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Applications and Method Developments of Nuclear Magnetic Resonance (NMR) Spectroscopy and Hyperpolarized Magnetic Resonance Techniques

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Keywords
Published Papers

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Applied Chemistry".

Deadline for manuscript submissions: 31 May 2024 | Viewed by 9219

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Special Issue Editors

Dr. Nicholas Whiting

E-Mail Website
Guest Editor

Department of Physics & Astronomy and Department of Molecular & Cellular Biosciences, Rowan University, Glassboro, NJ 08028, USA
Interests: hyperpolarized magnetic resonance; silicon nanoparticles; parahydrogen; dynamic nuclear polarization, nanoparticle hyperthermia

Dr. Youngbok Lee

E-Mail Website
Guest Editor

Department of Applied Chemistry, Hanyang University, Ansan 15588, Republic of Korea
Interests: hyperpolarization; dynamic nuclear polarization; MR spectroscopy and imaging; hyperpolarized magnetic resonance imaging application

Special Issue Information

Dear Colleagues,

Nuclear magnetic resonance (NMR) spectroscopy is unmatched in terms of the ability to non-destructively interrogate molecular structures and dynamics at high levels of specificity and resolution. Unfortunately, NMR is also limited by its inherently low sensitivity that hampers the study of samples with low analyte concentrations at fast time scales. The enhancements in sensitivity, which are gained through improvements in NMR methodology, as well as hyperpolarization techniques, bolster the expanse of studies that are achievable using NMR spectroscopy and MR imaging. For example, advances in hyperpolarization methods steadily improve both the magnitude of signal enhancement as well as its applicability to a diversity of chemical samples and biological systems. Colleagues are invited to contribute original research papers or reviews to this Special Issue of Molecules, which will report on recent advances in NMR methodology as well as hyperpolarization techniques, and elucidate the means with which these gains are leveraged for improved NMR applications.

Dr. Nicholas Whiting
Dr. Youngbok Lee
Guest Editors

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Keywords

hyperpolarized magnetic resonance
parahydrogen
dynamic nuclear polarization
optical pumping
contrast agents
low field

Published Papers (5 papers)

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Research

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13 pages, 2989 KiB

Open AccessArticle

Reconversion of Parahydrogen Gas in Surfactant-Coated Glass NMR Tubes

by Robert V. Chimenti, James Daley, James Sack, Jennifer Necsutu and Nicholas Whiting

Molecules 2023, 28(5), 2329; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28052329 - 02 Mar 2023

Cited by 1 | Viewed by 1430

Abstract

The application of parahydrogen gas to enhance the magnetic resonance signals of a diversity of chemical species has increased substantially in the last decade. Parahydrogen is prepared by lowering the temperature of hydrogen gas in the presence of a catalyst; this enriches the para spin isomer beyond its normal abundance of 25% at thermal equilibrium. Indeed, parahydrogen fractions that approach unity can be attained at sufficiently low temperatures. Once enriched, the gas will revert to its normal isomeric ratio over the course of hours or days, depending on the surface chemistry of the storage container. Although parahydrogen enjoys long lifetimes when stored in aluminum cylinders, the reconversion rate is significantly faster in glass containers due to the prevalence of paramagnetic impurities that are present within the glass. This accelerated reconversion is especially relevant for nuclear magnetic resonance (NMR) applications due to the use of glass sample tubes. The work presented here investigates how the parahydrogen reconversion rate is affected by surfactant coatings on the inside surface of valved borosilicate glass NMR sample tubes. Raman spectroscopy was used to monitor changes to the ratio of the (J: 0 → 2) vs. (J: 1 → 3) transitions that are indicative of the para and ortho spin isomers, respectively. Nine different silane and siloxane-based surfactants of varying size and branching structures were examined, and most increased the parahydrogen reconversion time by 1.5×–2× compared with equivalent sample tubes that were not treated with surfactant. This includes expanding the pH₂ reconversion time from 280 min in a control sample to 625 min when the same tube is coated with (3-Glycidoxypropyl)trimethoxysilane. Full article

(This article belongs to the Special Issue Applications and Method Developments of Nuclear Magnetic Resonance (NMR) Spectroscopy and Hyperpolarized Magnetic Resonance Techniques)

