Rovedo Philipp, Knecht Stephan, Bäumlisberger Tim, Cremer Anna Lena, Duckett Simon B, Mewis Ryan E, Green Gary G R, Burns Michael, Rayner Peter J, Leibfritz Dieter, Korvink Jan G, Hennig Jürgen, Pütz Gerhard, von Elverfeldt Dominik, Hövener Jan-Bernd
Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg , Breisacher Strasse 60 a, 79106 Freiburg, Germany.
Centre for Hyperpolarization in Magnetic Resonance, University of York , York, YO10 5DD, U.K.
J Phys Chem B. 2016 Jun 30;120(25):5670-7. doi: 10.1021/acs.jpcb.6b02830. Epub 2016 Jun 17.
In this work, we illustrate a method to continuously hyperpolarize a biomolecule, nicotinamide, in water using parahydrogen and signal amplification by reversible exchange (SABRE). Building on the preparation procedure described recently by Truong et al. [ J. Phys. Chem. B , 2014 , 118 , 13882 - 13889 ], aqueous solutions of nicotinamide and an Ir-IMes catalyst were prepared for low-field NMR and MRI. The (1)H-polarization was continuously renewed and monitored by NMR experiments at 5.9 mT for more than 1000 s. The polarization achieved corresponds to that induced by a 46 T magnet (P = 1.6 × 10(-4)) or an enhancement of 10(4). The polarization persisted, although reduced, if cell culture medium (DPBS with Ca(2+) and Mg(2+)) or human cells (HL-60) were added, but was no longer observable after the addition of human blood. Using a portable MRI unit, fast (1)H-MRI was enabled by cycling the magnetic field between 5 mT and the Earth's field for hyperpolarization and imaging, respectively. A model describing the underlying spin physics was developed that revealed a polarization pattern depending on both contact time and magnetic field. Furthermore, the model predicts an opposite phase of the dihydrogen and substrate signal after one exchange, which is likely to result in the cancelation of some signal at low field.
在这项工作中，我们展示了一种利用仲氢和可逆交换信号放大（SABRE）在水中连续超极化生物分子烟酰胺的方法。基于Truong等人最近描述的制备程序[《物理化学杂志B》，2014年，118卷，13882 - 13889页]，制备了用于低场核磁共振和磁共振成像的烟酰胺水溶液和Ir-IMes催化剂。通过在5.9 mT下进行核磁共振实验，（1）H极化被连续更新并监测超过1000秒。所实现的极化相当于由46 T磁体诱导的极化（P = 1.6 × 10^(-4)）或增强了10^4倍。如果添加细胞培养基（含Ca(2+)和Mg(2+)的DPBS）或人类细胞（HL-60），极化会持续存在，尽管有所降低，但添加人类血液后极化不再可观测到。使用便携式磁共振成像单元，通过分别在5 mT和地磁场之间循环磁场进行超极化和成像，实现了快速（1）H磁共振成像。开发了一个描述潜在自旋物理的模型，该模型揭示了一种取决于接触时间和磁场的极化模式。此外，该模型预测一次交换后二氢和底物信号的相位相反，这可能导致在低场下一些信号的抵消。
