1
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Eills J, Budker D, Cavagnero S, Chekmenev EY, Elliott SJ, Jannin S, Lesage A, Matysik J, Meersmann T, Prisner T, Reimer JA, Yang H, Koptyug IV. Spin Hyperpolarization in Modern Magnetic Resonance. Chem Rev 2023; 123:1417-1551. [PMID: 36701528 PMCID: PMC9951229 DOI: 10.1021/acs.chemrev.2c00534] [Citation(s) in RCA: 59] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Magnetic resonance techniques are successfully utilized in a broad range of scientific disciplines and in various practical applications, with medical magnetic resonance imaging being the most widely known example. Currently, both fundamental and applied magnetic resonance are enjoying a major boost owing to the rapidly developing field of spin hyperpolarization. Hyperpolarization techniques are able to enhance signal intensities in magnetic resonance by several orders of magnitude, and thus to largely overcome its major disadvantage of relatively low sensitivity. This provides new impetus for existing applications of magnetic resonance and opens the gates to exciting new possibilities. In this review, we provide a unified picture of the many methods and techniques that fall under the umbrella term "hyperpolarization" but are currently seldom perceived as integral parts of the same field. Specifically, before delving into the individual techniques, we provide a detailed analysis of the underlying principles of spin hyperpolarization. We attempt to uncover and classify the origins of hyperpolarization, to establish its sources and the specific mechanisms that enable the flow of polarization from a source to the target spins. We then give a more detailed analysis of individual hyperpolarization techniques: the mechanisms by which they work, fundamental and technical requirements, characteristic applications, unresolved issues, and possible future directions. We are seeing a continuous growth of activity in the field of spin hyperpolarization, and we expect the field to flourish as new and improved hyperpolarization techniques are implemented. Some key areas for development are in prolonging polarization lifetimes, making hyperpolarization techniques more generally applicable to chemical/biological systems, reducing the technical and equipment requirements, and creating more efficient excitation and detection schemes. We hope this review will facilitate the sharing of knowledge between subfields within the broad topic of hyperpolarization, to help overcome existing challenges in magnetic resonance and enable novel applications.
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Affiliation(s)
- James Eills
- Institute
for Bioengineering of Catalonia, Barcelona
Institute of Science and Technology, 08028Barcelona, Spain,
| | - Dmitry Budker
- Johannes
Gutenberg-Universität Mainz, 55128Mainz, Germany,Helmholtz-Institut,
GSI Helmholtzzentrum für Schwerionenforschung, 55128Mainz, Germany,Department
of Physics, UC Berkeley, Berkeley, California94720, United States
| | - Silvia Cavagnero
- Department
of Chemistry, University of Wisconsin, Madison, Madison, Wisconsin53706, United States
| | - Eduard Y. Chekmenev
- Department
of Chemistry, Integrative Biosciences (IBio), Karmanos Cancer Institute
(KCI), Wayne State University, Detroit, Michigan48202, United States,Russian
Academy of Sciences, Moscow119991, Russia
| | - Stuart J. Elliott
- Molecular
Sciences Research Hub, Imperial College
London, LondonW12 0BZ, United Kingdom
| | - Sami Jannin
- Centre
de RMN à Hauts Champs de Lyon, Université
de Lyon, CNRS, ENS Lyon, Université Lyon 1, 69100Villeurbanne, France
| | - Anne Lesage
- Centre
de RMN à Hauts Champs de Lyon, Université
de Lyon, CNRS, ENS Lyon, Université Lyon 1, 69100Villeurbanne, France
| | - Jörg Matysik
- Institut
für Analytische Chemie, Universität
Leipzig, Linnéstr. 3, 04103Leipzig, Germany
| | - Thomas Meersmann
- Sir
Peter Mansfield Imaging Centre, University Park, School of Medicine, University of Nottingham, NottinghamNG7 2RD, United Kingdom
| | - Thomas Prisner
- Institute
of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic
Resonance, Goethe University Frankfurt, , 60438Frankfurt
am Main, Germany
| | - Jeffrey A. Reimer
- Department
of Chemical and Biomolecular Engineering, UC Berkeley, and Materials Science Division, Lawrence Berkeley National
Laboratory, Berkeley, California94720, United States
| | - Hanming Yang
- Department
of Chemistry, University of Wisconsin, Madison, Madison, Wisconsin53706, United States
| | - Igor V. Koptyug
- International Tomography Center, Siberian
Branch of the Russian Academy
of Sciences, 630090Novosibirsk, Russia,
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2
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Lee G, Kageyama Y, Takeda S. Site-Selective Spin-Probe with a Photocleavable Macrocyclic Linker for Measuring the Dynamics of Water Surrounding a Liposomal Assembly. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Gyeorye Lee
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Yoshiyuki Kageyama
- Faculty of Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Sadamu Takeda
- Faculty of Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
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3
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Cheney DJ, Wedge CJ. Sample volume effects in optical overhauser dynamic nuclear polarization. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 337:107170. [PMID: 35240365 DOI: 10.1016/j.jmr.2022.107170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/13/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
The optical dynamic nuclear polarization (DNP) method has been proposed as an alternative to microwave pumping as a hyperpolarization method for solution-state NMR studies. Using continuous laser illumination to photogenerate triplet states in the presence of a persistent radical produces chemically-induced dynamic electron polarization (CIDEP) via the radical-triplet pair mechanism (RTPM), with cross-relaxation transferring this to nuclear hyperpolarization via an Overhauser mechanism. Numerical simulations have previously indicated that reducing the sample volume while maintaining a constant optical density can significantly increase the NMR signal enhancement, due to the larger steady-state concentration of triplets obtained. Here we provide the first experimental confirmation of these effects, producing a nearly five-fold increase in the optical DNP enhancement factor just by reducing the sample volume with optimal dye and radical concentrations adjusted for each optical path length. The results are supported with an in depth analysis of volume effects in the numerical model, with which they are in good qualitative agreement. These important observations will impact on the future development of the technique, with particular significance for attempts to apply DNP methods to increase sensitivity for volume-limited biological samples.
