1
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Jabbour R, Raran-Kurussi S, Agarwal V, Equbal A. Tailoring solid-state DNP methods to the study of α-synuclein LLPS. Biophys Chem 2024; 313:107303. [PMID: 39126968 DOI: 10.1016/j.bpc.2024.107303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 07/11/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024]
Abstract
Dynamic Nuclear Polarization (DNP) is a technique that leverages the quantum sensing capability of electron spins to enhance the sensitivity of nuclear magnetic resonance (NMR) signals, especially for insensitive samples. Glassing agents play a crucial role in the DNP process by facilitating the transfer of polarization from the unpaired electron spins to the nuclear spins along with cryoprotection of biomolecules. DNPjuice comprising of glycerol-d8/D2O/H2O has been extensively used for this purpose over the past two decades. Polyethylene glycol (PEG), also used as a cryoprotectant, is often used as a crowding agent in experimental setups to mimic cellular conditions, particularly the invitro preparation of liquid-liquid phase separated (LLPS) condensates. In this study, we investigate the efficacy of PEG as an alternative to glycerol in the DNP juice, critical for signal enhancement. The modified DNP matrix leads to high DNP enhancement which enables direct study of LLPS condensates by solid-state DNP methods without adding any external constituents. An indirect advantage of employing PEG is that the PEG signals appear at ∼72.5 ppm and are relatively well-separated from the aliphatic region of the protein spectra. Large cross-effect DNP enhancement is attained for 13C-glycine by employing the PEG-water mixture as a glassing agent and ASYMPOL-POK as the state-of-art polarizing agent, without any deuteration. The DNP enhancement and the buildup rates are similar to results obtained with DNP juice, conforming to that PEG serves as a good candidate for both inducing crowding and glassing agent in the study of LLPS.
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Affiliation(s)
- Ribal Jabbour
- Center for Quantum and Topological Systems, New York University Abu Dhabi, United Arab Emirates; Department of Chemistry, New York University Abu Dhabi, United Arab Emirates
| | | | - Vipin Agarwal
- Tata Institute of Fundamental Research Hyderabad, Hyderabad 500046, Telangana, India.
| | - Asif Equbal
- Center for Quantum and Topological Systems, New York University Abu Dhabi, United Arab Emirates; Department of Chemistry, New York University Abu Dhabi, United Arab Emirates.
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2
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Katz I, Schmidt A, Ben-Shir I, Javitt M, Kouřil K, Capozzi A, Meier B, Lang A, Pokroy B, Blank A. Long-lived enhanced magnetization-A practical metabolic MRI contrast material. SCIENCE ADVANCES 2024; 10:eado2483. [PMID: 38996017 PMCID: PMC11244432 DOI: 10.1126/sciadv.ado2483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 06/06/2024] [Indexed: 07/14/2024]
Abstract
Noninvasive tracking of biochemical processes in the body is paramount in diagnostic medicine. Among the leading techniques is spectroscopic magnetic resonance imaging (MRI), which tracks metabolites with an amplified (hyperpolarized) magnetization signal injected into the subject just before scanning. Traditionally, the brief enhanced magnetization period of these agents limited clinical imaging. We propose a solution based on amalgamating two materials-one having diagnostic-metabolic activity and the other characterized by robust magnetization retention. This combination slows the magnetization decay in the diagnostic metabolic probe, which receives continuously replenished magnetization from the companion material. Thus, it extends the magnetization lifetime in some of our measurements to beyond 4 min, with net magnetization enhanced by more than four orders of magnitude. This could allow the metabolic probes to remain magnetized from injection until they reach the targeted organ, improving tissue signatures in clinical imaging. Upon validation, this metabolic MRI technique promises wide-ranging clinical applications, including diagnostic imaging, therapeutic monitoring, and posttreatment surveillance.
