CHAPTER 2: Optical Spectroscopies: Detection of Biological Species, Conformations and Interactions

A range of supramolecular interactions can give rise to changes in detected spectroscopic signals, which may, in certain cases, be used for sensing analytes and in optical imaging. Changes in conformation, orientation and concentration of specific analytes can be probed. Here an overview of a range of pertinent optical spectroscopies and underpinning principles adapted to study biological media are described. As well as more popular current spectroscopic techniques, notably a range of luminescence techniques (including time-resolved and polarization methods), emerging non-linear optical approaches are detailed. These are based on both electronic and vibrational spectroscopies, which hold great promise for future in situ studies, in particular when they are combined together to generate multimodal information in real-time monitoring where possible.