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Affiliation(s)
- Daniel J Cheney
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom
| | - Christopher J Wedge
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
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4
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Levien M, Reinhard M, Hiller M, Tkach I, Bennati M, Orlando T. Spin density localization and accessibility of organic radicals affect liquid-state DNP efficiency. Phys Chem Chem Phys 2021; 23:4480-4485. [PMID: 33599637 DOI: 10.1039/d0cp05796g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report a large variation in liquid DNP performance of up to a factor of about five in coupling factor among organic radicals commonly used as polarizing agents. A comparative study of 1H and 13C DNP in model systems shows the impact of the spin density distribution and accessibility of the radical site by the target molecule.
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Affiliation(s)
- Marcel Levien
- ESR Spectroscopy Group, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, Göttigen, Germany.
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5
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Dale MW, Cheney DJ, Vallotto C, Wedge CJ. Viscosity effects on optically generated electron and nuclear spin hyperpolarization. Phys Chem Chem Phys 2020; 22:28173-28182. [PMID: 33291127 DOI: 10.1039/d0cp04012f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Spin hyperpolarization can dramatically increase signal intensities in magnetic resonance experiments, providing either improved bulk sensitivity or additional spectroscopic detail through selective enhancements. While typical hyperpolarization approaches have utilized microwave irradiation, one emerging route is the use of optically generated triplet states. We report an investigation into the effects of solution viscosity on radical-triplet pair interactions, propose a new standard for quantification of the hyperpolarization in EPR experiments, and demonstrate a significant increase in the optically generated 1H NMR signal enhancement upon addition of glycerol to aqueous solutions.
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Affiliation(s)
- Matthew W Dale
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
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6
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Cheney DJ, Wedge CJ. Optically-generated Overhauser dynamic nuclear polarization: A numerical analysis. J Chem Phys 2020; 152:034202. [DOI: 10.1063/1.5133408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel J. Cheney
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
| | - Christopher J. Wedge
- Department of Chemical Sciences, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
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7
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Parigi G, Ravera E, Bennati M, Luchinat C. Understanding Overhauser Dynamic Nuclear Polarisation through NMR relaxometry. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1527409] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Giacomo Parigi
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Italy
| | - Enrico Ravera
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Italy
| | - Marina Bennati
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Department of Chemistry, Georg-Augusta-University, Göttingen, Germany
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Schiff”, University of Florence, Sesto Fiorentino, Italy
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8
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Biller JR, Stupic KF, Moreland J. A table-top PXI based low-field spectrometer for solution dynamic nuclear polarization. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:153-163. [PMID: 29049871 DOI: 10.1002/mrc.4672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/29/2017] [Accepted: 10/04/2017] [Indexed: 06/07/2023]
Abstract
We present the development of a portable dynamic nuclear polarization (DNP) instrument based on the PCI eXtensions for Instrumentation platform. The main purpose of the instrument is for study of 1 H polarization enhancements in solution through the Overhauser mechanism at low magnetic fields. A DNP probe set was constructed for use at 6.7 mT, using a modified Alderman-Grant resonator at 241 MHz for saturation of the electron transition. The solenoid for detection of the enhanced 1 H signal at 288 kHz was constructed with Litz wire. The largest observed 1 H enhancements (ε) at 6.7 mT for 14 N-CTPO radical in air saturated aqueous solution was ε~65. A concentration dependence of the enhancement is observed, with maximum ε at 5.5 mM. A low resonator efficiency for saturation of the electron paramagnetic resonance transition results in a decrease in ε for the 10.3 mM sample. At high incident powers (42 W) and long pump times, capacitor heating effects can also decrease the enhancement. The core unit and program described here could be easily adopted for multi-frequency DNP work, depending on available main magnets and selection of the "plug and play" arbitrary waveform generator, digitizer, and radiofrequency synthesizer PCI eXtensions for Instrumentatione cards.
