Investigating Photonic Nanostructures for Reproducible Characterization of Bacterial Spores

Raman spectroscopy has proven to be a plausible solution to the difficult challenge of on-site detection of biological threats. Adding to the challenge is the fact that many biological species, spores specifically, have relatively low scattering cross sections. The intrinsic need to detect these threats at low concentrations and in the presence of strong background signals necessitates the need for surface enhancement schemes. With an available technique to quickly identify bacterial spores, we are investigating the existence of spectral differences between target species in order to incorporate library technologies with the on-site sensor. We are examining many of the reported substrate classes such as: nano-sphere lithography (NSL), Film over nano-sphere (FONS), nano-shells, electrochemically roughened metals, and dispersed and immobilized colloids. Key aspects of this work include discerning what architectural features provide the largest enhancement and reproducibility. We will present preliminary results of bacterial spore identification as well as a comparison of the substrates studied. See also ADM001851, Proceedings of the 2003 Joint Service Scientific Conference on Chemical & Biological Defense Research, 17-20 November 2003. , The original document contains color images.