Infrared spectroscopy of cultured cells: II. Spectra of exponentially growing, serum-deprived and confluent cells

Abstract Infrared microspectroscopy (IR-MSP) is a spectroscopic technique that is able to monitor cell differentiation, maturation, and progression through the cell cycle. In order to establish this technique as a diagnostic tool in cellular biology and pharmacology, spectral patterns indicative of the stages of cell proliferation need to be collected. Thus, we have embarked on a systematic study of the effects of cell division and cell cycle progression on the infrared spectra of cells. In this paper, we modulated the level of cell proliferation and report the effects of this modulation on the observed infrared spectra of the cells. The modulation was achieved by serum deprivation of the growing cells, or by having the cell culture reach confluence. The progression of the cells through the cell cycle was monitored via flow cytometry, and correlated with changes in IR-MSP features in the spectral signatures due to nucleic acids (1250–1000 cm −1 ). In both these experiments, the majority of cells are in the G0/G1 stages, 3 with only a small percentage in the S and G2 phases. Nevertheless, spectral differences could be observed and interpreted in terms of the spectral changes of cellular DNA.