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Affiliation(s)
- Joshua R Biller
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO, USA
| | - Karl F Stupic
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO, USA
| | - J Moreland
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO, USA
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9
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Biller JR, Barnes R, Han S. Perspective of Overhauser dynamic nuclear polarization for the study of soft materials. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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10
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One-thousand-fold enhancement of high field liquid nuclear magnetic resonance signals at room temperature. Nat Chem 2017. [DOI: 10.1038/nchem.2723] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Neudert O, Mattea C, Stapf S. A compact X-Band resonator for DNP-enhanced Fast-Field-Cycling NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 271:7-14. [PMID: 27526396 DOI: 10.1016/j.jmr.2016.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 08/05/2016] [Accepted: 08/06/2016] [Indexed: 06/06/2023]
Abstract
A new probehead was developed enabling Dynamic Nuclear Polarization (DNP)-enhanced Fast-Field-Cycling relaxometry at 340mT polarization field strength. It is based on a dielectric cavity resonator operating in the TM110 mode at 9.5GHz, which is suitable for both transverse and axial magnet geometries with a bore access of at least 20mm. The probehead includes a planar radio frequency coil for NMR detection and is compatible with standard 3mm NMR tubes. The resonator was assessed in terms of the microwave conversion factor and microwave-induced sample heating effects. Due to the compact size of the cavity, appreciable microwave magnetic field strengths were observed even with only moderate quality factors. Exemplary DNP experiments at 9.5GHz and 2.0GHz microwave frequency are compared for three different viscous samples, demonstrating the advantage of DNP at 9.5GHz for such systems. This new probehead enables new applications of DNP-enhanced Fast-Field-Cycling relaxometry of viscous and solid systems.
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Affiliation(s)
- Oliver Neudert
- Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany.
| | - Carlos Mattea
- Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany
| | - Siegfried Stapf
- Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany
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12
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van Meerten SGJ, Tayler MCD, Kentgens APM, van Bentum PJM. Towards Overhauser DNP in supercritical CO(2). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 267:30-6. [PMID: 27082277 DOI: 10.1016/j.jmr.2016.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/01/2016] [Accepted: 04/03/2016] [Indexed: 05/14/2023]
Abstract
Overhauser Dynamic Nuclear Polarization (ODNP) is a well known technique to improve NMR sensitivity in the liquid state, where the large polarization of an electron spin is transferred to a nucleus of interest by cross-relaxation. The efficiency of the Overhauser mechanism for dipolar interactions depends critically on fast local translational dynamics at the timescale of the inverse electron Larmor frequency. The maximum polarization enhancement that can be achieved for (1)H at high magnetic fields benefits from a low viscosity solvent. In this paper we investigate the option to use supercritical CO2 as a solvent for Overhauser DNP. We have investigated the diffusion constants and longitudinal nuclear relaxation rates of toluene in high pressure CO2. The change in (1)H T1 by addition of TEMPO radical was analyzed to determine the Overhauser cross-relaxation in such a mixture, and is compared with calculations based on the Force Free Hard Sphere (FFHS) model. By analyzing the relaxation data within this model we find translational correlation times in the range of 2-4ps, depending on temperature, pressure and toluene concentration. Such short correlation times may be instrumental for future Overhauser DNP applications at high magnetic fields, as are commonly used in NMR. Preliminary DNP experiments have been performed at 3.4T on high pressure superheated water and model systems such as toluene in high pressure CO2.
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Affiliation(s)
- S G J van Meerten
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| | - M C D Tayler
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| | - A P M Kentgens
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| | - P J M van Bentum
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands.
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13
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Simultaneous acquisition of multi-nuclei enhanced NMR/MRI by solution-state dynamic nuclear polarization. Sci China Chem 2016. [DOI: 10.1007/s11426-015-0512-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Ravera E, Luchinat C, Parigi G. Basic facts and perspectives of Overhauser DNP NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:78-87. [PMID: 26920833 DOI: 10.1016/j.jmr.2015.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 05/03/2023]
Abstract
After the first surprisingly large (1)H DNP enhancements of the water signal in aqueous solutions of nitroxide radicals observed at high magnetic fields, Overhauser DNP is gaining increasing attention for a number of applications now flourishing, showing the potentialities of this mechanism in solution and solid state NMR as well as in MRI. Unexpected Overhauser DNP enhancements in insulating solids were recently measured at 100K, with a magnitude which increases with the applied magnetic field. We recapitulate here the theoretical premises of Overhauser DNP in solution and analyze the effects of the various parameters on the efficacy of the mechanism, underlining the link between the DNP enhancements and the field dependent relaxation properties. Promisingly, more effective DNP enhancements are expected by exploiting the potentialities offered by (13)C detection and the use of supercritical fluids.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy.
