Imaging of Biomolecular NMR Signals Amplified by Reversible Exchange with Parahydrogen Inside an MRI Scanner
Imaging of Biomolecular NMR Signals Amplified by Reversible Exchange with Parahydrogen Inside an MRI Scanner
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DOI：
10.1021/acs.jpcc.7b10549
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发表时间：
2017-11-23
影响因子：
3.7
通讯作者：
Koptyug, Igor V.
中科院分区：
文献类型：
--
作者：
Kovtunov, Kirill V.;Kidd, Bryce E.;Koptyug, Igor V.
通过可逆交换的信号放大（SABRE）技术采用与单线态仲氢的交换来有效地产生高水平的核自旋极化。自发SABRE先前已被证明是有效的毫特斯拉和微特斯拉制度。我们最近已经证明，高场SABRE也是可能的，其中能够可逆地与金属中心配位的分子的质子位点可以在高场磁体内直接超极化，从而可能提供原位超极化光谱和成像的便利性，而无需样品穿梭。在这里，我们展示了通过高场SABRE（HF-SABRE）实现的从仲氢（para-H-2）到咪唑-N-15（2）和烟酰胺-N-15的N-15原子的有效极化转移。在MRI扫描仪的高磁场下，自旋序从对位H-2质子到N-15原子的自发转移不仅允许记录原位超极化生物分子的增强的N-15 NMR光谱，而且允许使用常规MRI序列进行成像。证明了高场SABRE-hyperpolarized imidazole的2D N-15 MRI，在9.4 T磁场下空间分辨率为0.3 x 0.3 mm（2），信噪比（SNR）接近99。我们表明，原位HF-SABRE超极化生物分子的H-1 MRI（例如，咪唑-N-15（2））也是可行的。总之，这些结果表明，异质结（N-15）和H-1光谱检测和成像的高场SABRE-hyperpolarized分子是有前途的工具，为一些新兴的应用。
The signal amplification by reversible exchange (SABRE) technique employs exchange with singlet-state parahydrogen to efficiently generate high levels of nuclear spin polarization. Spontaneous SABRE has been shown previously to be efficient in the milli-Tesla and micro-Tesla regimes. We have recently demonstrated that high-field SABRE is also possible, where proton sites of molecules that are able to reversibly coordinate to a metal center can be hyperpolarized directly within high field magnets, potentially offering the convenience of in situ hyper-polarization-based spectroscopy and imaging without sample shuttling. Here, we show efficient polarization transfer from parahydrogen (para-H-2) to the N-15 atoms of imidazole-N-15(2) and nicotinamide-N-15 achieved via high-field SABRE (HF-SABRE). Spontaneous transfer of spin order from the para-H-2 protons to N-15 atoms at the high magnetic field of an MRI scanner allows one not only to record enhanced N-15 NMR spectra of in situ hyperpolarized biomolecules but also to perform imaging using conventional MRI sequences. 2D N-15 MRI of high-field SABRE-hyperpolarized imidazole with spatial resolution of 0.3 x 0.3 mm(2) at 9.4 T magnetic field and a high signal-to-noise ratio (SNR) of similar to 99 was demonstrated. We show that H-1 MRI of in situ HF-SABRE hyperpolarized biomolecules (e.g., imidazole-N-15(2)) is also feasible. Taken together, these results show that heteronuclear (N-15) and H-1 spectroscopic detection and imaging of high-field-SABRE-hyperpolarized molecules are promising tools for a number of emerging applications.