Investigation of influence of drugs on cellular metabolism in 2Dc cell culture using surface-enhanced raman scattering

Raman spectroscopy (RS) is a powerful vibrational spectroscopic technique that provides molecular-level information from a sample without a label. Surface-enhanced Raman scattering (SERS) is a highly sensitive mode of Raman Spectroscopy and it can help to identify molecular composition on the surface or very close vicinity of noble metal particles with a size of fewer than two orders of magnitude in seconds. Metformin (MET) is a drug molecule, which affect mitochondrial respiratory chain complex I, cell proliferation, protein synthesis and gluconeogenesis. 6-Mercaptopurine (6-MP) has immunosuppressive features that conceivable regulated by its involvement with nucleic acid metabolism and protein synthesis in the series following antigen stimulation, and via its cytotoxic activity on cells. In this study, the potential of SERS to be able to monitor the effect of drugs on cell metabolism was investigated using metformin and 6-Mercaptopurine as model drugs. Two cell lines, A549 and Beas-2b, were chosen for the study. Gold nanoparticles with an average size of 50 nm were chosen as SERS substrates. Nucleic acids, amino acids and phospholipids peaks were changed in treatment of Metformin. The reason for this change MET mechanisms which inhibition of proliferation and protein synthesis and suppression of lipid and cholesterol biosynthesis. SERS peaks corresponding to nucleic acids and proteins were changed with the treatment of 6-Mercaptopurine. The observed spectral changes are attributed to the inhibition of de novo purine synthesis and protein synthesis. The changes in observed spectral pattern upon exposure of cells to drug molecules at increasing concentrations are attempted to relate the known drug metabolism mechanisms. The results demonstrate that SERS can be used to monitor the metabolic changes at cellular level upon exposing them to drug molecules as it is demonstrated in the case of MET and 6-MP.