Structure and composition of myelinated axons: a multimodal synchrotron spectro-microscopy study

We report elemental mappings on the sub-cellular level of myelinated sciatic neurons isolated from wild type mice, with high spatial resolution. The distribution of P, S, Cl, Na, K, Fe, Mn, Cu was imaged in freeze-dried as well as cryo-preserved specimen, using the recently developed cryogenic sample environment at beamline ID21 at the European Synchrotron Radiation Facility (ESRF). In addition, synchrotron radiation based Fourier transform infrared (FTIR) spectromicroscopy was used as a chemically sensitive imaging method. Finally single fiber diffraction in highly focused hard X-ray beams, and soft X-ray microscopy and tomography in absorption contrast are demonstrated as novel techniques for the study of single nerve fibers.