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15
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van Bentum J, van Meerten B, Sharma M, Kentgens A. Perspectives on DNP-enhanced NMR spectroscopy in solutions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:59-67. [PMID: 26920831 DOI: 10.1016/j.jmr.2016.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 05/03/2023]
Abstract
More than 60 years after the seminal work of Albert Overhauser on dynamic nuclear polarization by dynamic cross relaxation of coupled electron-nuclear spin systems, the quest for sensitivity enhancement in NMR spectroscopy is as pressing as ever. In this contribution we will review the status and perspectives for dynamic nuclear polarization in the liquid state. An appealing approach seems to be the use of supercritical solvents that may allow an extension of the Overhauser mechanism towards common high magnetic fields. A complementary approach is the use of solid state DNP on frozen solutions, followed by a rapid dissolution or in-situ melting step and NMR detection with substantially enhanced polarization levels in the liquid state. We will review recent developments in the field and discuss perspectives for the near future.
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16
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Küçük SE, Sezer D. Multiscale computational modeling of 13C DNP in liquids. Phys Chem Chem Phys 2016; 18:9353-7. [DOI: 10.1039/c6cp01028h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantitative prediction of 13C DNP coupling factors is achieved for acetone in water and pure chloroform.
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Affiliation(s)
- Sami Emre Küçük
- Faculty of Engineering and Natural Sciences
- Sabancı University
- 34956 Istanbul
- Turkey
| | - Deniz Sezer
- Faculty of Engineering and Natural Sciences
- Sabancı University
- 34956 Istanbul
- Turkey
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17
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Wang X, Isley Iii WC, Salido SI, Sun Z, Song L, Tsai KH, Cramer CJ, Dorn HC. Optimization and prediction of the electron-nuclear dipolar and scalar interaction in 1H and 13C liquid state dynamic nuclear polarization. Chem Sci 2015; 6:6482-6495. [PMID: 30090267 PMCID: PMC6054052 DOI: 10.1039/c5sc02499d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 07/25/2015] [Indexed: 12/19/2022] Open
Abstract
During the last 10-15 years, dynamic nuclear polarization (DNP) has evolved as a powerful tool for hyperpolarization of NMR and MRI nuclides. However, it is not as well appreciated that solution-state dynamic nuclear polarization is a powerful approach to study intermolecular interactions in solution. For solutions and fluids, the 1H nuclide is usually dominated by an Overhauser dipolar enhancement and can be significantly increased by decreasing the correlation time (τc) of the substrate/nitroxide interaction by utilizing supercritical fluids (SF CO2). For molecules containing the ubiquitous 13C nuclide, the Overhauser enhancement is usually a profile of both scalar and dipolar interactions. For carbon atoms without an attached hydrogen, a dipolar enhancement usually dominates as we illustrate for sp2 hybridized carbons in the fullerenes, C60 and C70. However, the scalar interaction is dependent on a Fermi contact interaction which does not have the magnetic field dependence inherent in the dipolar interaction. For a comprehensive range of molecular systems we show that molecules that exhibit weakly acidic complexation interaction(s) with nitroxides provide corresponding large scalar enhancements. For the first time, we report that sp hybridized (H-C) alkyne systems, for example, the phenylacetylene-nitroxide system exhibit very large scalar dominated enhancements. Finally, we demonstrate for a wide range of molecular systems that the Fermi contact interaction can be computationally predicted via electron-nuclear hyperfine coupling and correlated with experimental 13C DNP enhancements.
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Affiliation(s)
- X Wang
- Department of Chemistry , Virginia Tech , Blacksburg , Virginia 24061 , USA .
| | - W C Isley Iii
- Department of Chemistry and Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455-0431 , USA .
| | - S I Salido
- Department of Chemistry , Virginia Tech , Blacksburg , Virginia 24061 , USA .
| | - Z Sun
- Department of Chemistry , Virginia Tech , Blacksburg , Virginia 24061 , USA .
| | - L Song
- Department of Chemistry , Virginia Tech , Blacksburg , Virginia 24061 , USA .
| | - K H Tsai
- Department of Chemistry , Virginia Tech , Blacksburg , Virginia 24061 , USA .
| | - C J Cramer
- Department of Chemistry and Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455-0431 , USA .
| | - H C Dorn
- Department of Chemistry , Virginia Tech , Blacksburg , Virginia 24061 , USA .
