Designer - Silicon chips have made everything electronic smaller,
faster, and cheaper. Now scientists are working to make circuits so small,
we wonâ€™t see them at all. (1/16/03)
Detector - Nearly a year after the anthrax mail attacks we still have
a long way to go for that perfect detector. (8/30/02)
Elsewhere on the web
Initiative/National Science Foundation
Nanotechnology Initiative: Leading to the Next Industrial Revolution
- program to help school children learn about nanotechnology
Next time youâ€™re struggling with computer cables, consider this: according
to a report in the journal Nano
Letters, scientists are working on a way to connect a computer to living
Why? As this ScienCentral News video reports, the effort could help protect
us from bioterror.
Fighting hazards from a computer
If we are attacked with nerve gas or anthrax, weâ€™ll need to know whatâ€™s
coming our way as quickly as possible. Nanotechnologists are working on new
sensors that are both small and sensitive enough to work anywhere that we are
threatened with biological or chemical weapons.
At Purdue University, chemist Jillian
Buriak has come up with a detection lab on a chip. She uses extremely tiny
pieces of gold that can connect from a computer to natural sensors found in
living cells to pick up traces of biochemical agents.
To make the sensor on a chip, Buriak starts with "nanoparticles"
of gold. A nanoparticle is only a few atoms wide, many thousands of
times smaller than the width of a human hair (80,000 nanometers wide). Gold
was her first choice, because it doesnâ€™t rust, giving a chip a pristine
surface. Gold also conducts electricity very well.
In Buriakâ€™s lab, her team dips metal chips into a solution of gold nanoparticles.
Over time, gold fragments form a bumpy coating on a chip. The longer a chip
spends in solution, the rougher its surface becomes. This surface is key to
Buriakâ€™s next step: attaching to the chip organic molecules—the
building blocks of living cells—that react in the presence of chemical
or biological agents.
The new bumpy coating means that the chipâ€™s surface has grown considerably
larger. Buriakâ€™s graduate student and co-author, Lon A. Porter, Jr., compares
the chipâ€™s altered surface to our brains: "Your brain packs a lot
of surface area into the limited space inside your skull by folding in on itself
The chipâ€™s rough surfaces offer plenty of nooks and crannies where molecules
can cling securely. The gold also lets electric signals flow freely to and from
From a computer loaded with Buriakâ€™s new chip, the molecules can be told
to sniff chemical or biological toxins out in the open, just as they do inside
living cells. If a molecule detects something dangerous, it reacts chemically,
triggering a small electrical change. That sends an electronic signal through
the gold nanoparticles. The moleculeâ€™s signal then shows up on the computerâ€™s
Buriak predicts that "nanoparticles could be the bridge we need to help
computers interact with the biological world." Because she and her researchers
also have come up with ways to deposit gold nanoparticles on a chip in specific
patterns, they believe that their techniques have commercial use. They could
result in more efficient semi-conductors—and therefore computers that
can work faster
on less power. They also would cost less: Buriakâ€™s technique requires
a very inexpensive form of gold that in the form of her solution, is worth only