Photonic nanostructures as SERS substrates for reproducible characterization of bacterial spores

Surface enhanced Raman spectroscopy (SERS) has been used as a tool to investigate spectral differences of bacterial endospores. Ultimately, this method could be used as a smart and rapid on-site detector for biological warfare agents. However, due to the spectral complexity and the relative size of spores to the substrate features, a rigidly defined substrate is necessary for reproducible characterization. We are investigating 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. The key aspects of this work include discerning what architectural pattern provides the largest enhancement and reproducibility when sampling the spore coat and whether some method of immobilization, or attraction, of the spores to the surface is necessary. We will present preliminary results of bacterial spore identification as well as a comparison of the substrates studied.