Special nanoscale imaging modes in biological electron microscopy

Wednesday, October 26, 2011 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center	NIBIB	IMAG-33

Authors

• A Sousa
• M Aronova
• G Zhang
• R Leapman

Abstract

A wide range of imaging modes in the electron microscope can provide unique structural information about cells and macromolecular assemblies. Here we present three specialized, unconventional imaging modes currently in use in our laboratory. (1) Dark-field scanning transmission electron microscopy (STEM) is an established and powerful method with which one can obtain the mass of isolated molecular assemblies. Significantly, this technique provides a unique means to determine the mass per length of filamentous structures such as Alzheimer's amyloid fibrils. (2) Axial bright-field STEM tomography is a technique recently developed in our laboratory that allows the 3D reconstruction of thick (1 micrometer) sections of resin-embedded biological specimens. This capability facilitates analysis of larger and more complex cellular structures than what is typically feasible with conventional electron tomography. (3) Energy-filtered transmission electron microscopy (EFTEM), which is based on collecting inelastically scattered electrons passing through the specimen and carrying quantitative chemical information about the specimen. Imaging contrast agents, such as nanoparticles can thus be characterized and evaluated for their elemental composition before using them in cell/organelle labeling. Also, EFTEM together with electron tomography were used to investigate the chromatin structure in the compartments of the cell nucleus.

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