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As one of the founding members of our electron microscopy development lab, I have been working on advancing biological transmission electron microscopy (TEM) technology since 1976, and have been involved in several US or worldwide “firsts”. Examples are: stereoscopic 3-D image analysis; cryo-TEM tomography of native frozen tissue; use of cryo ion-milling to prepare frozen tissue and cells for cryo-TEM; phase-plate imaging for cryo-TEM.
I currently lead two NIH-funded research projects: (1) use of cryo-focused-ion-beam (FIB) milling to prepare vitreously frozen specimens for high-resolution cryo-TEM, and (2) use of phase-plate imaging to improve contrast of vitreously frozen specimens in the cryo-TEM. These are represented in the image to the left. (A) Scanning electron microscope (SEM) image of the surface of a block of native (frozen, unstained) muscle in which cryo-FIB milling was used to thin rectangular strips for cryo-TEM imaging. (B) cryo-TEM image from a thinned area in A. This is an example of the first cryo-TEM images recorded of native, frozen muscle; however it was recorded with a conventional high-defocus method. Such a method enhances contrast but results in complete loss of certain information. (C) TEM image of a frozen liver slice recorded in-focus, which in principle does not result in complete information loss, but the image has insufficient contrast for analysis. (D) TEM image of the same specimen recorded in-focus, but using a phase plate to enhance contrast without loss of information.
I am also manager of Wadsworth Center’s 3D-EM Facility, which includes several high-end electron microscopes, including a FIB-SEM (both FIB and SEM instruments combined in a single platform) and a new custom-made 300-kV phase-plate cryo-TEM. The Facility is available for use by both Wadsworth and external investigators.