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18
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Ardenkjaer-Larsen JH, Boebinger GS, Comment A, Duckett S, Edison AS, Engelke F, Griesinger C, Griffin RG, Hilty C, Maeda H, Parigi G, Prisner T, Ravera E, van Bentum J, Vega S, Webb A, Luchinat C, Schwalbe H, Frydman L. Facing and Overcoming Sensitivity Challenges in Biomolecular NMR Spectroscopy. Angew Chem Int Ed Engl 2015; 54:9162-85. [PMID: 26136394 PMCID: PMC4943876 DOI: 10.1002/anie.201410653] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 01/26/2015] [Indexed: 11/07/2022]
Abstract
In the Spring of 2013, NMR spectroscopists convened at the Weizmann Institute in Israel to brainstorm on approaches to improve the sensitivity of NMR experiments, particularly when applied in biomolecular settings. This multi-author interdisciplinary Review presents a state-of-the-art description of the primary approaches that were considered. Topics discussed included the future of ultrahigh-field NMR systems, emerging NMR detection technologies, new approaches to nuclear hyperpolarization, and progress in sample preparation. All of these are orthogonal efforts, whose gains could multiply and thereby enhance the sensitivity of solid- and liquid-state experiments. While substantial advances have been made in all these areas, numerous challenges remain in the quest of endowing NMR spectroscopy with the sensitivity that has characterized forms of spectroscopies based on electrical or optical measurements. These challenges, and the ways by which scientists and engineers are striving to solve them, are also addressed.
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Affiliation(s)
- Jan-Henrik Ardenkjaer-Larsen
- GE Healthcare, Broendby, Denmark; Department of Electrical Engineering, Technical University of Denmark, Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre (Denmark)
| | - Gregory S Boebinger
- U.S. National High Magnetic Field Lab, Florida State University, Tallahassee, FL 32310 (USA)
| | - Arnaud Comment
- Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, Lausanne (Switzerland)
| | - Simon Duckett
- Department of Chemistry, University of York, Heslington, York, YO10 5DD (UK)
| | - Arthur S Edison
- Department of Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32610 (USA)
| | | | | | - Robert G Griffin
- Department of Chemistry and Francis Bitter Magnet Lab, MIT, Cambridge, MA 02139-4703 (USA)
| | - Christian Hilty
- Department of Chemistry, Texas A&M University, College Station (USA)
| | - Hidaeki Maeda
- Riken Center for Life Science Technologies, Yokohama, Kanagawa (Japan)
| | - Giacomo Parigi
- CERM and Department of Chemistry, University of Florence, Sesto Fiorentino (Italy)
| | - Thomas Prisner
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main (Germany)
| | - Enrico Ravera
- CERM and Department of Chemistry, University of Florence, Sesto Fiorentino (Italy)
| | | | - Shimon Vega
- Chemical Physics Department, Weizmann Institute of Science, Rehovot (Israel)
| | - Andrew Webb
- Department of Radiology, C. J. Gorter Center for High Field MRI, Leiden University Medical Center (The Netherlands)
| | - Claudio Luchinat
- CERM and Department of Chemistry, University of Florence, Sesto Fiorentino (Italy).
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main (Germany).
| | - Lucio Frydman
- Chemical Physics Department, Weizmann Institute of Science, Rehovot (Israel).
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He Y, Feng J, Zhang Z, Wang C, Wang D, Chen F, Liu M, Liu C. A peripheral component interconnect express-based scalable and highly integrated pulsed spectrometer for solution state dynamic nuclear polarization. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:083101. [PMID: 26329168 DOI: 10.1063/1.4927453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
High sensitivity, high data rates, fast pulses, and accurate synchronization all represent challenges for modern nuclear magnetic resonance spectrometers, which make any expansion or adaptation of these devices to new techniques and experiments difficult. Here, we present a Peripheral Component Interconnect Express (PCIe)-based highly integrated distributed digital architecture pulsed spectrometer that is implemented with electron and nucleus double resonances and is scalable specifically for broad dynamic nuclear polarization (DNP) enhancement applications, including DNP-magnetic resonance spectroscopy/imaging (DNP-MRS/MRI). The distributed modularized architecture can implement more transceiver channels flexibly to meet a variety of MRS/MRI instrumentation needs. The proposed PCIe bus with high data rates can significantly improve data transmission efficiency and communication reliability and allow precise control of pulse sequences. An external high speed double data rate memory chip is used to store acquired data and pulse sequence elements, which greatly accelerates the execution of the pulse sequence, reduces the TR (time of repetition) interval, and improves the accuracy of TR in imaging sequences. Using clock phase-shift technology, we can produce digital pulses accurately with high timing resolution of 1 ns and narrow widths of 4 ns to control the microwave pulses required by pulsed DNP and ensure overall system synchronization. The proposed spectrometer is proved to be both feasible and reliable by observation of a maximum signal enhancement factor of approximately -170 for (1)H, and a high quality water image was successfully obtained by DNP-enhanced spin-echo (1)H MRI at 0.35 T.
