|
Frontiers
Small Miracles Happen at Nanotechnology Hubs
February 1996
|
At home on a nanofabricated imitation of a leaf, a fungal cell uses the silicon ridges as directional signals as it grows toward the bull's-eye's center.
Credit: H.Hoch |
Rust fungi are named for the reddish dots the
spores make on leaves, but the fungi don't damage plants from the outside.
Just as a cold virus attacks people internally, rust fungi enter bean
plants through their leaves' stomata (or pores) and decimate the plants'
inner cells.
But until plant pathologists looked much closer and used the Cornell Nanofabrication
Facility, little was known about how the fungal cells grew into the stomata.
Cornell researcher Harvey Hoch and his colleagues used silicon to mimic the microscopic
bumps and dips found on bean leaves. They discovered that the fungi grow according
to the plant's own topography. In fact, the stomata's guard cells--features
no more than 500 nanometers in height or about 100 times smaller than the width
of a human hair-signal the location of the stomata to the fungal cells, telling
them where to enter the plant.
It's a tiny discovery made possible by tiny technology, but by nano standards,
the 500 nanometer guard cells are big. In the fast developing world of nanotechnology,
researchers are measuring results in terms of one nanometer (10-9 meters). With
machinery that small, scientists can even play with atoms.
"We can go down and move an atom," confirms NSF's Marvin White, Program Director
of the National Nanofabrication Users Network (NNUN). "You take a very, very
tiny needle and use it like magnet," adds Debbie Crawford, White's colleague.
While the work sounds like a science fiction story, the process may be useful
in creating minuscule transistors.
Other projects include creating nanosensors to find defects in the surface of
silicon chips and building medical probes so small that they won't damage the
tissue.
"The breadth of possibilities is immense," says White, "but we need to allow
more people to build and use these nano-structures."
For the last year, NSF has been increasing nano-access through NNUN, a ten year
project co-sponsored by the Engineering, Biological Sciences, and Mathematical
and Physical Sciences Directorates.
So far about 1,000 researchers, many from small businesses, have accessed the
Nanonet's Web site and looked at the research going on in NSF-sponsored nanotechnology
hubs-Stanford, Cornell, Pennsylvania State, Howard, and The University of California
at Santa Barbara.
On the Web site, investigators can ask questions, do research or fill out order
forms for future nano projects.
If the project is accepted the scientists either go to the nano-technology hub
themselves, or continue to work remotely. The NNUN was deliberately designed
so that remote users would have first access to the equipment, says Crawford. "We
want this system to enable people from all over the U.S. to use nanoscience."
|
