Shchepin, Roman VBarskiy, Danila ACoffey, Aaron MTheis, ThomasShi, FanWarren, Warren SGoodson, Boyd MChekmenev, Eduard Y2017-09-062017-09-062016-06-242379-3694https://hdl.handle.net/10161/15446(15)N nuclear spins of imidazole-(15)N2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A (15)N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole-(15)N2 in methanol:aqueous buffer (∼1:1). Proton binding to a (15)N site of imidazole occurs at physiological pH (pKa ∼ 7.0), and the binding event changes the (15)N 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. (15)N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.15NNMRchemical shifthyperpolarizationimidazolepH sensingparahydrogenJournal article