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Affiliation(s)
- Yugui He
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jiwen Feng
- State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhi Zhang
- State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Chao Wang
- State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Dong Wang
- State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Fang Chen
- State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Maili Liu
- State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Chaoyang Liu
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
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20
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Ardenkjaer-Larsen JH, Boebinger GS, Comment A, Duckett S, Edison AS, Engelke F, Griesinger C, Griffin RG, Hilty C, Maeda H, Parigi G, Prisner T, Ravera E, van Bentum J, Vega S, Webb A, Luchinat C, Schwalbe H, Frydman L. Neue Ansätze zur Empfindlichkeitssteigerung in der biomolekularen NMR-Spektroskopie. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410653] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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21
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Küçük SE, Neugebauer P, Prisner TF, Sezer D. Molecular simulations for dynamic nuclear polarization in liquids: a case study of TEMPOL in acetone and DMSO. Phys Chem Chem Phys 2015; 17:6618-28. [PMID: 25665728 DOI: 10.1039/c4cp05832a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A computational strategy for calibrating, validating and analyzing molecular dynamics (MD) simulations to predict dynamic nuclear polarization (DNP) coupling factors and relaxivities of proton spins is presented. Simulations of the polarizing agent TEMPOL in liquid acetone and DMSO are conducted at low (infinite dilution) and high (1 M) concentrations of the free radical. Because DNP coupling factors and relaxivities are sensitive to the time scales of the molecular motions, the MD simulations are calibrated to reproduce the bulk translational diffusion coefficients of the pure solvents. The simulations are then validated by comparing with experimental dielectric relaxation spectra, which report on the rotational dynamics of the molecular electric dipole moments. The analysis consists of calculating spectral density functions (SDFs) of the magnetic dipole-dipole interaction between the electron spin of TEMPOL and nuclear spins of the solvent protons. Here, MD simulations are used in combination with an analytically tractable model of molecular motion. While the former provide detailed information at relatively short spin-spin distances, the latter includes contributions at large separations, all the way to infinity. The relaxivities calculated from the SDFs of acetone and DMSO are in excellent agreement with experiments at 9.2 T. For DMSO we calculate a coupling factor in agreement with experiment while for acetone we predict a value that is larger by almost 50%, suggesting a possibility for experimental improvement.
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Affiliation(s)
- Sami Emre Küçük
- Faculty of Engineering and Natural Sciences, Sabancı University, Orhanlı-Tuzla, 34956 Istanbul, Turkey.
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22
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Ganssle PJ, Shin HD, Seltzer SJ, Bajaj VS, Ledbetter MP, Budker D, Knappe S, Kitching J, Pines A. Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Ganssle PJ, Shin HD, Seltzer SJ, Bajaj VS, Ledbetter MP, Budker D, Knappe S, Kitching J, Pines A. Ultra-low-field NMR relaxation and diffusion measurements using an optical magnetometer. Angew Chem Int Ed Engl 2014; 53:9766-70. [PMID: 25081416 DOI: 10.1002/anie.201403416] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 11/11/2022]
Abstract
Nuclear magnetic resonance (NMR) relaxometry and diffusometry are important tools for the characterization of heterogeneous materials and porous media, with applications including medical imaging, food characterization and oil-well logging. These methods can be extremely effective in applications where high-resolution NMR is either unnecessary, impractical, or both, as is the case in the emerging field of portable chemical characterization. Here, we present a proof-of-concept experiment demonstrating the use of high-sensitivity optical magnetometers as detectors for ultra-low-field NMR relaxation and diffusion measurements.
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Affiliation(s)
- Paul J Ganssle
- Department of Chemistry, University of California, Berkeley, CA 94720 (USA); Material Science Division, Lawrence Berkeley National Labs, Berkeley, CA 94720 (USA).
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24
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van der Heijden GHA, Kentgens APM, van Bentum PJM. Liquid state dynamic nuclear polarization of ethanol at 3.4 T (95 GHz). Phys Chem Chem Phys 2014; 16:8493-502. [PMID: 24668422 DOI: 10.1039/c3cp55254c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamic Nuclear Polarization (DNP) in the liquid state has become the focus of attention to improve the NMR sensitivity of mass limited samples. The Overhauser model predicts a fast reduction in DNP enhancement at high magnetic fields where the electron Larmor frequency exceeds the typical inverse correlation time of the magnetic interaction between an unpaired electron spin of a radical and proton spins of the solvent molecules. The Overhauser hard sphere model is able to predict quantitatively the DNP enhancement for water TEMPOL solutions. The increase in temperature due to dielectric heating of the sample acts to reduce the correlation times and allows a substantial Overhauser DNP. In this paper we extend the work done on water towards other small molecules, such as ethanol. Experimentally we observe a similar enhancement for all three proton groups in the ethanol molecule. The classical interpretation of the low field Overhauser experiments on ethanol invokes a very fast anisotropic rotation of the hydrogen bonded TEMPOL-ethanol complex to explain the fast relaxation of the OH proton. Here we will discuss W-band relaxation and DNP enhancement within this classical model. Although the description can be made quantitative, the invoked parameters do not seem to be realistic. We will propose an alternative model based on the dynamic interaction both in free collision and due to modulation of the hydrogen bond length of the complex.
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Affiliation(s)
- G H A van der Heijden
- Institute for Molecules and Materials, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands.
