Mapping sub-cellular protein aggregates and lipid inclusions using synchrotron ATR-FTIR microspectroscopy.

Visualising direct biochemical markers of cell physiology and disease pathology at the sub-cellular level is an ongoing challenge in the biological sciences. A suite of microscopies exists to either visualise sub-cellular architecture or to indirectly view biochemical markers (e.g. histochemistry), but further technique developments and innovations are required to increase the range of biochemical parameters that can be imaged directly, in situ, within cells and tissue. Here, we report our continued advancements in the application of synchrotron radiation attenuated total reflectance Fourier transform infrared (SR-ATR-FTIR) microspectroscopy to study sub-cellular biochemistry. Our recent applications demonstrate the much needed capability to map or image directly sub-cellular protein aggregates within degenerating neurons as well as lipid inclusions within bacterial cells. We also characterise the effect of spectral acquisition parameters on speed of data collection and the associated trade-offs between a realistic experimental time frame and spectral/image quality. Specifically, the study highlights that the choice of 8 cm