A review of applications of Raman spectroscopy in immunology

Vibrational spectroscopic techniques have recently gained increasing clinical importance as non-invasive, rapid and inexpensive methods to obtain information on the content of biological samples. For some time Raman spectroscopy has been involved in preclinical applications, mainly in the cancer space, with evolving applications towards new horizons in the dermatology and companion diagnostics arena. It is attractive as an analytical technique due to its exquisite sensitivity, label-free operation and low water detectivity such that in-vivo applications are possible. In cytometry, Raman spectroscopy has been applied to the analysis of single cells providing a label-free alternative to cell classification approaches in the laboratory. In this review we collate in-vitro, ex-vivo and in-vivo examples of research using Raman spectroscopy for the detection, quantification and analysis of immune signaling at the cellular level. While cancer biology has recently focussed on the role of immunological signals in the development of the disease, it is timely to examine these applications as research in this space evolves.