Cryo-coil MAS H/ C/ H/ N/ Probe for Highest S/N in NMR

用于 NMR 中最高信噪比的冷冻线圈 MAS H/ C/ H/ N/ 探头

• 批准号: 7108532
• 负责人: Francis DAVID Doty
• 金额: $ 54.45万
• 依托单位: DOTY SCIENTIFIC, INC.
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7108532
• 关键词: bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomarker; biomedical equipment development; cryoscience; image enhancement; image processing; magnetic field; nuclear magnetic resonance spectroscopy

DESCRIPTION (provided by applicant): For over three decades, High-Resolution (HR) Nuclear Magnetic Resonance (NMR) has been a leading analytical technique for structure and function elucidation of molecules of all types, large and small, in homogeneous systems. More recently, Magic Angle Spinning (MAS) has been combined with high-field HRNMR to extend the technique to inhomogeneous systems, such as human and animal tissues. The 1H HRMAS spectrum of malignant breast cancer tissue shows dramatically increased levels of phosphocholine compared to nonmalignant breast tissue, and it appears likely that other unambiguous markers can be identified for many other pathologies if the signal to noise ratio (SNR) of the HR-MAS probe can be increased sufficiently. MAS is also utilized by thousands of NMR researchers in fields such as macromolecule structure determination, organo-metallo-complexes, and membrane proteins. HR NMR probes for liquids have recently become available with cryogenically cooled sample coils that are revolutionizing the field of NMR owing to their factor-of-four improvement in SNR. Similar improvements in SNR may be possible in HR-MAS. The engineering challenges of developing a cryo-coil HR-MAS probe are enormous, but not insurmountable. Detailed circuit analysis, full-wave electromagnetic coil analysis, computational fluid dynamics (CFD), thermal simulations, and MAS experiments show that a combination of (1) a novel approach to quad-resonance MAS (IH/13C/2H/15N) with all of the critical circuit elements maintained near 25K, (2) integrating a ceramic dewar into a novel sample spinner system, and (3) cryogenic preamps offers the potential for a factor-of-four increase in SNR in a cryo-coil HR-MAS probe at fields at least up to 14T (600 MHz). The Phase I has demonstrated technical feasibility of a bewared MAS spinner design with a high-efficiency quad-resonance cryogenic circuit for more than an order-of-magnitude reduction in signal acquisition time. Phase II will complete the developments necessary for quad-resonance cryo-coil HR-MAS with pulsed-field gradients at fields up to 14T. Initial field-testing at the University of Georgia is expected midway through the Phase II. Subsequent work following this Phase II is expected to extend the technology to 800 MHz.

描述(由申请人提供)： 三十多年来，高分辨率核磁共振(HR)一直是均相体系中各种大小分子结构和功能研究的领先分析技术。最近，魔角旋转(MAS)与高场高分辨核磁共振相结合，将该技术扩展到非均匀系统，如人类和动物组织。恶性乳腺癌组织的1H HRMAS谱显示，与非恶性乳腺组织相比，磷胆碱水平显著增加，如果HR-MAS探针的信噪比(SNR)能够充分提高，似乎有可能在许多其他病理组织中识别其他明确的标志物。MAS还被成千上万的核磁共振研究人员用于大分子结构测定、有机金属络合物和膜蛋白等领域。 用于液体的高分辨核磁共振探头最近已经可以与低温冷却的样品线圈一起使用，由于其信噪比提高了四倍，这正在给核磁共振领域带来革命性的变化。在HR-MAS中，SNR的类似改善也是可能的。开发低温线圈HR-MAS探测器的工程挑战是巨大的，但并非不可逾越。详细的电路分析、全波电磁线圈分析、计算流体力学(CFD)、热模拟和MAS实验表明，(1)四谐振MAS(IH/13C/2H/15N)的新方法与所有关键电路元件保持在25K附近，(2)将陶瓷杜瓦集成到新型样品旋转系统中，以及(3)低温前置放大器在至少14T(600 MHz)的电场下使低温线圈HR-MAS探头的信噪比有可能提高4倍。第一阶段已经证明了已知的MAS旋转器设计的技术可行性，该设计具有高效的四谐振低温电路，可将信号采集时间减少数量级以上。第二阶段将完成四共振低温线圈HR-MAS所需的研制工作，其磁场梯度可达14T。佐治亚大学的初步现场测试预计将在第二阶段进行到一半。第二阶段之后的后续工作预计将把技术扩展到800兆赫。