May 9, 2005
Nanotechnology grant will support work on
new sensor technology
By Tim Stephens
The National Academies Keck Futures Initiative has awarded
a $50,000 grant for nanotechnology research to Holger Schmidt,
assistant professor of electrical engineering.
Photo: Tim Stephens
Schmidt will work with Xing Su, a collaborator based in Santa
Clara, to develop a new type of sensor technology for medical
and biological analysis.
The project is one of 14 to receive competitive seed grants
this year from the National Academies Keck Futures Initiative
for interdisciplinary research on nanoscience and nanotechnology.
The initiative, funded by the W. M. Keck Foundation, aims to
stimulate interdisciplinary research at the most exciting frontiers.
The new sensor technology envisioned by Schmidt and Su would
enable the optical detection of specific molecules with single-molecule
sensitivity using a compact chip-based device. Schmidt's lab
has developed integrated optical waveguides with liquid cores,
enabling light propagation through tiny volumes of liquids on
a chip. Su works with composite nanoparticles that can be used
to amplify optical signals through an effect known as surface-enhanced
Raman scattering (SERS). The researchers plan to combine the
two technologies to create an "integrated biophotonic Raman
"The basic idea is that if you shine light on a molecule
it will vibrate and scatter light in a way that is characteristic
for each type of molecule. This scattered light is very weak,
but if the molecules are bound to a nanoparticle, the optical
signal is amplified enough to be detectable," Schmidt said.
Su has developed a novel type of hybrid inorganic nanoparticles
that produce large Raman scattering signals. Schmidt is also
collaborating with Jin Zhang, professor of chemistry and biochemistry
at UCSC, who is investigating other kinds of nanoparticles,
such as silver aggregates.
"One nice thing about our approach is that it works with
a variety of nanoparticles," Schmidt said.
The standard apparatus for detecting SERS is a large Raman
microscope set up on a laboratory benchtop. With Schmidt's liquid-core
waveguides, however, the optical detection apparatus could be
integrated into a silicon chip along with the necessary electronics.
This approach could lead to low-cost, portable, and highly sensitive
biophotonic sensor devices for identifying proteins and other
biologically important molecules in small samples.
Schmidt said his collaboration with Su was the result of attending
a conference held last year by the Futures Initiative, called
"Designing Nanostructures at the Interface between Biomedical
and Physical Systems."
"We wouldn't have met otherwise, so I really value this
initiative, which is bringing together people from different
disciplines to generate these new directions and ideas,"
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