PULSED ESR MICROSCOPE

脉冲 ESR 显微镜

• 批准号: 8363962
• 负责人: CURT R DUNNAM
• 金额: $ 6.19万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363962
• 关键词: Biological Models; Computer Systems; Development; Diffusion; Dyes; Electrons; Frequencies; Funding; Grant; Home environment; Image; Label; Magnetic Resonance Imaging; Magnetism; Measurement; Microscope; Microscopy; National Center for Research Resources; Optical Methods; Optics; Organism; Physiologic pulse; Principal Investigator; Protons; Relaxation; Research; Research Infrastructure; Resolution; Resources; Sampling; Science; Source; System; Technology; Time; United States National Institutes of Health; cost; data acquisition; imaging probe; microwave electromagnetic radiation; prototype; submicron; success; tool

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This subproject involves the development and construction of an ESR microscope operating at pulsed mode. The ESR microscope is conceptually similar to the well known Magnetic Resonance Imaging (MRI) system. The main differences are with the type of spins used for the measurements (electron vs. protons in MRI), and the image resolution (microns vs. mm). Consequently, most biologically-related samples must be doped or labelled with stable radicals to facilitate the ESR measurement (similar to dyes in optical microscopy). Furthermore, the samples must be with a typical size of no more than 1-2 mm. When combined with optical microscopy, the pulsed ESR microscope can be a valuable tool in bio-science. Spatially resolved parameters such as diffusion tensor, O2 concentration, relaxation times (T1, T2), and the ESR lineshape can reveal a wealth of information in model and live systems, inaccessible by optical methods. In the past attempts has been made to combine NMR and optical microscopy, but with limited success due to the limited resolution of NMR (~10 microns) and its high cost. The ESR microscope, which is much more sensitive, should achieve magnetic resonance images with resolution comparable to optical method (~ 1 micron), and at much lower cost (simple electromagnet vs. large superconducting magnetic in NMR microscopy).We have constructed an initial prototype of the pulsed ESR microscope. The system is made of a home-built 6-17 GHz pulsed microwave bridge, a pulsed gradient driver, a computer for system control and data acquisition, and a pulsed imaging probe (resonator+ gradient coils). Three dimensional ESR images with a resolution of 3x3x8 microns were demonstrated at 16 GHz. Further progress to higher frequencies 9up to ~60 GHz, would facilitate the required sub-micron image resolution.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 该子项目涉及开发和构建以脉冲模式运行的 ESR 显微镜。 ESR 显微镜在概念上类似于众所周知的磁共振成像 (MRI) 系统。 主要区别在于用于测量的自旋类型（MRI 中的电子与质子）以及图像分辨率（微米与毫米）。 因此，大多数生物相关样品必须掺杂或用稳定的自由基标记，以促进 ESR 测量（类似于光学显微镜中的染料）。 此外，样品的典型尺寸必须不超过1-2毫米。 当与光学显微镜相结合时，脉冲 ESR 显微镜可以成为生物科学中的宝贵工具。 空间分辨参数，例如扩散张量、O2 浓度、弛豫时间（T1、T2）和 ESR 线形，可以揭示模型和实时系统中的大量信息，这是光学方法无法获取的。 过去曾尝试将 NMR 和光学显微镜结合起来，但由于 NMR 的分辨率有限（约 10 微米）且成本高昂，因此成效有限。 ESR 显微镜的灵敏度要高得多，应该能够以与光学方法相当的分辨率（约 1 微米）实现磁共振图像，并且成本要低得多（简单电磁体与 NMR 显微镜中的大型超导磁体相比）。我们构建了一个初始的脉冲 ESR 显微镜原型。 该系统由自制的6-17 GHz脉冲微波桥、脉冲梯度驱动器、用于系统控制和数据采集的计算机以及脉冲成像探头（谐振器+梯度线圈）组成。 在 16 GHz 下演示了分辨率为 3x3x8 微米的三维 ESR 图像。 进一步发展到更高频率（9 至约 60 GHz）将有助于实现所需的亚微米图像分辨率。