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Poster PresentationDetermining SERS cross-section of amino acids for protein characterizationRachael BridgmanZachary Schultz, Dept. of Chemistry and Biochemistry, University of Notre DameAdvisor: Zachary Schultz, Dept. of Chemistry and Biochemistry, University of Notre DameProteins are the building blocks of all life forms and are composed of amino acids. The chemicalstructure of proteins is important for understanding their function. The amino acid sequencedictates protein structure. Raman is a chemically specific method that can be used to identify theamino acids in a protein. Raman is a low signal experiment; however, the signals can beenhanced using gold and silver nanostructures, commonly referred to as surface enhancedRaman spectroscopy (SERS). The signal intensities observed in SERS are often different thanregular Raman. Determining each amino acid’s SERS cross-section provides a measure of howlikely an amino acid will scatter compared to another. However, it has been difficult to develop areliable process for determining the SERS cross-section of molecules. The goal of this projectwas to determine the SERS cross-section of all 22 amino acids and to use this information tospecify amino acid contributions to the SERS spectrum of proteins like Bovine Serum Albumin(BSA). Toward this goal, we quantified the regular Raman cross section of each amino acid as asolid and in aqueous solution. These results serve as a reference upon which to analyze thebands observed in SERS. The empirical data was used to dissect BSA’s spectra and determinewhich amino acids were detected in the protein. This analysis suggested that the amino acidresidues histidine, serine and phenylalanine are present in BSA. Future work quantifying theSERS response of each amino acid will help understand differences in the conventional Ramanand SERS spectrum of proteins.29