Field Emission Scanning Electron Microscope for use in a multi-user Facility

描述(申请人提供)：高分辨率形态表面分析是生理和病理条件下生物学研究的一个组成部分。通过对速冻细胞表面的扫描电子显微镜(SEM)分析，实时捕捉到细胞运动或细胞分泌过程中诱导的精细结构变化。同样，在不同的实验条件下，在纯化的亚细胞细胞器(晚期内切体和溶酶体)中观察到的表面形态变化可以通过扫描电子显微镜分析得到强有力的可视化。细菌和真菌的表面分析可以提供关于它们在不同实验条件下的形态变化的非常有用的信息。与通过透射电子显微镜(TEM)获得的图像不同，扫描电子显微镜分析能够产生具有大景深的高分辨率图像，从而产生有助于了解样品精细表面结构的独特的三维外观。因此，在研究生物样品的超微结构形态时，通常应同时使用透射电子显微镜和扫描电子显微镜。这是一项重新提交的申请，用于资助最先进的高分辨率扫描电子显微镜和相关的冷冻转移系统。申请的扫描电子显微镜将是分析成像设备(AIF)的一部分，这是一个多用户成像资源，可供所有训练有素的调查人员使用。目前，安装在1989年的JEOL JSM6400扫描电子显微镜非常过时，存在于设施中，不能满足这些调查人员的需要。需要一台新的扫描电子显微镜在低加速电压(1-2千伏)下成像高倍率(&gt；20,000x)，并使用高亮度的电子源来检测10 nm金的背向散射电子。冷冻转移站将能够对水合样品进行成像，以避免脱水的伪影。在这一应用中，主要用户的共同科学需求是能够在不同的实验条件下从细胞、细胞器或病原体获得高分辨率的表面成像。本申请中描述的低温场致发射扫描电子显微镜将允许组装的主要用户分析内体生物发生和表面受体分布的精细结构方面；病原体表面形态、受体位置和元素分布；纳米碎裂装置；线虫形态；以及否则将被排除的颗粒分泌。

DESCRIPTION (provided by applicant): High resolution morphological surface analysis is an integral part of biological investigations under both physiological and pathological conditions. The fine structure modifications induced during cell motility or cellular secretion are captured in a real time manner by scanning electron microscopy (SEM) analysis of quick-frozen cell surfaces. Similarly, surface morphological changes observed in purified sub-cellular organelles (late endosomes and lysosomes) during various experimental conditions can be powerfully visualized by SEM analysis. Surface analysis of bacteria and fungi can provide very useful information on their morphological changes under differential experimental conditions. Distinct from imaging obtained by transmission electron microscopy (TEM), the SEM analysis is capable of producing high-resolution images that have great depth of field yielding a characteristic three-dimensional appearance useful for understanding the fine surface structure of a sample. For this major reason both TEM and SEM should often both be applied in the investigation of ultrastructural morphology of biological samples. This is a resubmission application for funding of a state of the art high resolution scanning electron microscope and an associated cryotransfer system. The requested SEM will be part of the Analytical Imaging Facility (AIF), a multi user imaging resource, and available to all trained investigators. Currently, a much out of date JEOL JSM6400 SEM installed 1989, is present in the facility which does not fulfill the needs of these investigators. A new SEM is required to image high magnification (>20,000x) at low accelerating voltage (1-2 kV) with a high brightness electron source for detecting 10 nm gold with backscatter electrons. A cryotransfer station will enable imaging of hydrated samples to avoid the artifacts of dehydration. The common scientific need of the major user in this application is the ability to obtain high resolution surface imaging from cells, organelles or pathogens under different experimental conditions. The cryo field emission scanning electron microscope described in this application will allow the assembled major users to analyze fine structural aspect of endosomal biogenesis and surface receptor distribution; pathogen surface morphology, receptor location and elemental distribution; nanofabricated devices; nematode morphology; and granule secretion which will be otherwise precluded.