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Affiliation(s)
- Itai Katz
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Asher Schmidt
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Ira Ben-Shir
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | | | - Karel Kouřil
- Institute of Biological Interfaces 4, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
| | - Andrea Capozzi
- LIFMET, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), Station 6, 1015 Lausanne, Switzerland
- HYPERMAG, Department of Health Technology, Technical University of Denmark, Building 349, 2800 Kgs Lyngby, Denmark
| | - Benno Meier
- Institute of Biological Interfaces 4, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany
| | - Arad Lang
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Boaz Pokroy
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Aharon Blank
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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3
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Sezer D. Non-perturbative treatment of the solid effect of dynamic nuclear polarization. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2023; 4:129-152. [PMID: 37904797 PMCID: PMC10583281 DOI: 10.5194/mr-4-129-2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/25/2023] [Indexed: 11/01/2023]
Abstract
In the solid effect of dynamic nuclear polarization (DNP), the concerted flips of the electronic and nuclear spins, which are needed for polarization transfer, are induced by the microwaves. Commonly, the effect of the microwaves is modeled by a rate process whose rate constant is determined perturbatively. According to quantum mechanics, however, the coherent microwave excitation leads to Rabi nutation, which corresponds to a rotation rather than a rate process. Here we reconcile the coherent effect of the microwaves with the description by rate equations by focusing only on the steady state of the spin dynamics. We show that the phenomenological rate constants describing the synchronous excitation of the electronic and nuclear spins can be selected such that the description by rate equations yields the same steady state as the exact quantum-mechanical treatment. The resulting non-perturbative rates differ from the classical, perturbative ones and remain valid also at the high microwave powers used in modern-day DNP. Our treatment of the solid effect highlights the role of the coherences in the mechanistic steps of polarization transfer and reveals the importance of the dispersive (i.e., out-of-phase) component of the EPR line. Interestingly, the multiplicative dependence of the DNP enhancement on the dispersive EPR component was intuited in the very first report of the solid effect in liquids . The time-domain description of the solid effect developed here is extendable to liquids, where the dipolar interaction changes randomly in time due to molecular diffusion.
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Affiliation(s)
- Deniz Sezer
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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4
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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: 64] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [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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5
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Cerofolini L, Parigi G, Ravera E, Fragai M, Luchinat C. Solid-state NMR methods for the characterization of bioconjugations and protein-material interactions. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 122:101828. [PMID: 36240720 DOI: 10.1016/j.ssnmr.2022.101828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/26/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Protein solid-state NMR has evolved dramatically over the last two decades, with the development of new hardware and sample preparation methodologies. This technique is now ripe for complex applications, among which one can count bioconjugation, protein chemistry and functional biomaterials. In this review, we provide our account on this aspect of protein solid-state NMR.
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Affiliation(s)
- Linda Cerofolini
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Giacomo Parigi
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Enrico Ravera
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy; Florence Data Science, Università degli Studi di Firenze, Italy.
| | - Marco Fragai
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy.
| | - Claudio Luchinat
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy.
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6
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Perras FA, Carnahan SL, Lo WS, Ward CJ, Yu J, Huang W, Rossini AJ. Hybrid quantum-classical simulations of magic angle spinning dynamic nuclear polarization in very large spin systems. J Chem Phys 2022; 156:124112. [DOI: 10.1063/5.0086530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Solid-state nuclear magnetic resonance can be enhanced using unpaired electron spins with a method known as dynamic nuclear polarization (DNP). Fundamentally, DNP involves ensembles of thousands of spins, a scale that is difficult to match computationally. This scale prevents us from gaining a complete understanding of the spin dynamics and applying simulations to design sample formulations. We recently developed an ab initio model capable of calculating DNP enhancements in systems of up to ∼1000 nuclei; however, this scale is insufficient to accurately simulate the dependence of DNP enhancements on radical concentration or magic angle spinning (MAS) frequency. We build on this work by using ab initio simulations to train a hybrid model that makes use of a rate matrix to treat nuclear spin diffusion. We show that this model can reproduce the MAS rate and concentration dependence of DNP enhancements and build-up time constants. We then apply it to predict the DNP enhancements in core–shell metal-organic-framework nanoparticles and reveal new insights into the composition of the particles’ shells.
