Remaking the World One Atom at a
Time
Source: LA Times
Nanotechnology, manipulating materials on a molecular scale, holds
the promise of unlocking nature's secrets in everything from industrial
engineering to medicine.
In the not-so-distant future, bricks in new homes may repair
themselves when cracks appear. Cars may be coated with a diamond-strength layer
that will guard against scratches. Doctors might be able to diagnose hundreds of
illnesses by placing a droplet of blood in a machine and reading the results in
a few seconds.
All those scenarios, and many more, are conceivable through the
use of nanotechnology. Nanotechnology works in the world of the small--the very
small.
The goal of nanotechnology is to build things the way nature has
been doing it for millions of years: atom by atom, molecule by molecule, with a
"bottom up" approach.
"Nano" is a prefix used in the science world to mean "a billionth
of," and nanotechnology deals in billionths of meters, the dimensions at which
atoms mingle and molecules interact.
The idea is that if humans could tell atoms how to arrange
themselves and how to behave, many of the properties of a material could be
controlled at will. Just as nature turns the carbon atoms of coal into diamond
by changing their arrangement, so can properties such as color, strength and
brittleness be determined at the atomic level.
Scientists believe that if they could learn how to make a brick
atom by atom, its molecules could also be "instructed" to self-repair when a
crack appeared, or to react to humidity in the air by becoming less or more
porous.
Nanotechnology thus carries the promise of building anything
imaginable--from the tiniest cranes and motors to self-assembling layers of
plastic or metal.
Once the stuff of science fiction, these scenarios are becoming
plausible thanks to recent advances in the visualization of the world at the
nanoscale. New kinds of microscopes and powerful computer simulation programs
developed in the past 10 years have revolutionized nanotechnology.
The microscopes not only allow scientists to see atoms, but also
help them move atoms around, as in a famous 1990 experiment in which scientists
at IBM's Almaden Research Center spelled "IBM" with 35 atoms of the element
xenon.
And today, a team of IBM physicists announced an advance that
brings atomic-scale circuitry closer to reality. The development, dubbed
"quantum mirage," demonstrates that information can travel through solid
substances without the benefit of wires. See story, A1
The new tools are the "eyes, fingers and tweezers" of the
nanoscale world, Eugene Wong, assistant director of Engineering for the National
Science Foundation, told members of the House of Representatives at a hearing on
nanoscience.
The promise of nanotechnology is attracting increasing numbers of
enthusiasts in science, government and private industry.
"The reason why people are accepting this is because there's real
science behind it," said Tom Schneider, a mathematical biologist at the National
Cancer Institute. "We'll be able to build anything in the future."
Leading scientists who met last year at the National Science
Foundation said nanotechnology will have a major impact on the health, wealth
and security of the world's people and will be at least as significant as
antibiotics, the integrated circuit and man-made polymers were in the 20th
century.
In 1998 the White House Science and Technology Council created the
Interagency Working Group, a task force from science, industry and the
government charged with developing a vision for U.S. nanotechnology in the next
10 to 20 years.
The U.S. government invested $260 million in the technology in
1999. President Clinton has proposed a budget increase of $227 million for
nanotechnology research in 2001.
The Interagency Working Group predicts that nanotechnology will
lead to advances in such areas as information technology, medicine,
environmental science, the automotive industry, energy and national security.
Among the possibilities the group sees:
* In medicine, nanoparticles that will help ease drug delivery.
So-called smart devices made of drugs coated in layers of nanoparticles could
travel to sites in the body to cure localized cancers or lesions. Prosthetic
limbs and artificial organs may be coated with nanoparticles to prevent immune
reactions against the implants. Advances in diagnostics are also predicted, as
new machines based on protein and DNA detection allow small amounts of blood to
be screened for numerous diseases simultaneously.
* In electronics, production of faster and better computers of
Lilliputian dimensions. Already in production is a magnetic reader of nanoscale
size that reads information from a hard disk. Also in production are prototypes
of nano-sized memory chips with a thousand times the storage of current chips.
* In environmental science, nanomembranes that will filter
contaminants or remove pollutants, or will be able to detect and detoxify
contamination with chemical and biological agents.
Many challenges remain before scientists can unravel the secrets
of the nanoworld. According to a recent report by the Interagency Working Group,
the field today is "roughly where the science and technology behind transistors
was in the late 1940s and 1950s."
But with new visualization tools at hand, laboratories across the
country are taking leaps in understanding how atoms and molecules can be
arranged at will.
A number of laboratories are learning how to make molecules
self-assemble in particular patterns, such as pyramids or pillars. This is seen
as a crucial step in the quest to build novel materials atom by atom.
Scientists hope to soon make materials out of carbon "nanotubes,"
arrangements of carbon atoms lined together like pencils in a box. Such
materials would have one-sixth the density of steel, but 50 to 100 times its
strength.
"We know how to make them self-assemble [and] coat things," said
Richard Smalley, who works with nanotubes at Rice University. Carbon nanotubes,
many predict, may one day coat anything from cars to airplanes, imparting new
strength and durability to their surfaces.
Nature has been a master of nanotechnology for millions of years,
and scientists like Smalley believe much can be learned by looking at cells. All
the enzymes in our cells, he said, are nanomachines that have evolved to perform
unique tasks.
"They reached, in their little world, a level of perfection," he
said. "That's the dream of nanotechnology, to craft stuff at the ultimate level
of finesse. Nature, in the form of life, is the master of this game."
Nadrian Seeman's group at New York University is trying to use
another biological molecule, DNA, as the building block for three-dimensional
objects. His laboratory recently developed a nanorobotic device with two arms
made of DNA that can be rotated between fixed positions.
The researchers say the device is a first step toward developing
nanorobots that could one day build molecules in tiny nanofactories.
While initial applications of nanotechnology are likely to be
modest, there is talk of even more fantastic things. Some say that one day we
will be able make everything from scratch, by giving a computer a few elements
and instructing it to make anything from a car to an apple.
"It's not magic," Schneider said. "The idea is not magic."
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The Nanoworld
The prefix "nano" derives from the Greek word for dwarf. In the
world of nanotechnology, machines can be the size of tens or hundreds of atoms,
and properties such as color, strength and electrical conductivity can be
manipulated without changing a material's general composition.
Sources: "Nanotechnology: Shaping the World Atom, by Atom" by the
National Science Foundation
Copyright 2000 Los Angeles Times
by Sylvia Pagan Westphal
February 3, 2000