The Army has a need for an accurate, fast, reliable and robust means to identify and quantify defense related materials.
Raman spectroscopy is a form of vibrational spectroscopy that is rapidly becoming a valuable tool for homeland defense
applications, as it is well suited for the molecular identification of a variety of compounds, including explosives and
chemical and biological hazards. To measure trace levels of these types of materials, surface enhanced Raman scattering
(SERS), a specialized form of Raman scattering, can be employed. The SERS enhancements are produced on, or in
close proximity to, a nanoscale roughened metal surface and are typically associated with increased local electromagnetic
field strengths. However, before application of SERS in the field and in particular to biological and other
hazard sensing applications, significant improvements in substrate performance are needed. In this work, we will report
the use of several SERS substrate architectures (colloids, film-over-nanospheres (FONs) and commercially available
substrates) for detecting and differentiating numerous endospore samples. The variance in spectra as obtained using
different sensing architectures will also be discussed. Additionally, the feasibility of using a modified substrate
architecture that is tailored with molecular recognition probe system for detecting biological samples will be explored.
We will discuss the progress towards an advanced, hybrid molecular recognition with a SERS/Fluorescence nanoprobe
system including the optimization, fabrication, and spectroscopic analysis of samples on a commercially available
substrate. Additionally, the feasibility of using this single-step switching architecture for hazard material detection will
also be explored.