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25
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Neudert O, Raich HP, Mattea C, Stapf S, Münnemann K. An Alderman-Grant resonator for S-Band Dynamic Nuclear Polarization. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 242:79-85. [PMID: 24607825 DOI: 10.1016/j.jmr.2014.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/31/2014] [Accepted: 02/01/2014] [Indexed: 06/03/2023]
Abstract
An Alderman-Grant resonator with resonance at 2GHz (S-Band) was simulated, developed and constructed for Dynamic Nuclear Polarization (DNP) experiments at 73mT. The resonator fits into magnet bores with a minimum diameter of 20mm and is compatible with standard 3mm NMR tubes. The compact resonator design achieves good separation of electric and magnetic fields and therefore can be used with comparatively large sample volumes with only small sample heating effects comparable to those obtained with optimized X- and W-Band DNP setups. The saturation efficiency and sample heating effects were investigated for Overhauser DNP experiments of aqueous solutions of TEMPOL radical, showing relative saturation better than 0.9 and sample heating not exceeding a few Kelvin even at high microwave power and long irradiation time. An application is demonstrated, combining the DNP setup with a commercial fast field cycling NMR relaxometer. Using this resonator design at low microwave frequencies can provide DNP polarization for a class of low-field and time-domain NMR experiments and therefore may enable new applications that benefit from increased sensitivity.
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Affiliation(s)
- Oliver Neudert
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
| | - Hans-Peter Raich
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
| | - Carlos Mattea
- Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany.
| | - Siegfried Stapf
- Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany.
| | - Kerstin Münnemann
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
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26
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Sezer D. Rationalizing Overhauser DNP of nitroxide radicals in water through MD simulations. Phys Chem Chem Phys 2014; 16:1022-32. [DOI: 10.1039/c3cp53565g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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27
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Franck JM, Pavlova A, Scott JA, Han S. Quantitative cw Overhauser effect dynamic nuclear polarization for the analysis of local water dynamics. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 74:33-56. [PMID: 24083461 PMCID: PMC3798041 DOI: 10.1016/j.pnmrs.2013.06.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 01/10/2013] [Indexed: 05/03/2023]
Abstract
Liquid state Overhauser effect Dynamic Nuclear Polarization (ODNP) has experienced a recent resurgence of interest. The ODNP technique described here relies on the double resonance of electron spin resonance (ESR) at the most common, i.e. X-band (∼10GHz), frequency and ¹H nuclear magnetic resonance (NMR) at ∼15 MHz. It requires only a standard continuous wave (cw) ESR spectrometer with an NMR probe inserted or built into an X-band cavity. We focus on reviewing a new and powerful manifestation of ODNP as a high frequency NMR relaxometry tool that probes dipolar cross relaxation between the electron spins and the ¹H nuclear spins at X-band frequencies. This technique selectively measures the translational mobility of water within a volume extending 0.5-1.5 nm outward from a nitroxide radical spin probe that is attached to a targeted site of a macromolecule. It allows one to study the dynamics of water that hydrates or permeates the surface or interior of proteins, polymers, and lipid membrane vesicles. We begin by reviewing the recent advances that have helped develop ODNP into a tool for mapping the dynamic landscape of hydration water with sub-nanometer locality. In order to bind this work coherently together and to place it in the context of the extensive body of research in the field of NMR relaxometry, we then rephrase the analytical model and extend the description of the ODNP-derived NMR signal enhancements. This extended model highlights several aspects of ODNP data analysis, including the importance of considering all possible effects of microwave sample heating, the need to consider the error associated with various relaxation rates, and the unique ability of ODNP to probe the electron-¹H cross-relaxation process, which is uniquely sensitive to fast (tens of ps) dynamical processes. By implementing the relevant corrections in a stepwise fashion, this paper draws a consensus result from previous ODNP procedures and then shows how such data can be further corrected to yield clear and reproducible saturation of the NMR hyperpolarization process. Finally, drawing on these results, we broadly survey the previous ODNP dynamics literature. We find that the vast number of published, empirical hydration dynamics data can be reproducibly classified into regimes of surface, interfacial, vs. buried water dynamics.
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Affiliation(s)
- John M Franck
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
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28
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Neugebauer P, Krummenacker JG, Denysenkov VP, Parigi G, Luchinat C, Prisner TF. Liquid state DNP of water at 9.2 T: an experimental access to saturation. Phys Chem Chem Phys 2013; 15:6049-56. [PMID: 23493879 DOI: 10.1039/c3cp44461a] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have performed liquid state ("Overhauser") Dynamic Nuclear Polarization (DNP) experiments at high magnetic field (9.2 T, corresponding to 260 GHz EPR and 400 MHz (1)H-NMR resonance frequency) on aqueous solutions of (14)N-TEMPOL nitroxide radicals. Integrated signal enhancements exceeding -80 were observed for the water protons at microwave superheated temperatures (160 °C) and still -14 at ambient temperatures (45 °C) relevant to biological applications. Different contributions contributing to the DNP enhancement such as saturation factor, leakage factor and sample temperature under microwave irradiation could be determined independently for a high spin concentration of 1 M, allowing the calculation of the coupling factors as a function of temperature and a quantitative comparison of this parameter with values derived from field dependent relaxation measurements or predictions from MD simulation.
