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membrane mimics biological behavior of ion channels
Kloeppel, Physical Sciences Editor
photo to enlarge
by L. Brian Stauffer
Leburton, the Stillman
Professor of Electrical and Computer Engineering
at Illinois, led the team that designed a semiconductor
membrane that could offer more flexibility and
better electrical performance than biological membranes.
CHAMPAIGN, Ill. —
A semiconductor membrane designed by researchers at the University of
Illinois could offer more flexibility and better electrical performance
than biological membranes. Built from thin silicon layers doped with
different impurities, the solid-state membrane also could be used in
applications such as single-molecule detection, protein filtering and
“By creating nanopores in the membrane, we can use the membrane
to separate charged species or regulate the flow of charged molecules
and ions, thereby mimicking the operation of biological ion channels,”
said lead researcher Jean-Pierre Leburton, the Stillman
Professor of Electrical and Computer Engineering at Illinois.
Leburton, with postdoctoral research associate Maria Gracheva and graduate
student Julien Vidal, simulated the operation of the semiconductor membrane
at a number of electrostatic potentials. They report their findings
in a paper accepted for publication in the journal Nano Letters, and
posted on the journal’s Web site.
In the researchers’ model, the nanopore-membrane structure is
made of two layers of silicon, each 12 nanometers thick, with opposite
(n- and p-) doping. The electrostatic potential is positive on the n-side
and negative on the p-side of the membrane.
The nanopore has an hourglass shape, with a neck 1 nanometer in diameter
and openings on each side of the membrane 6 nanometers in diameter.
The “size” of the nanopore can be changed by changing the
electrostatic potential around it.
By controlling the flow of ions, the artificial nanopore offers a degree
of tunability not found in biological ion channels, said Leburton, who
also is a researcher at the university’s Beckman
Institute, the Coordinated Research
Laboratory, and the Micro and
In addition to serving as a substitute for biological ion channels,
the solid-state nanopore and membrane could be used in other applications,
including sequencing DNA.
semiconductor technology to sequence the DNA molecule would save time
and money,” Leburton said. “By biasing the voltage across
the membrane, we could pull DNA through the nanopore. Since each base
pair carries a different electrical charge, we could use the membrane
as a p-n junction to detect the changing electrical signal.”
Funding was provided by the National Science Foundation and the National
Institutes of Health.
Editor’s note: To reach Jean-Pierre Leburton,
call 217-333-6813; e-mail: firstname.lastname@example.org.
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