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Photo by Stuart Wolpert
Giovanni Zocchi, assistant professor of physics and member of
the California NanoSystems Institute, has created a nanosensor that
uses a single molecule as a detector. The sensor could detect diseases
and genetic abnormalities and could gauge how cells respond to medications,
all at a microscopic level.
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small but powerful
Disease detection with a single molecule
by stuart wolpert
ucla today
Physicists at UCLA have created a first-of-its-kind nanoscale sensor
that uses a single molecule less than 20 nanometers long — more
than 1,000 times smaller than the thickness of a human hair — as
its primary detector.
One day, this miniscule machine could be used to detect the earliest
signs of genetic diseases or identify a growing number of cancers for
which genetic markers are known, said Giovanni Zocchi, an assistant professor
of physics and member of the California NanoSystems Institute (CNSI),
who led the research team.
“This single-molecule sensor could be an important component of
‘a lab on a chip’ technology for doing chemical analysis on
a chip,” Zocchi said. “The largest potential applications
for this sensor may be in the drug discovery process,” where speed
in gauging how cells respond to experimental drugs is critical.
Zocchi’s nanoscale sensor uses a single molecule to recognize
the presence of a specific short sequence in a mixture of DNA or RNA molecules
— a feat that he equates with finding a needle in a haystack.
“When a target molecule binds to the probe in the sensor, the
probe molecule changes shape, and in its new conformation, pulls on the
sensor,” he explained. “Instead of detecting the presence
of the target, we detect the changing conformation of the probe when the
target binds to it.”
What’s remarkable, Zocchi said, is that a single molecule can
actually move the much heavier sensor. Relatively speaking, it’s
as if one person were able to move a mountain. “But mass is of no
consequence at these miniscule scales,” he said.
Zocchi’s team plans to use the nanoscale sensor in experimental
leukemia research to test whether the sensor’s high sensitivity
can detect a recurrence of cancer at an earlier stage than is now possible.
“If we can increase the sensitivity of the detector, then it may
be possible to detect genetic diseases at an earlier stage,” Zocchi
said. “It may become possible to diagnose the presence of an abnormality
in DNA at an early stage, or the expression of a certain gene that should
not be expressed.”
Zocchi, who joined UCLA’s faculty in 1999 after conducting research
at the Niels Bohr Institute in Copenhagen, Denmark, is exuberant about
the future of nanotechnology research.
Work on the single molecule sensor, which was funded by the NSF and
reported recently in the Proceedings of the National Academy of Sciences,
is just one of the promising new developments that UCLA and UC Santa Barbara
scientists at CNSI are pursuing that could revolutionize health care,
information technology, aerospace and manufacturing, among other fields,
and propel California’s economy into a prosperous future. For example,
the single molecule sensor may be used one day to detect minute traces
of biological weapons, Zocchi hypothesizes.
“Ultimately these efforts will lay the groundwork for creating
artificial systems with more and more of the characteristics that have
been unique to living things,” he said. “Economy of scale
allows nature to pack the most elaborate laboratory on Earth into a single
bacterial cell; in the future, artificial systems may approach similar
complexity.”
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