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Affiliation(s)
| | - Scott L. Carnahan
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Wei-Shang Lo
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Charles J. Ward
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Jiaqi Yu
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Wenyu Huang
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Aaron J. Rossini
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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7
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Stern Q, Cousin SF, Mentink-Vigier F, Pinon AC, Elliott SJ, Cala O, Jannin S. Direct observation of hyperpolarization breaking through the spin diffusion barrier. SCIENCE ADVANCES 2021; 7:7/18/eabf5735. [PMID: 33931450 PMCID: PMC8087418 DOI: 10.1126/sciadv.abf5735] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/11/2021] [Indexed: 05/02/2023]
Abstract
Dynamic nuclear polarization (DNP) is a widely used tool for overcoming the low intrinsic sensitivity of nuclear magnetic resonance spectroscopy and imaging. Its practical applicability is typically bounded, however, by the so-called "spin diffusion barrier," which relates to the poor efficiency of polarization transfer from highly polarized nuclei close to paramagnetic centers to bulk nuclei. A quantitative assessment of this barrier has been hindered so far by the lack of general methods for studying nuclear polarization flow in the vicinity of paramagnetic centers. Here, we fill this gap and introduce a general set of experiments based on microwave gating that are readily implemented. We demonstrate the versatility of our approach in experiments conducted between 1.2 and 4.2 K in static mode and at 100 K under magic angle spinning (MAS)-conditions typical for dissolution DNP and MAS-DNP-and directly observe the marked dependence of polarization flow on temperature.
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Affiliation(s)
- Quentin Stern
- Univ Lyon, CNRS, ENS Lyon, UCBL, Université de Lyon, CRMN UMR 5280, 69100 Villeurbanne, France.
| | - Samuel François Cousin
- Univ Lyon, CNRS, ENS Lyon, UCBL, Université de Lyon, CRMN UMR 5280, 69100 Villeurbanne, France
| | - Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, USA
| | | | - Stuart James Elliott
- Department of Chemistry, Crown Street, University of Liverpool, Liverpool L69 7ZD, UK
| | - Olivier Cala
- Univ Lyon, CNRS, ENS Lyon, UCBL, Université de Lyon, CRMN UMR 5280, 69100 Villeurbanne, France
| | - Sami Jannin
- Univ Lyon, CNRS, ENS Lyon, UCBL, Université de Lyon, CRMN UMR 5280, 69100 Villeurbanne, France
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8
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de Oliveira M, Herr K, Brodrecht M, Haro-Mares NB, Wissel T, Klimavicius V, Breitzke H, Gutmann T, Buntkowsky G. Solvent-free dynamic nuclear polarization enhancements in organically modified mesoporous silica. Phys Chem Chem Phys 2021; 23:12559-12568. [PMID: 34027938 DOI: 10.1039/d1cp00985k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
High-field dynamic nuclear polarization is a powerful tool for the structural characterization of species on the surface of porous materials or nanoparticles. For these studies the main source of polarization are radical-containing solutions which are added by post-synthesis impregnation of the sample. Although this strategy is very efficient for a wide variety of materials, the presence of the solvent may influence the chemistry of functional species of interest. Here we address the development of a comprehensive strategy for solvent-free DNP enhanced NMR characterization of functional (target) species on the surface of mesoporous silica (SBA-15). The strategy includes the partial functionalization of the silica surface with Carboxy-Proxyl nitroxide radicals and target Fmoc-Glycine functional groups. As a proof of principle, we have observed for the first time DNP signal enhancements, using the solvent-free approach, for 13C{1H} CPMAS signals corresponding to organic functionalities on the silica surface. DNP enhancements of up to 3.4 were observed for 13C{1H} CPMAS, corresponding to an experimental time save of about 12 times. This observation opens the possibility for the DNP-NMR study of surface functional groups without the need of a solvent, allowing, for example, the characterization of catalytic reactions occurring on the surface of mesoporous systems of interest. For 29Si with direct polarization NMR, up to 8-fold DNP enhancements were obtained. This 29Si signal enhancement is considerably higher than the obtained with similar approaches reported in literature. Finally, from DNP enhancement profiles we conclude that cross-effect is probably the dominant polarization transfer mechanism.
