Cryo-Preparation Unit for Scanning Electron Microscope

点击翻译按钮获取中文摘要

This application requests a new low-temperature (cryo-) sample preparation system for the newly-acquired (2016) high-resolution Field Emission-Scanning Electron Microscope (FE-SEM), which is located in the University of Guelph’s Advanced Analysis Centre (AAC) core facility and managed by the Office of Research. The requested cryo-preparation unit is an immediate requirement to replace the outdated and not fully-functional cryo-preparation system (2004) currently installed on the antiquated low-resolution SEM (1986) in the Department of Food Science. In an effort to maximize potential users and streamline operations to maximize efficiency, the University has moved to centralize its electron microscopy equipment in a facility that will meet the needs of all microscopists across campus, other universities and industry. The acquisition of a new cryo-preparation system will allow the Department of Food Science to decommission their old SEM and to take advantage of the greatly-improved capabilities of the new FE-SEM. Sample preparation for conventional SEM requires chemical fixation and dehydration to prepare electron-stable samples for the high vacuum environment within the electron microscope chamber. Much of the current research that uses the Food Science facility requires cryo-preparation because biological samples and food materials are high in water, which is extremely volatile when viewed under high vacuum within conventional SEM, and therefore needs to be frozen in a cryo-preparation system to view the fully hydrated structure. For biological and food samples, such as fruits, vegetables and plant tissues, dairy and meat emulsions, lipid systems, and bacteria and bacterial and fungal biofilms, a cryo- system can prepare samples in a ‘close to real’ condition. These applications suffer greatly from artifacts caused by conventional chemical fixation and drying steps. The ability to freeze the sample and immobilize the water allows for imaging after minimal sample preparation and therefore also minimal distortion. The present system has had tremendous use during its 12-year life but is now beyond its useful life as parts and service are no longer available. A new system will have improved temperature control and better vacuum for faster and more precise sample preparation. By locating the sample cryo-preparation system on the Quanta 250 FE-SEM in the AAC there will now be huge research gains to be made through the ability to image frozen samples at nanometer resolution. The research programs to be supported with this equipment include those of the applicants, 4 from Food Science and 4 from Molecular and Cellular Biology, also 4 of which hold Canada Research Chairs and one an NSERC Industrial Research Chair, as well as numerous potential users once the facility is operational.