environmental quality or clean up pollution.
Such devices are called “nanotechnology,” because the machines involved are only a few nanometres (billionths of a metre) in size.
The Cornell team, headed by bioengineering professor Carlo Montemagno, used electron gun evaporation, electron-beam lithography and isotropic etching (whatever that means) to create tiny propellers (750 nanometres long and150 nanometres wide, the size of a largish virus) out of nickel, coated with a special blend of chemicals.
They also manipulated an enzyme from genetically engineered Bacillus bacteria, making its chemistry match up with the propellers’. As a result, when the enzyme and the propellers were combined, they promptly assembled themselves into tiny motors.
Bacillus uses the enzyme to convert adenosine triphosphate (ATP) into energy. When Cornell’s tiny motors were mounted on 200-nanometre-high nickel pedestals and immersed in a solution containing ATP, some of the nanopropellers started twirling, for as long as 2 1/2 hours.
Of course, this is just a first step. The scientists are still debating exactly how the motors worked. (Actually, most didn’t: only five of the first 400 twirled at all. Some didn’t seat themselves properly on the pedestals; others flew off. Amazingly, those problems may have occurred because the propellers were too large: the researchers had to make them big enough to see under a microscope.) With further research, scientists hope to develop nanomotors that run on light rather than ATP, or use other enzymes.
Amazing as these tiny machines are, some scientists believe we may someday be able to create devices that operate on an even smaller scale. The Holy Grail of nanotechnology is something called an “assembler,” a computer-controlled device which would use a submicroscopic robotic arm to pick up atoms one at a time and pop them into place to build molecules–including more assemblers, making the assembler, like a living cell, self-replicating.
The concept of an assembler dates back to December, 1959, when Nobel-Prize-winning physicist Richard Feynman noted that as far as he could see, the laws of physics do not preclude humans manipulating individual atoms just as they manipulate large objects. The idea was developed further Dr. K. Eric Drexler when he was a student at MIT. His ideas were presented in a scientific journal in 1981 and in a book in 1986, and he taught the first university course in the subject at Stanford in 1988.
Cornell’s Montemagno believes being able to mate machines with living cells could allow us to turn cells, which are really tiny factories for making proteins, into factories that make the proteins we want; but the true, Drexler-inspired assembler would be capable of making literally anything, from diamonds to houses to airplanes, for next to nothing.
If such a device is ever invented, our notions of a market economy, driven by people making things that other people are willing to buy, would be obsolete: anyone could have anything. Nanotechnology could produce supercomputers the size of a human cell, could halt disease and aging, could produce food enough for everyone. Pollution would be eliminated, because toxic waste is just so much raw material to an assembler.
It could also be used as a terrible weapon…but then again, in a world of universal prosperity, maybe humans would find less to fight about.
Even if we never have such an assembler, the Cornell announcement this week proves that nanotechnology in some form is coming…and we can only guess at its impact.
As Montemagno puts it, “It’s almost like saying, ‘We discovered electricity — now what are we going to do with it?’”