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16 pages, 3363 KiB

Open AccessArticle

Hyperpolarizing DNA Nucleobases via NMR Signal Amplification by Reversible Exchange

by Bryce E. Kidd, Max E. Gemeinhardt, Jamil A. Mashni, Jonathan L. Gesiorski, Liana B. Bales, Miranda N. Limbach, Roman V. Shchepin, Kirill V. Kovtunov, Igor V. Koptyug, Eduard Y. Chekmenev and Boyd M. Goodson

Molecules 2023, 28(3), 1198; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28031198 - 25 Jan 2023

Cited by 1 | Viewed by 1627

Abstract

The present work investigates the potential for enhancing the NMR signals of DNA nucleobases by parahydrogen-based hyperpolarization. Signal amplification by reversible exchange (SABRE) and SABRE in Shield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) of selected DNA nucleobases is demonstrated with the enhancement (ε) of ¹H, ¹⁵N, and/or ¹³C spins in 3-methyladenine, cytosine, and 6-O-guanine. Solutions of the standard SABRE homogenous catalyst Ir(1,5-cyclooctadeine)(1,3-bis(2,4,6-trimethylphenyl)imidazolium)Cl (“IrIMes”) and a given nucleobase in deuterated ethanol/water solutions yielded low ¹H ε values (≤10), likely reflecting weak catalyst binding. However, we achieved natural-abundance enhancement of ¹⁵N signals for 3-methyladenine of ~3300 and ~1900 for the imidazole ring nitrogen atoms. ¹H and ¹⁵N 3-methyladenine studies revealed that methylation of adenine affords preferential binding of the imidazole ring over the pyrimidine ring. Interestingly, signal enhancements (ε~240) of both ¹⁵N atoms for doubly labelled cytosine reveal the preferential binding of specific tautomer(s), thus giving insight into the matching of polarization-transfer and tautomerization time scales. ¹³C enhancements of up to nearly 50-fold were also obtained for this cytosine isotopomer. These efforts may enable the future investigation of processes underlying cellular function and/or dysfunction, including how DNA nucleobase tautomerization influences mismatching in base-pairing. Full article

(This article belongs to the Special Issue Applications and Method Developments of Nuclear Magnetic Resonance (NMR) Spectroscopy and Hyperpolarized Magnetic Resonance Techniques)

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25 pages, 21000 KiB

Open AccessArticle

Investigating Rubidium Density and Temperature Distributions in a High-Throughput ¹²⁹Xe-Rb Spin-Exchange Optical Pumping Polarizer

by James E. Ball, Jim M. Wild and Graham Norquay

Molecules 2023, 28(1), 11; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28010011 - 20 Dec 2022

Viewed by 1700

Abstract

Accurate knowledge of the rubidium (Rb) vapor density,

[Rb]

, is necessary to correctly model the spin dynamics of

^{129}

Xe-Rb spin-exchange optical pumping (SEOP). Here we present a systematic evaluation of

[Rb]

within a high-throughput

^{129}

Xe-Rb hyperpolarizer [...] Read more.

Accurate knowledge of the rubidium (Rb) vapor density,

[Rb]

, is necessary to correctly model the spin dynamics of

^{129}

Xe-Rb spin-exchange optical pumping (SEOP). Here we present a systematic evaluation of

[Rb]

within a high-throughput

^{129}

Xe-Rb hyperpolarizer during continuous-flow SEOP. Near-infrared (

5^{2} S_{1 / 2} \to 5^{2} P_{1 / 2}

_{1}

)/5

^{2} P_{3 / 2}

_{2}

)) and violet (

5^{2} S_{1 / 2} \to 6^{2} P_{1 / 2}

^{2} P_{3 / 2}

) atomic absorption spectroscopy was used to measure

[Rb]

within 3.5 L cylindrical SEOP cells containing different spatial distributions and amounts of Rb metal. We were able to quantify deviation from the Beer-Lambert law at high optical depth for D

