Photodiagnosis using Raman and surface enhanced Raman scattering of bodily fluids.

Raman spectroscopy is the measure of inelastic scatter and has been described since 1928. It is particularly useful for medical applications because the scattered radiation measured is unique for each biomolecule. The aim of this study was to review works published in Raman scattering and surface enhanced Raman scattering (SERS) on bodily fluids. The main Raman studies have concentrated on the detection of metabolites in the aqueous humour, urine and blood-based fluids and on drugs in the latter. Other bodily fluids are also studied, e.g. vitreous humour. The Raman intensity is inherently weak. SERS provides immense amplification of the Raman signal and so it can be used for the detection of small concentrations of biochemicals. This is achieved by using nano-structured metal particles. Studies have been done to describe how the amino acids of bodily fluids interact with the nano-metal substrates. Applications of SERS in the medical field include: protein identification, illicit drugs in bodily fluids and its use as a reporter in immunoassay and DNA hybridisation. For both normal Raman and SERS the experimental design has also been reviewed. It clearly shows that the choice of wavelength is important to reduce the shot noise associated with fluorescence. Most experimental parameters show that these techniques can be useful and quick in vitro tests.