A carbon nanotube treated with a capture agent, in yellow, can bind with and detect the purple-colored target protein—this changes the electrical resistance of the nanotube and creates a sensing device. Graphic courtesy of Oregon State University |
Researchers
at Oregon State University have tapped into the extraordinary power of
carbon “nanotubes” to increase the speed of biological sensors, a
technology that might one day allow a doctor to routinely perform lab
tests in minutes, speeding diagnosis and treatment while reducing costs.
The
new findings have almost tripled the speed of prototype
nano-biosensors, and should find applications not only in medicine but
in toxicology, environmental monitoring, new drug development and other
fields.
The
research was just reported in Lab on a Chip, a professional journal.
More refinements are necessary before the systems are ready for
commercial production, scientists say, but they hold great potential.
“With
these types of sensors, it should be possible to do many medical lab
tests in minutes, allowing the doctor to make a diagnosis during a
single office visit,” said Ethan Minot, an OSU assistant professor of
physics. “Many existing tests take days, cost quite a bit and require
trained laboratory technicians.
“This
approach should accomplish the same thing with a hand-held sensor, and
might cut the cost of an existing $50 lab test to about $1,” he said.
The
key to the new technology, the researchers say, is the unusual
capability of carbon nanotubes. An outgrowth of nanotechnology, which
deals with extraordinarily small particles near the molecular level,
these nanotubes are long, hollow structures that have unique mechanical,
optical and electronic properties, and are finding many applications.
In
this case, carbon nanotubes can be used to detect a protein on the
surface of a sensor. The nanotubes change their electrical resistance
when a protein lands on them, and the extent of this change can be
measured to determine the presence of a particular protein—such as serum
and ductal protein biomarkers that may be indicators of breast cancer.
The
newest advance was the creation of a way to keep proteins from sticking
to other surfaces, like fluid sticking to the wall of a pipe. By
finding a way to essentially “grease the pipe,” OSU researchers were
able to speed the sensing process by 2.5 times.
Further
work is needed to improve the selective binding of proteins, the
scientists said, before it is ready to develop into commercial
biosensors.
“Electronic
detection of blood-borne biomarker proteins offers the exciting
possibility of point-of-care medical diagnostics,” the researchers wrote
in their study. “Ideally such electronic biosensor devices would be
low-cost and would quantify multiple biomarkers within a few minutes.”
This
work was a collaboration of researchers in the OSU Department of
Physics, Department of Chemistry, and the University of California at
Santa Barbara. A co-author was Vincent Remcho, professor and interim
dean of the OSU College of Science, and a national expert in new
biosensing technology.
The research was supported by the U.S. Army Research Laboratory through the Oregon Nanoscience and Microtechnologies Institute.
About
the OSU College of Science: As one of the largest academic units at
OSU, the College of Science has 14 departments and programs, 13
pre-professional programs, and provides the basic science courses
essential to the education of every OSU student. Its faculty are
international leaders in scientific research.
Increasing the detection speed of an all-electronic real-time biosensor