_{2}

and 6

^{2} P_{3 / 2}

absorption by comparison with measurements of the D

_{1}

and 6

^{2} P_{1 / 2}

absorption lines, respectively. D

_{2}

absorption deviates from the Beer-Lambert law at

{[Rb]}_{D_{2}} > 4 \times 10^{17}

^{- 3}

whilst 5

^{2}

_{1 / 2} \to 6^{2} P_{3 / 2}

absorption deviates from the Beer-Lambert law at

{[Rb]}_{6 P_{3 / 2}} > (4.16 \pm 0.01) \times 10^{19}

^{- 3}

. The measured

[Rb]

was used to estimate a

^{129}

Xe-Rb spin exchange cross section of

γ^{'} = (1.2 \pm 0.1) \times 10^{- 21}

^{3}

^{- 1}

, consistent with spin-exchange cross sections from the literature. Significant

[Rb]

heterogeneity was observed in a SEOP cell containing 1 g of Rb localized at the back of the cell. While

[Rb]

homogeneity was improved for a greater surface area of the Rb source distribution in the cell, or by using a Rb presaturator, the measured

[Rb]

was consistently lower than that predicted by saturation Rb vapor density curves. Efforts to optimize

[Rb]

and thermal management within spin polarizer systems are necessary to maximize potential future enhancements of this technology. Full article

(This article belongs to the Special Issue Applications and Method Developments of Nuclear Magnetic Resonance (NMR) Spectroscopy and Hyperpolarized Magnetic Resonance Techniques)

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11 pages, 1584 KiB

Open AccessArticle

Optical Dynamic Nuclear Polarization of ¹³C Spins in Diamond at a Low Field with Multi-Tone Microwave Irradiation

by Vladimir V. Kavtanyuk, Hyun Joon Lee, Sangwon Oh, Keunhong Jeong and Jeong Hyun Shim

Molecules 2022, 27(5), 1700; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27051700 - 04 Mar 2022

Cited by 1 | Viewed by 1906

Abstract

Majority of dynamic nuclear polarization (DNP) experiments have been requiring helium cryogenics and strong magnetic fields for a high degree of nuclear polarization. In this work, we instead demonstrate an optical hyperpolarization of naturally abundant

^{13}

C nuclei in a diamond crystal at [...] Read more.

^{13}

C nuclei in a diamond crystal at a low magnetic field and the room temperature. It exploits continuous laser irradiation for polarizing electronic spins of nitrogen vacancy centers and microwave irradiation for transferring the electronic polarization to

^{13}

C nuclear spins. We have studied the dependence of

^{13}

C polarization on laser and microwave powers. For the first time, a triplet structure corresponding to the

^{14}

N hyperfine splitting has been observed in the

^{13}

C polarization spectrum. By simultaneously exciting three microwave frequencies at the peaks of the triplet, we have achieved

^{13}

C bulk polarization of 0.113 %, leading to an enhancement of 90,000 over the thermal polarization at 17.6 mT. We believe that the multi-tone irradiation can be extended to further enhance the

^{13}

C polarization at a low magnetic field. Full article

(This article belongs to the Special Issue Applications and Method Developments of Nuclear Magnetic Resonance (NMR) Spectroscopy and Hyperpolarized Magnetic Resonance Techniques)

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Review

Jump to: Research

49 pages, 17959 KiB

Open AccessReview

Preclinical MRI Using Hyperpolarized ¹²⁹Xe

by Stephen Kadlecek, Yonni Friedlander and Rohan S. Virgincar

Molecules 2022, 27(23), 8338; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27238338 - 29 Nov 2022

Cited by 1 | Viewed by 1655

Abstract

Although critical for development of novel therapies, understanding altered lung function in disease models is challenging because the transport and diffusion of gases over short distances, on which proper function relies, is not readily visualized. In this review we summarize progress introducing hyperpolarized ¹²⁹Xe imaging as a method to follow these processes in vivo. The work is organized in sections highlighting methods to observe the gas replacement effects of breathing (Gas Dynamics during the Breathing Cycle) and gas diffusion throughout the parenchymal airspaces (3). We then describe the spectral signatures indicative of gas dissolution and uptake (4), and how these features can be used to follow the gas as it enters the tissue and capillary bed, is taken up by hemoglobin in the red blood cells (5), re-enters the gas phase prior to exhalation (6), or is carried via the vasculature to other organs and body structures (7). We conclude with a discussion of practical imaging and spectroscopy techniques that deliver quantifiable metrics despite the small size, rapid motion and decay of signal and coherence characteristic of the magnetically inhomogeneous lung in preclinical models (8). Full article

(This article belongs to the Special Issue Applications and Method Developments of Nuclear Magnetic Resonance (NMR) Spectroscopy and Hyperpolarized Magnetic Resonance Techniques)

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