Hyperpolarized Nuclear Singlet States

超极化核单线态

• 批准号: EP/I036141/1
• 负责人: Malcolm Levitt
• 金额: $ 162.91万
• 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: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FI036141%2F1
• 关键词: Hyperpolarized; Nuclear; Singlet; States

Nuclear Magnetic Resonance (NMR) is a technique which uses the fact that the nuclei of many atoms act as tinyradiotransmitters, emitting radio signals at precisely-defined frequencies, which can be detected by a carefully-tuned detector. The frequencies and strengths of the signals depend on the magnetic field in which the sample is placed: the higher field, the higher the frequency, and the stronger the signals. In an NMR experiment, the nuclei are first magnetized by placing a sample in a strong magnetic field for some time. A sequence of radiofrequency pulses is then applied to the sample, which then emits radiowaves which can be detected in the radio receiver. The pattern of emitted waves depends on what the nuclei experienced during the pulse sequence.One useful feature is that the nuclei can "remember" what happened to them some seconds before the radiosignals are emitted. This "memory" property allows one to track movements such as chemical reactions, the random displacement of molecules, and the flow of blood and other fluids by NMR. Until recently, the "memory time" of the atomic nuclei was thought to be a fixed property of the substance under study, which could not be changed significantly by the way one does the experiment. However, our group showed in 2004 that for some substances the memory time could be extended by a factor of 10 or more by using special quantum states which are non-magnetic, called singlet states.At roughly the same time, a group of researchers in Sweden, including our project partner Jan-Henrik Ardenkjaer-Larsen, developed a revolutionary method for increasing the amplitude of NMR signals by a factor of ten thousand or even more. This method is called dissolution-DNP and an instrument to implement this is built and marketed by the British company Oxford Instruments. However a drawback of the technique is that the greatly enhanced polarization (called hyperpolarization) dies out quickly. In this project we will combine these two developments by using dissolution-DNP to generate hyperpolarization and then convert the hyperpolarized substances into singlet states, which have a much longer lifetime. We will synthesize molecules which have the right properties to sustain the long-lived singlet states and perform hyperpolarized NMR imaging experiments, mapping out slow processes such as diffusion and flow. We also expect to develop methods that allow one to construct a map of the oxygen content of fluids such as blood. In this way we will develop and demonstrate a range of new magnetic resonance methods with a wide range of applications in medicine, chemical engineering and materials science.

核磁共振（NMR）是一种利用许多原子的原子核作为微小无线电发射机的技术，它以精确定义的频率发射无线电信号，这些信号可以被精心调谐的探测器探测到。信号的频率和强度取决于样品所在的磁场：磁场越高，频率越高，信号越强。在核磁共振实验中，首先将样品置于强磁场中一段时间，使原子核磁化。然后将一系列射频脉冲施加到样品上，然后样品发出可以在无线电接收器中检测到的无线电波。发射波的模式取决于原子核在脉冲序列中经历了什么。一个有用的特征是，原子核可以在无线电信号发射前几秒钟“记住”发生在它们身上的事情。这种“记忆”特性允许人们通过核磁共振追踪化学反应、分子的随机位移、血液和其他液体的流动等运动。直到最近，原子核的“记忆时间”还被认为是被研究物质的一种固定性质，不能因实验的方式而发生显著改变。然而，我们的研究小组在2004年表明，对于某些物质，通过使用特殊的非磁性量子态，即单线态，记忆时间可以延长10倍或更多。大约在同一时间，瑞典的一组研究人员，包括我们的项目合作伙伴Jan-Henrik Ardenkjaer-Larsen，开发了一种革命性的方法，可以将核磁共振信号的振幅增加一万倍甚至更多。这种方法被称为溶解- dnp，实现这种方法的仪器是由英国牛津仪器公司制造和销售的。然而，该技术的一个缺点是大大增强的极化（称为超极化）很快就会消失。在这个项目中，我们将结合这两个发展，通过使用溶解- dnp产生超极化，然后将超极化物质转化为单线态，这具有更长的寿命。我们将合成具有适当性质的分子来维持长寿命的单重态，并进行超极化核磁共振成像实验，绘制出扩散和流动等缓慢过程。我们还期望开发出一种方法，使人们能够绘制出血液等液体的含氧量图谱。通过这种方式，我们将开发和展示一系列新的磁共振方法，这些方法在医学、化学工程和材料科学方面有着广泛的应用。

项目成果

Synthesis of an isotopically labeled naphthalene derivative that supports a long-lived nuclear singlet state.

• DOI: 10.1021/acs.orglett.5b00744
• 发表时间: 2015-05-01
• 期刊: Organic letters
• 影响因子: 5.2
• 作者: Hill-Cousins JT;Pop IA;Pileio G;Stevanato G;Håkansson P;Roy SS;Levitt MH;Brown LJ;Brown RC
• 通讯作者: Brown RC

Hyperpolarized singlet lifetimes of pyruvate in human blood and in the mouse.

• DOI: 10.1002/nbm.3005
• 发表时间: 2013-12
• 期刊: NMR IN BIOMEDICINE
• 影响因子: 2.9
• 作者: Marco-Rius, Irene;Tayler, Michael C. D.;Kettunen, Mikko I.;Larkin, Timothy J.;Timm, Kerstin N.;Serrao, Eva M.;Rodrigues, Tiago B.;Pileio, Giuseppe;Ardenkjaer-Larsen, Jan Henrik;Levitt, Malcolm H.;Brindle, Kevin M.
• 通讯作者: Brindle, Kevin M.

Measurements of the persistent singlet state of N2O in blood and other solvents--potential as a magnetic tracer.

• DOI: 10.1002/mrm.23119
• 发表时间: 2011-10
• 期刊: MAGNETIC RESONANCE IN MEDICINE
• 影响因子: 3.3
• 作者: Ghosh, R. K.;Kadlecek, S. J.;Ardenkjaer-Larsen, J. H.;Pullinger, B. M.;Pileio, G.;Levitt, M. H.;Kuzma, N. N.;Rizi, R. R.
• 通讯作者: Rizi, R. R.