September 16, 1999
The Nano Meter: Israel Adds to the Future of Technology
The key to this miracle of miniaturization is, of course, the microchip -- the integrated electronic circuit that, at 1-mm square, is so tiny it can be clutched in the jaws of an ant. But 20-30 years from now, scientists say, today's microchip will seem as cumbersome as the technology that powered the room-sized computer.
Today's aim is to shrink microchips to the size of human cells in an emerging discipline known as nanotechnology. This new technology, which measures matter in nanos or billionths of a meter, is already used in computers, mobile phones and photocopiers. As far as the dreamers are concerned, however, this is just the beginning of a future in which we manipulate atoms as easily as toy Legos.
There's still a long way to go. Yet Israel, with its repeatedly proven technological track record, is helping shorten the road. The first working electronic component for the nanocircuits of the future, for example, was created at the Technion-Israel Institute of Technology in Haifa. Called a nanowire, it's a string of tiny particles of silver, a thousand times thinner than a human hair, which actually passes a current.
"Wires are the foundation of any circuit, because they link circuit components to one another and to the outside world," says physicist Uri Sivan, who fathered the nanowire together with fellow physicist Erez Braun and chemist Yoav Eichen. The Technion team synthesized strands of DNA -- the molecule that makes up genes -- to make a scaffolding for the wire. Because DNA is an insulator that does not conduct electrical current, they attached grains of silver along the scaffold. The resulting nanowire is three times thinner than those created for microchips. Using molecules such as DNA to construct electronic devices is totally new, says Professor Jacob Sagiv, a materials scientist at the Weizmann Institute of Science in Rehovot.
"It's akin to the history of architecture. Early man lived in caves, carving the rock and extending his cave, until this technology reached its limits. Then he began chiseling out smaller stones for building blocks -- a technique that ultimately led to the skyscraper. This is what's happening today with electronic devices. Until now, we've built integrated electronic circuits by chemically carving crystals. Now that we're reaching the limits of this technology, we're learning to build structures and apparatus from the tiniest available building blocks: molecules and atoms."
With colleagues from Weizmann, Sagiv has built three-dimensional structures out of molecules, one of them shaped like a Star of David, with each of its sides only 1,000th the width of a human hair.
Just as the cavemen identified which stones built the best houses, so today's scientists are learning which molecules work best for them. Professor Reshef Tenne of the Weizmann Institute searched with colleagues in his department and at Oxford University in Britain for molecules to act as switches in computer memory. Unable to find this in nature, they shaped a single layer of nickel-chloride molecules into a sphere. This has not only produced highly reliable magnetic memory switches, it has also led to the creation of tiny molecular pipes.
The Weizmann nanotubes have been warmly welcomed by Professor Aaron Lewis, director of the Laser Center at the Hadassah Medical Organization in Jerusalem. He and Tenne believe the nanotubes will extend the use of his recently developed nanomicroscope, now in use from Beijing to Stanford.
"In this microscope, light is passed through a hole only nanometers in dimension, allowing us to examine single genes and even single proteins, and how they alter on the cell surface,'' Lewis says.
Punching glass to make a hole only 10 nanometers wide for the microscope itself demanded the creation of new technology. This knowledge led, in turn, to the development of tiny glass tubes into which Lewis slid an even tinier metal wire, creating an instrument that functions like a surgical laser with a wide range of different lasers depending on the electric pulses sent through it. A fraction of the cost of a variety of surgical lasers, it is now in clinical trials at Hadassah.
Another tool that evolved from the new technology is what Lewis calls a nano-fountain pen. It is, in fact, a hollow nanotube that can deposit chemicals on nanodimensions. Its uses may include chemically altering faulty genes.
Scientists are dreaming of a future in which cell-sized capsules will chemically recognize diseased cells and deliver appropriate drugs; in which measurements and instruments will be calibrated to an accuracy of one-ten thousandth of a millimeter; in which laboratory instruments will float on high-pressure air cushions to reduce vibration; in which we will build everything from computers to cheese sandwiches, atom by atom. And if the future is not yet now, it is certainly closer than ever before -- and with lots of help from Israeli scientists.
Wendy Elliman writes on business and technology from Israel.