Raman Spectroscopy and Factor Analysis of Tumorigenic and Non-Tumorigenic Cells

Abstract

Raman spectra, measured for viable suspensions of M1 and MR1 cells, demonstrate spectral differences correlating with an increased protein and phospholipid content relative to DNA in the MR1 cells. The M1 and MR1 cell lines consist of rat fibroblast cells that have been transfected with a gene causing immortality, and the MR1 line has been further transfected with a gene causing tumor formation. The cell suspensions were prepared from monolayer cultures in the same phase of growth and remained viable throughout the experiment. The Raman data have been further examined by principal factor analysis with two approaches, (1) a constrained analysis to provide a relative contribution to the Raman data from cellular components, and (2) analysis of differences in the raw data files of the two cell lines. Utilizing the constrained principal factor analysis for the two cell lines analyzed separately provides a measure of the relative contribution of protein, lipid, DNA, RNA, and buffer to the cell Raman spectra. Factor analysis of M1 and MR1 Raman spectra analyzed together demonstrates that the two cell lines can be differentiated by Raman spectroscopy with no prior spectral processing.