www.checkbiotech.org ; www.raupp.info ; www.czu.cz

Researchers at the University of Arizona are combining biology and
electronics to produce a new generation of microchips containing wires grown
with proteins from living cells, April 2006 by Max Jarman.

The work, funded by the National Science Foundation, could revolutionize
the way microchips are made, leading to smaller, faster and more efficient
circuits for cellphones, computers, MP3 players and other electronic
devices.

The technology also could be used to extract electricity from photosynthesis
cells in plants and test the effectiveness of anti-cancer drugs.

Professor Pierre Deymier, co-founder of the university's Nanotechnology
Interdisciplinary Research Team, is spearheading the research.

"There are tremendous possibilities," Deymier said.

The research focuses on proteins called microtubules, which form long, thin
hollow strands. In nature, they separate DNA and chromosomes to enable cells
to divide. They also form the tail-like flagella that allow cells to move.

"They grow and shrink, appear and disappear as they are needed," Deymier
said.

In the laboratory, researchers plan to use microtubules to connect
nano-sized components to standard microchip-sized circuits. That could
enable chips to be smaller and perform more functions. Chips also could be
produced for less cost with fewer layers of circuits.

"Our strategy is to look at what's happening in the cell, extract these
protein elements, modify them genetically so they can be attached to metal
surfaces, and then set up processes that exploit the biology for circuit
assembly," Deymier said.

Deymier's team has synthesized the protein and found a way to make it grow
strands of various lengths on any surface.

Another synthesized "capping" protein completes the process and forms an
attachment to another object.

The team has discovered a way to coat the inside of the hollow microtubule
strands with copper so they conduct electricity. By coating the inside of
the tubes instead of the outside, the exterior acts as natural insulation
and the strands remain the same size.

The protein strands are 25 nanometers in diameter but can grow to as long as
100 microns.

A nanometer is one billionth of a meter, and a micron is one millionth of a
meter.

Almost 5,000 of the protein wires would fit into a slot no wider than a
human hair.

"They are perfect for connecting nano-sized components to standard
microchip-sized circuit elements," Deymier said.

Although the researchers have not yet made an electrical connection using
the microtubules, Deymier said they are very close to doing so.

They also are working on other applications for the technology.

Microtubules are necessary for cell division, or mitosis, and researchers
are trying to create anti-cancer drugs that would attack the microtubules
and halt the growth of tumors.

Microtubule strands grown in laboratories could provide an efficient
platform on which to test anti-cancer drugs.

Another use could be to extract electricity from plant cells. Plants produce
a small electrical charge during photosynthesis, but it is difficult to
harvest the energy from the cells.

"Photovoltaic (solar) cells are not too efficient," Deymier said. "Plants
are much more efficient."

His team is working with researchers at the University of Tennessee who are
using plant proteins to convert sunlight to electricity. But they have been
unable to transfer the electrons to tiny circuits where they can be used.

"We believe microtubules could be used to bridge that gap," Deymier said.
"You have to look at biology as a toolbox and get biological systems to
engineering things."

[www.azcentral.com]

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