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X射线晶体学的扩展形式对小细胞进行的三维成像（或者提出了在细胞生物学中使用的软X射线衍射显微镜的开发和使用）。 该仪器旨在提供比20 nm分辨率更好的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素来形成图像，而是记录了相干照明对象的衍射模式，并使用从晶体学借用的技术使用迭代算法进行重建。 这样，分辨率不受光学的限制，未来的发展将进一步提高分辨率限制。 来自非晶体标本的衍射图是连续的（斑点）模式。 与晶体不同，该模式包含足够的信息来克服晶体学的相位问题，通过在更细的尺度上采样衍射模式。国家同步子源处的辐射辐射用于提供标本相干照明。 使用CCD检测器记录衍射模式。 除了所需的信息之外，要格外小心地保护检测器。 单个模式产生二维图像。为了获得三维重建，旋转了试样，并收集了一组衍射模式。 冷冻水合样品用于最大程度地减少辐射损伤的影响。