Infrared microspectroscopy of individual human cervical cancer (HeLa) cells

We report infrared (IR) spectra observed for individual, cultured human cervical cancer (HeLa) cells. Spectra were collected microscopically, in reflection/absorption modes, from cells deposited and dried on microscope slides or from cells grown directly on slides. Within the spectra of the dried cells, significant spectral heterogeneity exists that was previously attributed to different stages of the cell cycle [Boydston-White. S., et al., Biospectroscopy 1999, 5, 219-227; Holman, H. Y., et al., Biopolymers Biospectrosc 2000, 57, 329-335; Tobin, M. J., et al., in First BASIE Workshop, Karlsruhe, Germany, 2003]. The results reported here confirm earlier findings and present the possibility of determining the abundance of cells within each stage of the cycle from the IR spectra. In an accompanying paper, we show that the spectra of cells in suspension exhibit spectral intensity distributions that are different from that of the dried cells. This result has far-reaching implications for the use of infrared microspectroscopy to screen dried cell preparations for the presence of abnormal cells.