Compostional Imaging with Energy Filtered Scanning Transmission Electron Microscopy

使用能量过滤扫描透射电子显微镜进行成分成像

• 批准号: 9204018
• 负责人: Andrew Somlyo
• 金额: $ 43.07万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-15 至 1997-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204018&HistoricalAwards=false
• 关键词: Compostional; Imaging; Energy; Filtered; Scanning

This research group will develop methods for mapping the composition of cell membranes and organelles at 2nm-3nm resolution, with a 200kV field emission gun ıFEG!-equipped electron microscope interfaced with a parallel electron energy loss spectrometer (parallel EELS) and an X-ray detector. Physicists and biologists will collaborate to develop the special techniques required for quantitative imaging of low-concentrations of elements (e.g., Ca, P, Gd) in biological cryosections. The major obstacle to EELS, the large background due to the thickness of cryosections, will be overcome by the use of 200kV excitation and through theoretical and experimental development of optimal methods of spectral collection and data analysis. EELS spectra collected at each scanned pixel will be multiple least squares fitted with algorithms that take into account the contributions of plural plasmon scattering and, in the higher loss region, the carbon energy loss and its fine structure, and L-edges (e.g. potassium)to the EELS background. Electron optical components will be designed and added to an existing parallel EELS system to correct the gain variations that reduce detection sensitivities. High resolution compositional mapping of Ca-bound to membranes or sequestered in organelles and of phosphorylation sites will have broad biological applications and will be explored.

该研究小组将开发以2 nm-3 nm分辨率绘制细胞膜和细胞器组成图的方法，使用配备有200KV场发射枪ıFEG！的电子显微镜与并行电子能量损失光谱仪(并行EELS)和X射线探测器接口。物理学家和生物学家将合作开发对生物冷冻切片中低浓度元素(如钙、磷、锗)进行定量成像所需的特殊技术。EELS的主要障碍是由于冰冻切片厚度较大而造成的大本底，将通过使用200千伏的激励以及通过理论和实验开发最佳的光谱收集和数据分析方法来克服。在每个扫描像素处收集的EELS光谱将采用多个最小二乘算法进行拟合，该算法考虑了多个等离子激元散射的贡献，在较高损失区域，碳能量损失及其精细结构，以及L边缘(例如钾)对EELS背景的贡献。电子光学元件将被设计并添加到现有的平行鳗鱼系统中，以纠正降低探测灵敏度的增益变化。钙离子与细胞膜的结合或在细胞器中的隔离以及磷酸化位点的高分辨率成分图谱将具有广泛的生物学应用，并将被探索。