Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA 90095-1569 (USA).
Angew Chem Int Ed Engl. 2015 Feb 16;54(8):2452-6. doi: 10.1002/anie.201409027. Epub 2015 Jan 7.
Para-hydrogen-induced polarization (PHIP) is a technique capable of producing spin polarization at a magnitude far greater than state-of-the-art magnets. A significant application of PHIP is to generate contrast agents for biomedical imaging. Clinically viable and effective contrast agents not only require high levels of polarization but heterogeneous catalysts that can be used in water to eliminate the toxicity impact. Herein, we demonstrate the use of Pt nanoparticles capped with glutathione to induce heterogeneous PHIP in water. The ligand-inhibited surface diffusion on the nanoparticles resulted in a (1) H polarization of P=0.25% for hydroxyethyl propionate, a known contrast agent for magnetic resonance angiography. Transferring the (1) H polarization to a (13) C nucleus using a para-hydrogen polarizer yielded a polarization of 0.013%. The nuclear-spin polarizations achieved in these experiments are the first reported to date involving heterogeneous reactions in water.
反氢诱导极化（PHIP）是一种能够产生比现有技术磁铁大得多的自旋极化的技术。PHIP 的一个重要应用是为生物医学成像生成对比剂。临床可行且有效的对比剂不仅需要高水平的极化，还需要能够在水中使用的异相催化剂，以消除毒性影响。在此，我们展示了使用谷胱甘肽封端的 Pt 纳米粒子在水中诱导异相 PHIP。纳米粒子上配体抑制的表面扩散导致羟乙基丙酸的（1）H 极化达到 0.25%，这是一种已知的磁共振血管造影对比剂。使用反氢极化器将（1）H 极化转移到（13）C 核，得到 0.013%的极化。这些实验中实现的核自旋极化是迄今为止首次报道涉及水中异相反应的极化。
