Artistic illustration
showing an ultrasensitive detection platform termed slippery liquid
infused porous
surface-enhanced Raman scattering (SLIPSERS). In this platform,
an aqueous or oil
droplet containing gold nanoparticles and captured analytes is allowed
to evaporate on a
slippery substrate, leading to the formation of a highly compact
nanoparticle
aggregate for surface enhanced Raman scattering (SERS) detection.
Image: Shikuan
Yang, Birgitt Boschitsch Stogin, and Tak-Sing Wong/Penn State
(January 11, 2016) A
technique that combines the ultrasensitivity of surface-enhanced Raman
scattering (SERS) with a slippery surface invented by Penn State researchers
will make it feasible to detect single molecules of a number of chemical and
biological species from gaseous, liquid or solid samples. This combination of
slippery surface and laser-based spectroscopy will open new applications in
analytical chemistry, molecular diagnostics, environmental monitoring and
national security.
The researchers, led by Tak-Sing Wong, assistant professor
of mechanical engineering and the Wormley Family Early Career Professor in Engineering,
call their invention SLIPSERS, which is a combination of Wong's slippery
liquid-infused porous surfaces (SLIPS), a biologically inspired surface based
on the Asian pitcher plant, and SERS.
"We have been trying to develop a sensor platform that
allows us to detect chemicals or biomolecules at a single-molecule level
whether they are dispersed in air, liquid phase, or bound to a solid,"
Wong said. "Being able to identify a single molecule is already pretty
difficult. Being able to detect those molecules in all three phases, that is
really challenging."
Wong needed the help of postdoctoral fellow Shikuan Yang to
combine SERS and SLIPS into a single process. Yang was trained in Raman
spectroscopy in the characterization laboratory of Penn State's Materials
Research Institute. His expertise in the SERS technique and Wong's knowledge of
SLIPS enabled them to develop the SLIPSERS technology. Their work appeared
online on December 31, 2015 in the Proceedings of the National Academy of
Sciences.