Simultaneous 15N polarization of several biocompatible substrates in ethanol–water mixtures by signal amplification by reversible exchange (SABRE) method

Simultaneous 15N polarization of several biocompatible substrates in ethanol–water mixtures by signal amplification by reversible exchange (SABRE) method Full article

Journal

Magnetic Resonance in Chemistry
ISSN: 0749-1581

Output data

Year: 2021, Volume: 59, Number: 12, Pages: 1216-1224 Pages count : 9 DOI: 10.1002/mrc.5184

Tags

biomolecules, parahydrogen, polarization transfer, SABRE, spin hyperpolarization

Authors

Kiryutin Alexey S. ^1,2 , Yurkovskaya Alexandra V. ^1,2 , Petrov Pavel A. ³ , Ivanov Konstantin L. ^1,2

Affiliations

1	International Tomography Center, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2	Novosibirsk State University, Novosibirsk, Russia
3	Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia

Signal amplification by reversible exchange (SABRE) is a popular method for generating strong signal enhancements in nuclear magnetic resonance (NMR). In SABRE experiments, the source of polarization is provided by the nonthermal spin order of parahydrogen (pH2, the H2 molecule in its nuclear singlet spin state). Polarization formation requires that both pH2 and a substrate molecule bind to an Ir-based complex where polarization transfer occurs. Subsequently, the complex dissociates and free polarized substrate molecules are formed. In this work, we present approaches towards biocompatible SABRE, meaning that several small biomolecules are simultaneously polarized by using the SABRE method in water–ethanol solutions at room temperature. We are able to demonstrate significant 15N-NMR signal enhancements in water–ethanol solutions for biomolecules like nicotinamide, metronidazole, adenosine-5′-monophosphate, and 4-methylimidazole and found that the first three substrates are polarized at the same level as a well-known pyridine. We show that simultaneous polarization of several molecules is indeed feasible when the reactions are carried out at an ultralow field of about 400–500 nT. The achieved enhancements are between 100-fold and 15,000-fold. The resulting 15N polarization (maximal value about 4% achieved for metronidazole and pyridine at 45°C) strongly depends on the sample temperature, pH2 bubbling pressure, and pH2 flow. One more parameter, which is important for optimizing the enhancement, is the solvent pH. Hence, this study presents a step in developing biocompatible SABRE polarization and gives a clue on how such SABRE experiments should be optimized to achieve the highest NMR signal enhancement.

Kiryutin A.S. , Yurkovskaya A.V. , Petrov P.A. , Ivanov K.L.
Simultaneous 15N polarization of several biocompatible substrates in ethanol–water mixtures by signal amplification by reversible exchange (SABRE) method
Magnetic Resonance in Chemistry. 2021. V.59. N12. P.1216-1224. DOI: 10.1002/mrc.5184 WOS OpenAlex

Published online:	Jan 4, 2021
Submitted:	Jan 14, 2021
Accepted:	Jun 1, 2021

Web of science:	WOS:000660888200001
OpenAlex:	W3165642123

DB	Citing
OpenAlex	11