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."
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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