High Resolution 3D X-ray Diffraction Microscope

高分辨率 3D X 射线衍射显微镜

• 批准号: 6369224
• 负责人: Janos Kirz
• 金额: $ 19.92万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6369224
• 关键词: X ray crystallography; X ray microscopy; bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical automation; biomedical equipment; cell biology; cell component structure /function; charge coupled device camera; computer simulation; cryoscopy; cytology; image enhancement; imaging /visualization /scanning; liposomes; mathematics; model design /development; physical model; polystyrenes; structural biology; synchrotrons; technology /technique development; yeasts

The three dimensional imaging of a small cell by an extended form of X-ray crystallography (or equivalently the development and use of a soft X-ray diffraction microscope for use in cell biology) is proposed. This instrument is designed to provide three-dimensional images of frozen hydrated cellular and sub-cellular structures at better than 20 nm resolution. The instrument does not use optical elements to form the image instead it records the diffraction pattern of the coherently illuminated object, and using techniques borrowed from crystallography, performs the reconstruction using an iterative algorithm. This way the resolution is not limited by the optics, and future developments should improve the resolution limit further. The diffraction pattern from a non-crystalline specimen is a continuous (speckle) pattern. Unlike the case with crystals this pattern contains sufficient information to overcome the phase problem of crystallography by sampling the diffraction pattern at a finer scale. Undulator radiation at the National Synchrotron Light Source is used to provide coherent illumination of the specimen. The diffraction pattern is recorded using a CCD detector. Special care is taken to shield the detector from all but the desired information. A single pattern yields a two-dimensional image. To obtain three-dimensional reconstruction the specimen is rotated and a set of diffraction patterns is collected. Frozen hydrated specimens are used to minimize the effects of radiation damage.

提出了通过扩展形式的 X 射线晶体学（或等效地开发和使用用于细胞生物学的软 X 射线衍射显微镜）对小细胞进行三维成像。 该仪器旨在以优于 20 nm 的分辨率提供冷冻水合细胞和亚细胞结构的三维图像。 该仪器不使用光学元件形成图像，而是记录相干照明物体的衍射图案，并利用借用晶体学的技术，使用迭代算法进行重建。 这样分辨率就不会受到光学的限制，未来的发展应该会进一步提高分辨率极限。 非晶体样品的衍射图案是连续（散斑）图案。 与晶体的情况不同，该图案包含足够的信息，可以通过以更精细的尺度对衍射图案进行采样来克服晶体学的相位问题。国家同步加速器光源的波荡器辐射用于为样本提供相干照明。 使用 CCD 检测器记录衍射图案。 我们特别注意保护探测器免受除所需信息之外的所有信息的影响。 单个图案产生二维图像。为了获得三维重建，旋转样本并收集一组衍射图案。 冷冻水合样本用于最大限度地减少辐射损伤的影响。