15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH

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• 作者：Roman V. Shchepin ; Danila A. Barskiy ; Aaron M. Coffey ; Thomas Theis ; Fan Shi ; Warren S. Warren ; Boyd M. Goodson ; Eduard Y. Chekmenev
• 刊名：ACS Sensor
• 出版年：2016
• 出版时间：June 24, 2016
• 年：2016
• 卷：1
• 期：6
• 页码：640-644
• 全文大小：526K
• ISSN：2379-3694

文摘

¹⁵N nuclear spins of imidazole-¹⁵N₂ were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A ¹⁵N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole-¹⁵N₂ in methanol:aqueous buffer (∼1:1). Proton binding to a ¹⁵N site of imidazole occurs at physiological pH (pK_a ∼ 7.0), and the binding event changes the ¹⁵N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. ¹⁵N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.