[tt] 60 micron-wide robots to explore the brain

[Hughes, James J.]

http://www.postbulletin.com/newsmanager/templates/localnews_story.asp?z=
20&a=352755

Microscopic robots could explore brain

7/19/2008 9:47:17 AM

By Zoe Elizabeth Buck

McClatchy Newspapers 

RALEIGH, N.C. -- Gas prices have auto manufacturers rushing to make cars
smaller, but Bruce Donald drives vehicles so tiny you need a microscope
just to see one.

Donald and his team of Duke University computer scientists have
constructed a fleet of fully steerable microrobots small enough to move
around on the head of a pin. Robots this small could someday explore
brain tissue or manipulate delicate electronics.

The robots are about 250 microns long and 60 microns across. They are
thinner than the width of a human hair, and you could line two of them
end to end inside the period at the end of this sentence.

They look like spatulas that move around on a charged surface using
small, springlike steps similar to an inchworm's crawl. The microrobots
have a long, thin arm that can be lowered and used as a pivot for
turning, allowing the machines to steer freely in any direction.

Tasks on a tiny scale

The microrobots will soon be put to work probing the architecture of
animal brain cells. Donald is working with Duke neurobiologist Richard
Mooney and physicist Gleb Finkelstein to put the little robots to work
as drill rigs, driving electrodes mounted on the front of the robots
into the cells. Eventually Donald hopes this technology can help
neurobiologists understand how the human brain works.

"Just like when the car first appeared and people saw all sorts of uses
for them, there are all kinds of applications for something that can
move around and do tasks at a microscopic scale," Donald said. "These
microrobots will be able to act as bulldozers, pick-up trucks and
construction machinery. They can drive around by themselves, and now we
can control large groups of them."

Donald and his collaborators drive the microrobots in much the same way
that young children drive the remote-controlled toy cars they use to
terrorize parents and siblings.

"We send the same signal with instructions to the whole group of
microrobots," he said. "Even though every robot gets the same message,
we constructed multiple types of robots, which we call species. Each
species has a slightly different physics, so they will all react to the
instructions differently to carry out the task most efficiently."

Ronald Fearing runs a microrobotics lab at the University of California
at Berkeley.

"I think of what professor Donald is doing as shrinking a factory to the
size of a computer chip," Fearing said. "The microrobots are like little
workers and machinery that can build things and fix things in the
factory. This is really neat when you're talking about components that
can't be handled by hand."

Lots of potential uses

With so many potential applications, the future of the robots is
unclear.

"The size is obviously a significant achievement," said Dan Popa,
assistant professor of electrical engineering at the Automation and
Robotics Research Institute at the University of Texas at Arlington.
"But right now what Donald has is mostly a curiosity. The next question
is what these robots will be used for, and what that is is not entirely
clear."

Popa said he could see Donald's microrobots being used to manipulate
microscopic materials, a field called nano-manufacturing.

Although the microrobots are only following instructions right now, they
are likely to start getting more intelligent in the future.

"My students are working on installing circuits that would allow the
robots to do simple computations on their own," Donald said.

But there's no need to fear hordes of Donald's microrobots taking over
the world just yet.

"They're carefully engineered so that they can't escape from the
surface," he assured, "so there's nothing to worry about."