Development of a quantitative approach to measure phospholipids in dried drops by Raman spectroscopy

Phospholipids, PL, such as the phosphatidylcholine PC(18:0/18:1), play a role in the structure of living cells and are suspected to be part of the development of some diseases, for example cancers. Mass spectrometry enables the structural analysis of PL in complex biological media but imaging mass spectrometry by MALDI-MS is rather limited for quantification purposes. Complementarily, Raman spectroscopy as a non invasive and non destructive method is a potential candidate to quantify and visualise the spatial distribution of the PL by molecular imaging. Unfortunately, the lack of specific chemical function in PL, compared to others biomolecules, limits the use of Raman spectroscopy in the identification process of those PL in complex biological samples. The results presented here belong to a first study of the application of the Raman analyses on dried residues of PL and mice brain tissue performed in the lab.