MEDICAL DEVICE INNOVATION - Medical Device Daily

MEDICAL DEVICE INNOVATION 2010
Hybrid bioelectronic platform
to yield better devices, tests
By LYNN YOFFEE
Medical Device Daily Staff Writer
The Holy Grail for just about any medical device is the
ability to seamlessly interact with human biology.
Scientists have yet to duplicate the sophistication of living
organisms. But combine electronic circuits with biological
components and the sky is the limit in terms of potential
medical applications for devices that yield drastically
increased efficiency.
Researchers at the Lawrence Livermore National
Laboratory (LLNL; Livermore, California) have just reported
a breakthrough in this area with the invention of a versatile
hybrid platform that uses lipid-coated nanowires to
build prototype bionanoelectronic devices.
“The idea came from looking at all the sophisticated
structures of biological proteins. These machines can do
things that rival or exceed the best we can do with the
macroscopic devices,” Aleksandr Noy, PhD, the LLNL lead
scientist on the project, told Medical Device Daily. “The
immediate task was to see if we can make them work in
electronic circuits. The longer-term goal would be to use a
combination of electronic and biological components to
create structures that can act as very efficient electronic
cellular interfaces, almost as a universal translator between
the cellular signaling and electronic signaling.”
Noy, who is also Theme Leader for the LLNL Physical
and Life Sciences Directorate, reported his complex findings
in the Proceedings of the National Academy of
Sciences.
“Obviously the work is an early stage demonstration,
so I can only speculate about practical use, but I would like
to see it used in smart prosthetics that could be controlled
directly by the nerve impulses from the brain,” he said.
Other applications resulting from the mingling of biological
components with electronic circuits run the gamut
from enhanced biosensing and diagnostic tools to
advanced neural prosthetics such as cochlear implants. The
platform could even increase the efficiency of computers.
Noy chose to work at the nanoscale to accomplish this
feat because “Nanoscale gives me the ability to use electronic
components that have the same size and scale as
biological molecules,” he said. “It makes the interface more
efficient and a lot less cumbersome.”
Many researchers have previously attempted to integrate
biological systems with microelectronics, but none
got to this point of seamless material-level incorporation.
“But with the creation of even smaller nanomaterials
that are comparable to the size of biological molecules, we
can integrate the systems at an even more localized level,”
Noy said.
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The new hybrid platform uses shielded nanowires that
are coated with a continuous lipid bilayer.
“We made silicon nanowire transistors on a chip, then
assembled a lipid membrane on the nanowire – essentially
mimicking the cell wall – and then we put the membrane
protein into the lipid bilayer to complete the device,” he
said.
The advantages of this technology platform over existing
electronic devices include reduced size, better sensitivity
as well as the potential to make much more sophisticated
circuitry in the future.
The LLNL team used lipid membranes, which are widespread
in biological cells. The membranes form a stable,
self-healing and almost impenetrable barrier to ions and
small molecules.
“These lipid membranes also can house an unlimited
number of protein machines that perform a large number
of critical recognition, transport and signal transduction
functions in the cell,” said Nipun Misra, a University of
California Berkeley graduate student and a co-author on
the paper.
What results is a shielded-wire configuration, which
allowed the researchers to use membrane pores as the only
pathway for the ions to reach the nanowires.
“This is how we can use the nanowire device to monitor
specific transport and also to control the membrane
protein,” Noy said.
By changing the gate voltage of the device, the team
showed that they can open and close the membrane pore
electronically.
Going forward, Noy said his group is worked to develop
various applications for the platform.
“I am thinking about this structure more as a platform
technology. We can put other membrane proteins in the
bilayer and make them perform other tasks,” he said. “The
long-term goal would be to develop viable bionanoelectronic
devices that perform functions that are robust
enough and complex enough to merit use in real applications;
obviously biomedical device use is a prime target.”
(This story originally appeared in the Aug. 17, 2009 edition
of Medical Device Daily.)
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