Advanced experimental methods toward understanding biophysicochemical interactions of interfacial biomolecules by using sum frequency generation vibrational spectroscopy

Sum frequency generation vibrational spectroscopy (SFG-VS) has been demonstrated to be a powerful technique to study the interfacial structures and interactions of biomolecules at the molecular level. Yet most previous studies mainly collected the SFG spectra in the frequency range of 1500–4000 cm−1, which is not always sufficient to describe the detailed interactions at surface and interface. Thorough knowledge of the complex biophysicochemical interactions between biomolecules and surface requires new ideas and advanced experimental methods for collecting SFG vibrational spectra. We introduced some advanced methods recently exploited by our group and others, including (1) detection of vibration modes in the fingerprint region; (2) combination of chiral and achiral polarization measurements; (3) SFG coupled with surface plasmon polaritons (SPPs); (4) imaging and microscopy approaches; and (5) ultrafast time-resolved SFG measurements. The technique that we integrated with these advanced methods may help to give a detailed and high-spatial-resolution 3D picture of interfacial biomolecules.