Vibrational Spectroscopy in Bioanalysis

Vibrational techniques undoubtedly have a main role in studying a variety of bioanalytical processes, from a pure molecule to a single cell. In this chapter, we address the fundamentals of linear and nonlinear techniques, namely, infrared, Raman, coherent anti-Stokes Raman scattering (CARS), vibrational sum frequency generation (Vib.-SFG), describing them in order of growing nonlinearity. We also discuss some of the aspects of surface enhanced Raman spectroscopy (SERS), focusing on its inherent nonlinear characteristics and its interface with the field of plasmonics. Then, we present a state-of-art of the main bioanalytical applications, highlighting the versatility and suitability of these techniques to study problems of different complexities and the possibility of some to reach point-of-care status. Finally, we offer a perspective on the near future of these techniques and their ability to continue permeating other fields of research.