Figure 3.

Population-wide changes in Raman spectra during differentiation. Average baseline-subtracted Raman spectra of 32D cells on days 0, 1, 4, 7, and 14 following induction of neutrophilic differentiation showed pronounced changes in several peaks corresponding to nucleic acids and lipids. Raman spectra were acquired at room temperature using a Horiba LabRAM HR confocal Raman microscope (Horiba Scientific) equipped with a Horiba Synapse back-illuminated, deep-depletion CCD camera. A 785 nm laser (15 mW power at the sample, theoretical spot diameter of 958 nm) was focused on the center of each cell for 40 s through an Olympus 60× water-dipping objective (2 mm working distance). The grating was set to 300 grooves/mm, and the pinhole and slit sizes were set to 500 and 100 μm, respectively.