Tensor Tomographic Small-Angle X-ray Scattering for the Quantitative Characterization of Periodic Nanostructures in Neurological Tissues
Selma Sejdic
11:15 - 12:15 Wednesday 27 May 2026 Myelin, the multilamellar sheath surrounding axons, is essential for rapid neuronal communication and overall brain function. Structural alterations of myelin are a hallmark of numerous neurodegenerative diseases, yet its nanoscopic organization remains challenging to quantify in situ.
Although techniques such as magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) have advanced the study of white-matter microstructure, their spatial resolution is limited to the micrometer or millimeter scale. In contrast, other ex vivo techniques, including electron microscopy and histology, provide higher resolution but rely on invasive sectioning and extensive sample preparation.
Small-angle X-ray scattering (SAXS) offers a complementary route to probe nanoscale periodicities in soft and biological matter. In myelinated tissue, the regular lamellar spacing of lipid bilayers produces distinct scattering peaks whose intensity and orientation reflect both myelin structure and axonal alignment. Extending SAXS into a tomographic and tensor-based framework enables reconstruction of three-dimensional anisotropic scattering distributions, allowing volumetric characterization of structural order within intact tissue samples. In addition, radiation damage effects were systematically investigated at the DESY synchrotron setup through a cross-comparison of brain tissue samples fixed in formaldehyde for different durations.
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[2] Zirui Gao, Manuel Guizar-Sicairos, Viviane Lutz-Bueno, Aileen Schroeter, Marianne Liebi, Markus Rudin, and Marios Georgiadis. High-speed tensor tomography: iterative reconstruction tensor tomography (irtt) algorithm. Foundations of Crystallography, 75(2):223–238, 2019.
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Institute of Solid State Physics
