X-Message-Number: 12456
From: Eugene Leitl <>
Date: Fri, 24 Sep 1999 16:11:50 -0700 (PDT)

Subject: Tiny pharmacies propelled through the body could result from Cornell 
breakthrough in molecular motors 

http://www.news.cornell.edu/releases/Sept99/bio_nano_mechanical.hrs.html

Fantastic voyage: Tiny pharmacies propelled through the body could
result from Cornell breakthrough in molecular motors

FOR RELEASE: Sept. 7, 1999

Contact: Roger Segelken
Office: (607) 255-9736
E-Mail: 

ITHACA, N.Y. --Coupling the organic and inorganic, biological
engineers at Cornell University have demonstrated the feasibility of
extremely small, self-propelled bionic machines that do their
builders' bidding in plant and animal cells, including those in
humans.

Such machines could travel through the body, functioning as mobile
pharmacies, for example, dispensing precise doses of chemotherapy
drugs exclusively to cancer cells.

The engineers' breakthrough is in integrating a living molecular motor
with a fabricated device at the "nano" scale, a few billionths of a
meter in size. The first integrated molecular motor, a molecule of the
enzyme ATPase coupled to a metallic substrate with a genetically
engineered "handle," ran for 40 minutes at 3 to 4 revolutions per
second, Carlo Montemagno and George Bachand report in the September
issue of the journal Nanotechnology (Vol. 10, No.3).

The ATPase molecules were produced by Escherichia coli bacteria that
were genetically engineered to include a gene sequence from the
thermophilic bacterium Bacillus PS3. With further genetic
manipulation, the Cornell engineers expect E. coli to turn out ATPase
molecules with tiny propellers -- making each a kind of nano-motorboat
-- as well as other useful structures, predicts Montemagno, an
assistant professor of agricultural and biological engineering.

The researchers concede they have not yet created an intelligent
nanomechanical machine, saying, "We have succeeded in establishing
biological and nanofabrication platforms for the production of
organic/inorganic hybrid nanoelectromechanical systems (NEMS), but we
have a long way to go before it's safe to turn these little machines
loose in the human body." For example, Montemagno says, engineers need
to determine the impact of waste products, such as heat and protons,
on the motors' performance and their surrounding environment.

"We believe this is a significant step toward the seamless integration
of nanoscale technologies into living systems and to the creation of
organic/inorganic intelligent systems," Montemagno said. He also
envisions ATPase motors pumping fluids, opening and closing valves in
microfluidic devices and providing mechanical drives for a new class
of nanomechanical devices.  The Cornell work with ATPase motors
recently was cited by Discover magazine as one of the most promising
new technologies of 1999.

Molecular motors are hardly new. For billions of years they have been
nature's way of accomplishing life's essential tasks at the atomic
level. The ATPase molecular motors are found in the membranes of
mitochondria, the microscopic bodies in the cells of nearly all living
organisms, as well as in chloroplasts of plant cells, where the enzyme
is responsible for converting food to usable energy. The moving part
of an ATPase is a central protein shaft (or rotor, in electric-motor
terms) that rotates in response to electrochemical reactions with each
of the molecule's three proton channels (comparable to the
electromagnets in the stator coil of an electric motor).

ATP (adenosine triphosphate) is the fuel for the molecular motor's
motion. Energy becomes available when atomic bonds between phosphate
atoms are broken during hydrolysis to convert ATP into ADP (adenosine
diphosphate). During ATP hydrolysis, the tail rotates in a
counterclockwise direction; it rotates clockwise during ATP synthesis
from ADP.

The Cornell engineers tagged the ATPase molecule's rotor with
fluorescent microspheres that are 1 micron (1 millionth of a meter) in
diameter and observed microsphere movement with a differential
interferometer and with a CCD (charge-coupled device) kinetics camera.

The "handle" for attaching the ATPase motor to the nanofabricated
metallic substrates is a synthetic peptide composed of histidine and
other amino acids. The histidine peptide allows the molecular motors
to adhere to nanofabricated patterns of gold, copper or nickel -- the
three standard contact materials in integrated circuits. The patterned
metal substrates were created by evaporative deposition at the Cornell
Nanofabrication Facility, which specializes in creating structures a
few nanometers in size.

Besides demonstrating that an organic molecular motor and an
inorganic, nanofabricated device can be integrated, the Cornell
engineers note, their system provides a platform for studying
fundamentals of ATPase's operation, which is not fully
understood. Their device will have more brawn than brains until the
molecular motors are attached to more advanced nanofabricated devices
that can provide directions.

"Our long-term objective is to utilize the best attributes of the
organic and inorganic worlds for NEMS that are powered by biological
motors and chemical energy sources," Montemagno said. "For a
technology that wasn't expected to produce a useful device before the
year 2050, I think we've made a pretty good start."

Studies of nanomechanical devices powered by biomolecular motors are
supported at Cornell by grants from the National Science Foundation
and the Department of Energy. Montemagno is a faculty member of
Cornell's College of Agriculture and Life Sciences and Bachand is a
research associate in his engineering laboratory.

-30-

Related World Wide Web sites: The following sites provide additional
information on this news release. Some might not be part of the
Cornell University community, and Cornell has no control over their
content or availability.

-- Nanotechnology journal (available only to subscribing institutions):

http://www.iop.org/EJ/S/3/97/?MIval=toc&key=0957-4484,10,3

--Montemagno lab: http://pomona.aben.cornell.edu/cmontemagno/index.htm

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