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Affiliation(s)
- Petr Neugebauer
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe-University, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany
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29
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Sezer D. Computation of DNP coupling factors of a nitroxide radical in toluene: seamless combination of MD simulations and analytical calculations. Phys Chem Chem Phys 2013; 15:526-40. [DOI: 10.1039/c2cp42430d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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30
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Türke MT, Bennati M. Comparison of Overhauser DNP at 0.34 and 3.4 T with Frémy's Salt. APPLIED MAGNETIC RESONANCE 2012; 43:129-138. [PMID: 22815593 PMCID: PMC3396338 DOI: 10.1007/s00723-012-0362-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 05/11/2012] [Indexed: 05/05/2023]
Abstract
Dynamic nuclear polarization (DNP) is investigated in the liquid state using a model system of Frémy's salt dissolved in water. Nuclear magnetic resonance signal enhancements at 0.34 and 3.4 T of the bulk water protons are recorded as a function of the irradiation time and the polarizer concentration. The build-up rates are consistent with the T(1n) of the observed water protons at room temperature (for 9 GHz/0.34 T) and for about 50 ± 10 °C at 94 GHz/3.4 T. At 94 GHz/3.4 T, we observe in our setup a maximal enhancement of -50 at 25 mM polarizer concentration. The use of Frémy's salt allows the determination of the saturation factors at 94 GHz by pulsed ELDOR experiments. The results are well consistent with the Overhauser DNP mechanism and indicate that higher enhancements at this intermediate frequency require higher sample temperatures.
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Affiliation(s)
- M.-T. Türke
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - M. Bennati
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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31
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Lingwood MD, Sederman AJ, Mantle MD, Gladden LF, Han S. Overhauser dynamic nuclear polarization amplification of NMR flow imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 216:94-100. [PMID: 22329973 DOI: 10.1016/j.jmr.2012.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 05/31/2023]
Abstract
We describe the first study comparing the ability of phase shift velocity imaging and Overhauser dynamic nuclear polarization (DNP)-enhanced imaging to generate contrast for visualizing the flow of water. Prepolarization of water by the Overhauser DNP mechanism is performed in the 0.35T fringe field of an unshielded 2.0T non-clinical MRI magnet, followed by the rapid transfer of polarization-enhanced water to the 2.0T imaging location. This technique, previously named remotely enhanced liquids for image contrast (RELIC), produces a continuous flow of hyperpolarized water and gives up to an -8.2-fold enhanced signal within the image with respect to thermally polarized signal at 2.0T. Using flow through a cylindrical expansion phantom as a model system, spin-echo intensity images with DNP are compared to 3D phase shift velocity images to illustrate the complementary information available from the two techniques. The spin-echo intensity images enhanced with DNP show that the levels of enhancement provide an estimate of the transient propagation of flow, while the phase shift velocity images quantitatively measure the velocity of each imaging voxel. Phase shift velocity images acquired with and without DNP show that DNP weights velocity values towards those of the inflowing (DNP-enhanced) water, while velocity images without DNP more accurately reflect the average steady-state velocity of each voxel. We conclude that imaging with DNP prepolarized water better captures the transient path of water shortly after injection, while phase shift velocity imaging is best for quantifying the steady-state flow of water throughout the entire phantom.
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Affiliation(s)
- Mark D Lingwood
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA
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32
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Krummenacker JG, Denysenkov VP, Terekhov M, Schreiber LM, Prisner TF. DNP in MRI: an in-bore approach at 1.5 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 215:94-99. [PMID: 22248644 DOI: 10.1016/j.jmr.2011.12.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 12/16/2011] [Accepted: 12/18/2011] [Indexed: 05/31/2023]
Abstract
We have used liquid state ("Overhauser") Dynamic Nuclear Polarization (DNP) to significantly enhance the signal to noise ratio (SNR) of Magnetic Resonance Imaging (MRI). For the first time this was achieved by hyperpolarizing directly in the MRI-scanner field of 1.5 T in continuous flow mode and immediately delivering the hyperpolarized substance to the imaging site to ensure maximum contrast between hyperpolarized sample and sample at thermal polarization. We achieve a maximum absolute signal enhancement factor of 98; while the hyperpolarized sample is transported at a flow rate of up to 30 ml/h yielding an average flow speed up to 470 mm/s over a distance of approximately 80 mm. A spatial imaging resolution of 100 μm with a signal to noise ratio of 25 was achieved on the flowing sample. Application to MRI contrast enhancement or microfluidic imaging can be envisaged immediately.
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Affiliation(s)
- Jan G Krummenacker
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany.
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