In this work we perform correlated structural and optical studies of single nanoparticles as well as explore the generality
of SMSERS. First, wide-field plasmon resonance microscopy is used to simultaneously determine the LSPR spectra of
multiple Ag nanoprisms, whose structure is determined using TEM. Next, the structure-property relationships for well-defined
and easily-controlled nanoparticle structures (e.g. monomers, dimers, and trimers) are studied using correlated
TEM, LSPR, and SERS measurements of individual SERS nanotags. We present the SER spectrum of reporter
molecules on a single nanotag comprised of a Au trimer. It was determined that of 40 individual nanotags, just 19
exhibited SERS. The remaining nanoparticles were established by TEM to be monomers. These results demonstrate that
SERS signal is observed from individual nanotags containing a junction or hot spot. Lastly, we explore crystal violet, a
triphenyl methane dye that was used in the seminal SMSERS investigations, and re-examine single-molecule sensitivity
using the isotopologue approach.
Detection tags based upon surface enhanced Raman scattering provide an alternative to the widely used fluorescence methods. Several aspects of these tags are presented in this report. The tags can be made to display many different spectra, thus they can be used for multiplexed detection schemes. They generate a large enough number of photons to be readily detected, and spectra acquired from mixtures of tags can be analyzed giving accurate amounts of the components. The surface of the tags can be easily modified to present common biological molecules (streptavidin and analogues). Finally, we demonstrate their use to quantitatively detect interleukin-4 (IL4) and interleukin-7 (IL7) in a microarray format.
At Nanoplex Technologies, Inc. we have developed Nanobarcodes particles, which are encodeable, machine-readable, durable, sub-micron sized taggants which have application for document and product security. We will present results on the use of Nanobarcodes particles in a number of authentication and anti-counterfeiting applications. We also focus on the software component in recognition of particles imaged against varied backgrounds.