Fig. 1: Spectra of saturated fatty acids are affected by the surrounding lipid environment.
From: Raman microscopy-based quantification of the physical properties of intracellular lipids
a, b Comparison of Raman spectra of saturated (a) and unsaturated (b) fatty acid between in vivo and in vitro. HeLa cells treated with indicated deuterium-labeled fatty acids (30 μM) for 24 h were fixed and observed using Raman microscopy. Representative measured spectra at LDs (represented by red crosshair 1 in the bottom images) are shown in black lines, and the results of the best-fitted in vitro spectra, background spectra, baseline drifts, and their summations are shown in dashed red lines, dashed gray lines, dashed gray straight lines, and solid red lines, respectively. Spectra at red crosshair 2 in the bottom images were used as the background spectra for the fittings. Measurement of multiple cells and samples resulted in similar results. Scale bars indicate 10 μm. c, d Bright-field images and Raman spectra of C16:0(d31), C18:1(d0), and their mixture. The Y-axis of each spectrum was arbitrarily scaled to make the comparison clearer by equalizing the heights of spectra derived from C–D stretching (C16:0[d31] and the C18:1[d0]/C16:0[d31] mixture) and C–H stretch (C18:1[d0] and the C18:1[d0]/C16:0[d31] mixture). The magnified graph of the area framed by the dashed red square in (d) is shown in (e).
