Efficient NMR Signal Enhancement of Heteronuclei via Reversible Exchange at Millitesla Magnetic Fields
- 1Laboratory of Magnetic Resonance Microimaging, International Tomography Center SB RAS, 3A Institutskaya street, Novosibirsk, Russia, 630090
- 2Department of Chemistry, Molecular Therapeutics (MT) research program at Karmanos Cancer Institute (KCI
- 3Wayne State University
Abstract
Signal amplification by reversible exchange (SABRE) is a versatile hyperpolarization technique providing NMR signal enhancement by five orders of magnitude. The sensitivity gain offered by SABRE hyperpolarization of 13 C and 15 N heteronuclei in biologically relevant molecules enables various emerging in vivo applications, including metabolic profiling of cancerous tumors and cellular models. The pioneering spin physics developed for heteronuclear SABRE favors nano- and microtesla field range, which requires magnetic shielding of the Earth’s field, representing the key instrumentational and cost disadvantages of this method. Herein, we introduce a novel approach for heteronuclear SABRE, operating at static magnetic fields of tens to hundreds of millitesla, conveniently achieved in the fringe field of an NMR spectrometer or an MRI scanner and also readily accessible by low-cost purpose-built Halbach magnets. This approach, dubbed “SABRETACHE” (SABRE Transfer of Alignment to Coupled HEteronuclei), is effective if a substrate molecule contains two J -coupled chemically inequivalent heteronuclei, at least one of which is also J -coupled to a parahydrogen-derived hydride in a SABRE-active Ir complex. Theoretical description of SABRETACHE shows that polarization transfer results from a coherent spin mixing at level anti-crossings, which, for this type of spin systems, take place at millitesla fields. Experimental validation using the example of [ 15 N 3 ]nimorazole (clinically approved antibiotic) demonstrates that SABRETACHE can provide higher polarization levels than the well-established SABRE-SHEATH approach. Furthermore, SABRETACHE enabled sub-second high-resolution 15 N MRI. We envision SABRETACHE as a technically simple, robust and efficient hyperpolarization approach, which can serve as a viable alternative to the already established hyperpolarization techniques.
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BibTeX
@misc{yi2026efficient,
title = {{Efficient NMR Signal Enhancement of Heteronuclei via Reversible Exchange at Millitesla Magnetic Fields}},
author = {Anna P. Yi and Oleg G. Salnikov and Simon V. Babenko and Elizaveta S. Kononenko and Nikita V. Chukanov and Eduard Y. Chekmenev and Igor V. Koptyug},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008422/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008422/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Efficient NMR Signal Enhancement of Heteronuclei via Reversible Exchange at Millitesla Magnetic Fields
AU - Anna P. Yi
AU - Oleg G. Salnikov
AU - Simon V. Babenko
AU - Elizaveta S. Kononenko
AU - Nikita V. Chukanov
AU - Eduard Y. Chekmenev
AU - Igor V. Koptyug
PY - 2026
DA - 2026/09/07
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008422/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008422/v1
AB - Signal amplification by reversible exchange (SABRE) is a versatile hyperpolarization technique providing NMR signal enhancement by five orders of magnitude. The sensitivity gain offered by SABRE hyperpolarization of 13 C and 15 N heteronuclei in biologically relevant molecules enables various emerging in vivo applications, including metabolic profiling of cancerous tumors and cellular models. The pioneering spin physics developed for heteronuclear SABRE favors nano- and microtesla field range, which requires magnetic shielding of the Earth’s field, representing the key instrumentational and cost disadvantages of this method. Herein, we introduce a novel approach for heteronuclear SABRE, operating at static magnetic fields of tens to hundreds of millitesla, conveniently achieved in the fringe field of an NMR spectrometer or an MRI scanner and also readily accessible by low-cost purpose-built Halbach magnets. This approach, dubbed “SABRETACHE” (SABRE Transfer of Alignment to Coupled HEteronuclei), is effective if a substrate molecule contains two J -coupled chemically inequivalent heteronuclei, at least one of which is also J -coupled to a parahydrogen-derived hydride in a SABRE-active Ir complex. Theoretical description of SABRETACHE shows that polarization transfer results from a coherent spin mixing at level anti-crossings, which, for this type of spin systems, take place at millitesla fields. Experimental validation using the example of [ 15 N 3 ]nimorazole (clinically approved antibiotic) demonstrates that SABRETACHE can provide higher polarization levels than the well-established SABRE-SHEATH approach. Furthermore, SABRETACHE enabled sub-second high-resolution 15 N MRI. We envision SABRETACHE as a technically simple, robust and efficient hyperpolarization approach, which can serve as a viable alternative to the already established hyperpolarization techniques.
ER -