HyperStore: Singlet states and supercritical fluids for storage and transport of hyperpolarised spin order

HyperStore：用于存储和传输超极化自旋顺序的单线态和超临界流体

• 批准号: EP/P005187/1
• 负责人: Giuseppe Pileio
• 金额: $ 71万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP005187%2F1
• 关键词: HyperStore; Singlet; states; supercritical; fluids

Nuclear magnetic resonance (NMR) is a versatile analytical tool with applications ranging from basic physics to medicine. In its imaging mode, MRI, it provides information on anatomy, metabolism and biological functions. However, NMR has low sensitivity, making many of its uses difficult and others impossible without some form of signal enhancement. For example, metabolic imaging of human cancer by MRI was only made possible by the recent introduction of nuclear spin hyperpolarisation methods. Among these methods, dissolution dynamic nuclear polarisation (dDNP - central to this proposal) prepare a very high degree of nuclear spin polarisation that can increase the signal-to-noise ratio up to 10,000 times. However, despite this enormous enhancement, in-vivo applications remain on the borderline of feasibility because of the relatively short lifetime of the enhanced polarisation. For example, the spatial resolution of hyperpolarised MRI images of cancer metabolism is compromised by the loss of signal during transport and purification of the hyperpolarised material. Improvements to post-hyperpolarisation protocols, allowing transport of hyperpolarised material, would therefore improve emerging techniques and open up new areas of research and applications. The proposed research will address three interconnected main obstacles: the lack of purity of the hyperpolarised material (electron radicals are required by the hyperpolarisation technique); the limited lifetime of hyperpolarised magnetisation (the presence of radicals and many other intrinsic factors make nuclear spin polarisation to decay over time, a mechanism know as spin relaxation); the limited mobility of the polarising equipment (dissolution-DNP equipment is expensive and bulky and the limited lifetime of the hyperpolarised agents makes it impossible to transport the agent for significant distances. The point-of-use is therefore confined to the near vicinity of the point-of-production).In order to overcome these obstacles we will use supercritical-CO2 chromatography to rapidly and efficiently purify the hyperpolarised material. Because spin polarisation storage times are roughly inversely proportional to viscosity, and because supercritical-CO2 has a viscosity 10-30 times lower than that of conventional solvents, we will also store the purified material under supercritical-CO2, potentially extending the length of storage time by 5-10 times. We will then explore extending storage time further by using long-lived states and by freezing the hyperpolarised solution under liquid nitrogen, freezing molecular motion and therefore minimising relaxation losses. We aim to extend storage of hyperpolarised material to over two hours, increasing distance between the point-of-production and the point-of-use. We also intend to build a convenient and portable transport device to enable transport of hyperpolarised material over long distances (as allowed by maximum lifetime achieved) with loss of no more than 50% of polarisation.

核磁共振（NMR）是一种多功能的分析工具，其应用范围从基础物理到医学。在其成像模式，MRI，它提供了解剖，代谢和生物功能的信息。然而，核磁共振的灵敏度低，使得它的许多用途都很困难，而其他用途则不可能没有某种形式的信号增强。例如，通过MRI对人类癌症的代谢成像仅通过最近引入的核自旋超极化方法才成为可能。在这些方法中，溶解动态核极化（dDNP -本提案的核心）制备了非常高程度的核自旋极化，可以将信噪比提高高达10，000倍。然而，尽管有这种巨大的增强，体内应用仍然处于可行性的边缘，因为增强的偏振的寿命相对较短。例如，癌症代谢的超极化MRI图像的空间分辨率由于超极化材料的运输和纯化期间的信号损失而受到损害。因此，对超极化后协议的改进，允许超极化材料的运输，将改善新兴技术，并开辟新的研究和应用领域。拟议中的研究将解决三个相互关联的主要障碍：超极化材料缺乏纯度（超极化技术需要电子自由基）;超极化磁化的有限寿命（自由基和许多其他内在因素的存在使核自旋极化随时间衰减，这种机制称为自旋弛豫）;极化设备（溶解-DNP设备）的有限移动性是昂贵和庞大的，并且超极化试剂的有限寿命使得不可能将试剂运输很长的距离。为了克服这些障碍，我们将使用超临界CO2色谱法来快速有效地纯化超极化材料。由于自旋极化存储时间与粘度大致成反比，并且由于超临界CO2的粘度比常规溶剂的粘度低10-30倍，因此我们还将在超临界CO2下存储纯化的材料，潜在地将存储时间延长5-10倍。然后，我们将探索通过使用长寿命状态和通过在液氮下冷冻超极化溶液，冻结分子运动，从而最大限度地减少弛豫损失来进一步延长存储时间。我们的目标是将超极化材料的存储时间延长到两个小时以上，增加生产点和使用点之间的距离。我们还打算建立一个方便和便携式的运输设备，使超极化材料的长距离运输（允许实现最大寿命），损失不超过50%的极化。

项目成果

Single-scan measurements of nuclear spin singlet order decay rates.

核自旋单重态阶衰减率的单扫描测量。

• DOI: 10.1039/d1cp00807b
• 发表时间: 2021
• 期刊: PCCP
• 作者: Melchiorre G

A pulse sequence for singlet to heteronuclear magnetization transfer: S2hM.

用于单线态到异核磁化转移的脉冲序列：S2hM。

• DOI: 10.1016/j.jmr.2017.03.002
• 发表时间: 2017
• 期刊: 1997)
• 作者: Stevanato G