Fig. 2
Mean Raman spectra of Treg Donor 5 on days 5–15 post-activation, with restimulation on day 11. The spectral intensities are normalized to nucleic acids, wherein for each Raman shift, the relative intensity on the vertical axis is the ratio of its mean spectral intensity to the intensity of the most intense peak within a neighborhood (defined as \(\pm\) 2 wavenumbers on either side) of the 782 cm-1 peak, which is a nucleic acid band (DNA, RNA, nucleotide bases). The insets are zoomed in plots at different biologically important regions of the spectrum which vary along the culturing timeline: (A) a phosphatidylinositol band around 415 cm-1 and a cholesterol band around 418 cm-1; (B) a phenylalanine band around 1003 cm-1; and (C) a protein band around 1450 cm-1.