Surface Enhanced ROA Using Nanoshells

This Phase I STTR proposal involves the design and feasibility testing of a nanoshell-based substrate for the surface enhancement of Raman Optical Activity (ROA). ROA is an extremely sensitive measurement of the vibrational optical activity that can provide molecular stereochemical information of optically active chiral molecules. ROA measurements have existed for the past thirty years but have not been widely used because of sensitivity limitations and the difficulty of making such a sensitive measurement. Nanoshells, a dielectric core surrounded by a thin metallic shell, have previous been shown to provide an electromagnetic near-field that can be engineered for significant surface enhanced Raman scattering (SERS), providing enhancements of at least 10^8 from individual nanoshells. Additionally, nanoshells can be engineered to provide these enhancements at desired wavelengths, including the near-infrared, which allows Raman sensing for biomolecules that otherwise have significant fluorescence background in the visible spectra. This objective of this proposal is to unlock the commercial potential of ROA by using a nanoshell-based substrate to achieve a surface enhancement of ROA (SEROA) signals. This proposed research will demonstrate the feasibility of using the strong electromagnetic near-field of nanoshells to enhance the ROA of optically active chiral molecules in the near-infrared