Tailored plasmonic nano architectures for surface enhanced Raman spectroscopy and its applications in probing biomolecular interactions

Abstract

This thesis shows the utility of vibrational spectroscopy to study biomolecular interactions, including protein-small molecule interactions which have important implications in the drug development process and pharmaceutical industries. Vibrational spectroscopy can be broadly divided into two complimentary techniques infrared (IR) and Raman. Raman scattering captures vibrational modes of molecules, materials and biomolecules in an aqueous medium with negligible interference from water. The inherent weak signal in Raman scattering restricts its usage. This issue can be resolved through Surface-enhanced Raman spectroscopy (SERS). One of the foremost advantages of SERS is the rich blend of high sensitivity and chemical imaging capability, which vastly caters to the needs of ultra-trace analysis of molecules. The vibrational spectroscopic techniques discussed in the chapters of the thesis are mainly Raman spectroscopy, Surface-enhanced Raman spectroscopy (SERS) and visible Resonance Raman whose detailed descriptions are given in Chapter 1. An introduction to plasmonic nanostructures for SERS, reported in the literature, have also been provided. The thesis has been primarily divided into two parts. The first part describes tailored plasmonic nano architectures as SERS sensors. The second part of the thesis highlights the importance of SERS and Raman in the field of biology to understand different molecular mechanisms involved when small molecules interact with different kinds of proteins. The use of SERS is relatively new and unexplored in the area of protein-ligand interactions. Trace detection of molecules, biomolecule sensing and characterization are some other fields where SERS is advantageous.