Raman spectra of the monocytes were recorded with laser excitation at 532, 785, 830, and 244 nm. The measurements of the Raman spectra of monocytes excited with visible, near-infrared (NIR), and ultraviolet (UV) lasers lad to the following conclusions. (1) The Raman peak pattern of the monocytes can be easily distinguished from those of HeLa and yeast cells; (2) Positions of the Raman peaks of the dried cell are in coincidence with those of the monocytes in a culture cell media. However, the relative intensities of the peaks are changed: the peak centered around 1045 cm-1 is strongly intensified. (3) Raman spectra of the dead monocytes are similar to those of living cells with only one exception: the Raman peak centered around 1004 cm-1 associated with breathing mode of phenylalanine is strongly intensified. The Raman spectra of monocytes excited with 244-nm UV laser were measured on cells in a cell culture medium. A peak centered at 1485 cm-1 dominates the UV Raman spectra of monocytes. The ratio I1574/I1613 for monocytes is found to be around 0.71. This number reflects the ratio between proteins and DNA content inside a cell and it is found to be twice as high as that of E. coli and 5 times as high as that of gram-positive bacteria.
- Raman scattering
- UV resonance Raman spectroscopy
ASJC Scopus subject areas
- Materials Science(all)