Fig. 4.

Relative uptake of alkyne tagged fatty acids. Relative intensity (mean + standard deviation) of the total sum of the intensity of the alkyne stretching frequency at 2118 cm⁻¹ to the total spectral intensity for the total cellular area Raman mapped for HEK293T cells incubated for 4 h with 100 μM C14 alkyne, C16 alkyne or C18 alkyne, scaled to account for inherent intensity differences of the tags based on Fig. 1(b). Maps were acquired using a step size of 1 μm in x and y, 532 nm excitation, 100%/ca. 20 mW laser power, 1 s acquisition time and a spectral centre of 2000 cm⁻¹. Three maps were acquired per tag. Black = C14 tag; pink = C16 tag; blue = C18 tag.