a)
100 nm 100 nm 100 nm
b) c)
world news
RAMAN SPECTROSCOPY
Plastic SERS sensor is mass-producible, disposable
In surface-enhanced Raman spec-
troscopy (SERS), a sensing surface is
modified by roughening or the addition
of nanoscale features; the modification
boosts Raman scattering from molecules
on the surface by many orders of magni-
tude. This highly sensitive form of spec-
troscopy has been commercialized and
widely used to sense minute amounts of
organic substances such as foods, drugs,
bacteria, pesticides, indicators of cancer,
and many others.
In 2006, Mesophotonics (Southamp-
ton, England), a spinoff of the Univer-
sity of Southampton, introduced the first
all-in-one SERS toolkit, which included
a spectrometer, SERS substrates, and
software; the nanostructured, silicon-
based “Klarite” substrates provided
highly reproducible SERS signals, leading
to the wide use of SERS in the real
world. (Mesophotonics is now a part of
Renishaw Diagnostics; Klarite sensors are
used in pharmaceuticals and biosensing.)
Now, Martin Charlton, who founded
Mesophotonics, and his team at the Uni-
versity of Southampton have developed a
version of the Klarite substrate that is not
only more sensitive, but is also disposable. 1
They achieved this by using plastic instead
of silicon as the sensor base, using roll-
to-roll (R2R) and sheet-level nanoimprint
fabrication techniques to replicate SERS
sensors in potentially large quantities.
The original Klarite surface contains
gold-coated inverted pyramidal pits
A nanopyramidal SERS structure is embossed by a silicon master into UV-curable polymer
using either a roll-to-roll (R2R) or sheet method. Scanning-electron micrographs show inverted
pyramids (after a 300 nm gold film is deposited) for the silicon master (a), a polymer R2R
replica (b), and a polymer sheet-level replica (c). (Courtesy of the University of Southampton)
