Spin-Lattice Relaxation of Hyperpolarized Metronidazole in Signal Amplification by Reversible Exchange in Micro-Tesla Fields.
Spin-Lattice Relaxation of Hyperpolarized Metronidazole in Signal Amplification by Reversible Exchange in Micro-Tesla Fields.
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超极化甲硝唑在微特斯拉场中可逆交换信号放大中的自旋晶格弛豫。
DOI：
10.1021/acs.jpcc.8b00283
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Chekmenev,EduardY
中科院分区：
文献类型：
--
作者：
Shchepin,RomanV;Jaigirdar,Lamya;Chekmenev,EduardY
金属中心上的仲氢和待超极化基底的同时可逆化学交换使得自旋序从仲氢单态自发转移到基底的核自旋。当在亚微特斯拉磁场下进行时，这种通过屏蔽中的可逆交换进行NMR信号放大的技术使得能够将对准转移到异核（SABRE-SHEATH）。SABRE-SHEATH已被证明在1分钟内将广泛的生物学上感兴趣的分子的氮-15位点超极化到高极化水平（P> 20%）。在这里，我们报告了在SABRE-SHEATH超极化过程中甲硝唑-13 C2 - 15 N2的1H，13 C和15 N自旋晶格弛豫（T1）的系统研究。在微特斯拉范围内，我们发现所有的1H，13 C和15 N自旋研究共享大约相同的T1值（约。4 s的研究条件下），因为他们的塞曼能级的混合，这是与中继SABRE-SHEATH效应的模型一致。这些T1值明显低于较高磁场（即地球磁场及以上）下的T1值，在某些情况下超过3 min。此外，在1 μT以下观察到的这些相对较短的T1值限制了SABRE-SHEATH的极化建立过程，从而限制了可达到的最大15 N极化。在1 μT以下观察到的相对较短的T1值主要是由与所用极化转移催化剂的四极铱中心或二氢质子的分子间相互作用引起的，而与14 N四极中心的分子内自旋-自旋相互作用的贡献明显较小。所提出的实验结果及其分析将有利于更合理地设计SABRE-SHEATH（i）极化转移催化剂和（ii）生物医学成像和其他应用中的超极化分子探针。
Simultaneous reversible chemical exchange ofpara-hydrogen and to-be-hyperpolarized substrate on metal centers enables spontaneous transfer of spin order frompara-hydrogen singlet to nuclear spins of the substrate. When performed at a sub-micro-tesla magnetic field, this technique of NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). SABRE-SHEATH has been shown to hyperpolarize nitrogen-15 sites of a wide range of biologically interesting molecules to a high polarization level (P> 20%) in 1 min. Here, we report on a systematic study of1H,13C, and15N spin–lattice relaxation (T1) of metronidazole-13C2-15N2in the SABRE-SHEATH hyperpolarization process. In the micro-tesla range, we find that all1H,13C, and15N spins studied share approximately the sameT1values (ca. 4 s under the conditions studied) because of mixing of their Zeeman levels, which is consistent with the model of relayed SABRE-SHEATH effect. TheseT1values are significantly lower than those at a higher magnetic field (i.e. the Earth’s magnetic field and above), which exceed 3 min in some cases. Moreover, these relatively shortT1values observed below 1 μT limit the polarization build-up process of SABRE-SHEATH, thereby limiting the maximum attainable15N polarization. The relatively shortT1values observed below 1 μT are primarily caused by intermolecular interactions with quadrupolar iridium centers or dihydride protons of the employed polarization transfer catalyst, whereas intramolecular spin–spin interactions with14N quadrupolar centers have a significantly smaller contribution. The presented experimental results and their analysis will be beneficial for more rational design of SABRE-SHEATH (i) polarization transfer catalysts and (ii) hyperpolarized molecular probes in the context of biomedical imaging and other applications.
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影响因子：
15
作者：
Colell JFP;Emondts M;Logan AWJ;Shen K;Bae J;Shchepin RV;Ortiz GX Jr;Spannring P;Wang Q;Malcolmson SJ;Chekmenev EY;Feiters MC;Rutjes FPJT;Blümich B;Theis T;Warren WS
通讯作者：
Warren WS
影响因子：
3.7
作者：
Kovtunov, Kirill V.;Kidd, Bryce E.;Koptyug, Igor V.
通讯作者：
Koptyug, Igor V.
DOI：
10.1021/je00031a001
发表时间：
1983-01-01
期刊：
JOURNAL OF CHEMICAL AND ENGINEERING DATA
影响因子：
--
作者：
RADHAKRISHNAN, K;RAMACHANDRAN, PA;CHAUDHARI, RV
通讯作者：
CHAUDHARI, RV
DOI：
10.1021/je00032a009
发表时间：
1983-01-01
期刊：
JOURNAL OF CHEMICAL AND ENGINEERING DATA
影响因子：
--
作者：
HERSKOWITZ, M;WISNIAK, J;SKLADMAN, L
通讯作者：
SKLADMAN, L
影响因子：
4.3
作者：
Logan, Angus W. J.;Theis, Thomas;Malcolmson, Steven J.
通讯作者：
Malcolmson, Steven J.