Fig. 3.

Intracellular uptake of alkyne tagged fatty acids. White light image of cell region mapped (a), false colour map of the same region showing the intensity of the 2118 cm⁻¹ alkyne band (b) and examples of a high intensity spectrum (blue arrow in (b) and blue spectrum) and a low intensity spectrum (pink arrow in (b) and pink spectrum) (c) for HEK293T cells incubated for 4 h with 100 μM C14 alkyne tagged fatty acid. The same information is given for HEK293T cells incubated for 4 h with 100 μM C16 alkyne tagged fatty acid (d–f) and HEK293T cells incubated for 4 h with 100 μM C18 alkyne tagged fatty acid (g–i). 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. Scale bar = 20 μm. False colour image numbers on axis represent microns. Spectra were offset for clarity.