[ExI] 'Boosting' research to develop world's fastest nanomotor

[John Grigg]

http://www.biodesign.asu.edu/news/boosting-research-to-develop-worlds-fastest-nanomotor

In a "major step" toward a practical energy source for powering
tomorrow's nanomachines, researchers at Arizona State University's
Biodesign Institute report the development of a new generation of tiny
nanomotors that are up to 10 times more powerful than existing motors.

Just like weekend hot-rodders who tinker with their car engines in the
ultimate quest for speed, a research team led by Joseph Wang, who
directs the institute's Center for Biosensors and Bioelectronics, set
out to improve on the design of current nanomotors. These so-called
"catalytic nanomotors" are made with gold and platinum nanowires and
use hydrogen peroxide (the same chemical that bleaches hair) as a fuel
for self-propulsion.

But these motors are too slow and inefficient for practical use, with
top speeds of about 10 micrometers per second, the researchers say.
One micrometer is about 1/25,000 of an inch or almost 100 times
smaller than the width of a human hair. (If one could somehow magnify
the nanoworld to human scale by multiplying by a factor of 100,000,
the speed would be the seem the same as a walking speed of 3.6 miles
per hour.)

Wang and colleagues supercharged their nanomotors by inserting carbon
nanotubes into the platinum, thus boosting average speed to 60
micrometers per second. This was the first time that carbon nanotubes
had been added to the existing gold and platinum nanowires. The tiny
tubes, only a few atoms thick, help conduct electricity and heat.

This is the first example of a powerful, man-made nanomotor, said
Wang, who is an ASU professor with a joint appointment in the
departments of Chemical and Material Engineering in the Ira A. Fulton
School of Engineering and Chemistry and Biochemistry in the College of
Liberal Arts and Science.

Spiking the hydrogen peroxide fuel with hydrazine (a type of rocket
fuel) kicked up the speed still further, to 94- 200 micrometers per
second (using the same multiplying factor of 100,000, the top speed
would now be equal to a moped-like speed of 43.2 miles per hour). This
innovation "offers great promise for self-powered nanoscale transport
and delivery systems," Wang states.

The Biodesign team is interested in more than just bragging rights at
the nanotechnology research racetrack. By packaging the nanomotors
with the right cargo, Wang says the powerful nanomotors could one day
deliver disease-fighting drugs inside the body to invading pathogens
or tumor cells, or help clean up environmental toxins by using the
toxins as fuel.

Authors on the paper include: Rawiwan Laocharoensuk, Jared Burdick,
and Joseph Wang. Their study is scheduled for the May 27 issue of ACS
Nano, a monthly journal. They also reported their findings in the
online edition of ACS Nano Carbon-Nanotube-Induced Acceleration of
Catalytic Nanomotors.

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Adapted from materials provided by the American Chemical Society