4D Electron Tomography
Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a movie of the object in motion, thus enabling studies of nonequilibrium structures and transient processes. The method was demonstrated using carbon nanotubes of a bracelet-like ring structure for which 4D tomograms display different modes of motion, such as breathing and wiggling, with resonance frequencies up to 30 megahertz. Applications can now make use of the full space-time range with the nanometer-femtosecond resolution of ultrafast electron tomography.
Additional Information© 2010 American Association for the Advancement of Science. Received 5 April 2010; accepted 19 May 2010. Supported by NSF (grant DMR-0964886) and Air Force Office of Scientific Research (grant FA9550-07-1-0484) in the Physical Biology Center for Ultrafast Science and Technology supported by Gordon and Betty Moore Foundation at Caltech. A patent application has been filed by Caltech based on the methodology presented herein.
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