FTIR and SXRF imaging of amyloid-β plaques in the hippocampus of a murine model of AD. (a) Hematoxylin and eosin (H&E) histology of the hippocampus shows the region analyzed with FTIR and SXRF (white box). The locations of hippocampus substructures have been labeled, dentate gyrus (DG), hilus (Hil), and corpus ammonis sector 1 neurons (CA1). FTIR spectroscopic imaging of the distribution of (b) aggregated protein, (c) lipid ester, and (d) lipid methylene groups in the hippocampus. (e) UV autofluorescence image of amyloid-β plaque location. SXRF elemental mapping of the distribution of (f) Fe, (g) Cu, and (h) Zn in hippocampal region. (i−l) Close-up view of the distribution of Fe, Cu, and Zn in individual plaque (shown by large white arrow in panels (b−h) and (l) an overlay of Fe, Cu, and Zn. (m−o) High-resolution synchrotron radiation FTIR spectroscopic mapping of the same plaque shown in panels (i−l), highlighting the distribution of (m) aggregated protein, (n) lipid ester, and (o) lipid methylene in an individual plaque. All images collected from the same tissue section. Scale bars are (a) 500 µm, (b−h) 200 µm, and (i−o) 20 µm. Adapted from Summers et al. [50].