Quantitative Raman spectroscopy offers a means of estimating concentrations of protein variants. The Raman spectrum can be a fingerprint of an individual molecule and features unique to functional groups. In conjunction with robust data analysis such as principal component analysis (PCA), chemometric assessment of a sample can be performed. As an optical technique, this approach can yield high-throughput with robust instrumentation that can be deployed in the field. Some facets of instrument miniaturization have already been accomplished. In order to deal with realistic sample sizes, surface enhanced Raman spectroscopy (SERS) can be employed. Using this approach, we propose to develop instrumentation for reproducible, high-throughput protein variant quantitation. Our approach relies on a proprietary substrate Lexitek is developing for SERS that can be inexpensively fabricated and is uniform and reproducible. The substrate has high enhancement and the unique capability for doing separation and detection in situ. As any amount of admixture separation increases the SNR of the chemometric process, our approach has a dimension not shared by other SERS assays that will enable development of a range of assays for protein variants.
Keywords: Protein Variant, Polymorphism, Quantitative Spectroscopy, Surface-Enhanced Raman Scattering, Molecular Diagnostics, Proteomics
