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

描述（由申请人提供）：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组成部分。在细胞运动或细胞分泌过程中诱导的精细结构修饰通过对速冻细胞表面的扫描电子显微镜（SEM）分析以真实的时间方式捕获。类似地，在各种实验条件下在纯化的亚细胞器（晚期内体和溶酶体）中观察到的表面形态学变化可以通过SEM分析有力地可视化。细菌和真菌的表面分析可以提供它们在不同实验条件下形态变化的非常有用的信息。与通过透射电子显微镜（TEM）获得的成像不同，SEM分析能够产生具有大景深的高分辨率图像，从而产生有助于理解样品的精细表面结构的特征性三维外观。由于这个主要原因，TEM和SEM通常都应用于生物样品的超微结构形态的研究。这是一份重新提交的申请，申请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。所要求的SEM将是分析成像设施（AIF）的一部分，AIF是一种多用户成像资源，可供所有经过培训的研究者使用。目前，在该设施中安装了一台1989年安装的过时的JEOL JSM 6400 SEM，无法满足这些调查人员的需求。需要一种新的SEM在低加速电压（1-2 kV）下以高放大率（>20，000 x）成像，具有高亮度电子源，用于检测具有背散射电子的10 nm金。冷冻转移站将使水合样品成像，以避免脱水的伪影。该应用中主要用户的共同科学需求是能够在不同实验条件下从细胞、细胞器或病原体获得高分辨率表面成像。本申请中描述的低温场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;纳米制造装置;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 Currently, a much out of date JEOL JSM6400 SEM installed 1989, is present in the facility which does not fulfill the needs of these investigators.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.