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Quantitative imaging of biological structures in the electron microscope using elastic and inelastic scattering

Thursday, November 07, 2013 — Poster Session II

12:00 p.m. – 2:00 p.m.

FAES Academic Center (Upper-Level Terrace)

NIBIB

BIOENG-6

Authors

  • M.A. Aronova
  • A.A. Sousa
  • R.D. Leapman

Abstract

Transmission electron microscopy (TEM) provides a variety of nanoscale information about the organization and composition of biological structures. These capabilities are enhanced by incorporation of efficient electron detectors and digital acquisition systems. We have been developing two unconventional TEM techniques: (1) to detect and process inelastic scattering events in thin cellular sections using energy-filtering transmission electron microscopy (EFTEM); and (2) to obtain 3D structure from thick cellular sections by recording high-angle elastic scattering events in tomographic tilt series using scanning transmission electron microscopy (STEM), in which a nanometer-diameter focused probe is scanned across the specimen. In EFTEM, we utilize the information contained in core shell excitations to provide distributions of chemical elements in cellular organelles, and also combine the technique with tomography to determine 3D elemental maps. In STEM there are no imaging lenses after the specimen so that multiple inelastic scattering does not result in image blurring due to chromatic aberration. Here, we demonstrate the application of EFTEM to image distributions of phosphate-rich nucleic acid and sulfur-rich proteins in cells, as well as to image metals in bionanoparticles; and we demonstrate applications of STEM tomography to determine large structures at the nanoscale, such as entire synapses in brain.

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