Abstract
It is well recognized that interfacial structure of biomolecules plays crucial role in controlling their functions. Thus, it is essential to obtain information of molecular structure. Vibrational spectroscopy, which has been well used in characterization of molecular structure, is one of the useful techniques to study the structure and functions of protein and other biomaterials. However, conventional vibrational spectroscopy suffers from sensitivity too poor to detect the signal from the monolayer. In this review, we present applications of two vibrational techniques with high surface sensitivities, namely, surface enhanced infrared absorption spectroscopy (SEIRAS) and sum frequency generation (SFG) spectroscopy, for the functional studies of biointerfaces.