Acquisition of an Analytical Transmission Electron Microscope and Cryo Scanning Electron Microscope

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

An analytical transmission electron microscope (TEM) and a cryotransfer system (to complement a field emission scanning electron microscope (SEM) and expand its capabilities) will be placed in the Center for Advanced Ultrastructural Research at the University of Georgia. For nearly 50 years transmission electron microscopy (TEM) has been making significant contributions to our understanding of cell structure and function, crystal structure, systematics, microbial community structure, materials analysis, and countless other fields. Today TEM plays a crucial role in biological research especially in the areas of biomolecular localization (e.g. immunogold labeling) and structural cell biology. Likewise SEM plays an essential role in the characterization of minerals and other materials. The new TEM will be equipped for the research needs of biologists and non-biologists and will serve as the primary research TEM for the University of Georgia. In order to provide the greatest benefit to the largest and most diverse number of researchers a TEM must be able to do more than take high magnification images. It must be capable of performing electron diffraction, X-ray microanalysis, and high tilt imaging for tomography and be adaptable for techniques such as cryoTEM. Similarly the cryotransfer system will complement the Center's three-year-old field emission SEM. The LEO 982 is one of the highest resolution (1.5 nm at 20KeV) SEMs on the market. Equipped with a light element EDS X-ray microanalysis system, backscatter detector, and in-lens secondary electron detector for high resolution, the Center's SEM is able to meet the research needs of many University of Georgia scientists. The cryotransfer system will allow for the examination of hydrated specimens. During conventional specimen preparation, samples must be dehydrated using organic solvents and critical point drying or freeze-drying. Highly hydrated specimens such as polysaccharide matrices, oils, and clay slurries are often significantly altered during this process. Likewise samples that are easily disturbed or are hard to preserve in their natural state (e.g. bacteria or fungal hyphae on a substrate) can be washed off during the process and thus the data acquired from the images can be significantly altered. A cryotransfer system allows one to rapidly freeze a sample and examine it directly in the SEM. While this technique is not appropriate or even necessary for many routine specimens it is often the only method by which certain specimens can be examined. The addition of cryotransfer capabilities to the LEO 982 will significantly increase the utility and versatility of this instrument and allow for many new applications that cannot presently be attempted by Georgia researchers. The Center plays an essential role in the development of graduate training and research programs for 20 different departments and more than 150 individual laboratories. In recent years, the Center's role has expanded to include confocal, quantitative fluorescence, and digital imaging and analysis, and the Center now functions as a core microscopy and imaging facility for the University. This equipment is available to researchers from the University of Georgia as well as other regional institutions and incorporated into the student-training program of the Center, which includes formal courses in microscopy, cell biology, geology, food sciences, as well as informal tours.