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Affiliation(s)
- Marcos de Oliveira
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany. and São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP, Brazil.
| | - Kevin Herr
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Martin Brodrecht
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Nadia B Haro-Mares
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Till Wissel
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Vytautas Klimavicius
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany. and Institute of Chemical Physics, Vilnius University, Sauletekio av. 3, LT-10257 Vilnius, Lithuania
| | - Hergen Breitzke
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Torsten Gutmann
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Gerd Buntkowsky
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
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9
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Järvinen J, Zvezdov D, Ahokas J, Sheludiakov S, Lehtonen L, Vasiliev S, Vlasenko L, Ishikawa Y, Fujii Y. Dynamic nuclear polarization and ESR hole burning in As doped silicon. Phys Chem Chem Phys 2020; 22:10227-10237. [PMID: 32352086 DOI: 10.1039/c9cp06859g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an experimental study of the Dynamic Nuclear Polarization (DNP) of 29Si nuclei in silicon crystals of natural abundance doped with As in the temperature range 0.1-1 K and in a strong magnetic field of 4.6 T. This ensures a very high degree of electron spin polarization, extremely slow nuclear relaxation and optimal conditions for realization of Overhauser and resolved solid effects. We found that the solid effect DNP leads to the appearance of a pattern of holes and peaks in the ESR line, separated by the super-hyperfine interaction between the donor electron and 29Si nuclei closest to the donor. On the contrary, the Overhauser effect DNP mainly affects the remote 29Si nuclei having the weakest interaction with the donor electron. This leads to the appearance of a very narrow (≈3 mG wide) hole in the ESR line. We studied relaxation of the holes after burning, which is caused by the nuclear spin diffusion. Analyzing the dynamics of the hole in the spectrum with a simple one-dimensional diffusion model leads to a value of the diffusion coefficient D = 8(3) × 10-9 G2 s-1. Our data indicate that the spin diffusion is not completely prevented even in the frozen core near the donors. The emergence of the narrow hole after the Overhauser DNP may be explained by a partial "softening" of the frozen core caused by decoupling of the donor electron and remote 29Si nuclei.
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Affiliation(s)
- J Järvinen
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland.
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10
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Gennaro A, Karabanov A, Potapov A, Köckenberger W. Heteronuclear DNP of 1H and 19F nuclei using BDPA as a polarizing agent. Phys Chem Chem Phys 2020; 22:7803-7816. [DOI: 10.1039/d0cp00892c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study reveals heteronuclear-thermal mixing – a novel mechanism of dynamic nuclear polarization in a system with 1H and 19F nuclei.
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Affiliation(s)
- Antonio Gennaro
- School of Physics and Astronomy
- University of Nottingham
- Nottingham
- UK
| | | | - Alexey Potapov
- School of Physics and Astronomy
- University of Nottingham
- Nottingham
- UK
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11
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Perras FA, Pruski M. Linear-scaling ab initio simulations of spin diffusion in rotating solids. J Chem Phys 2019; 151:034110. [PMID: 31325939 DOI: 10.1063/1.5099146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We investigated the utility of locally restricting the basis sets involved in low-order correlations in Liouville space (LCL) calculations of spin diffusion. Using well-known classical models of spin diffusion, we describe a rationale for selecting the optimal basis set for such calculations. We then show that the use of these locally restricted basis sets provides the same computational accuracy as the full LCL set while reducing the computational time by several orders of magnitude. Speeding up the calculations also enables us to use higher maximum spin orders and increase the computational accuracy. Furthermore, unlike exact and full LCL calculations, locally restricted LCL calculations scale linearly with the system size and should thus enable the ab initio study of spin diffusion in spin systems containing several thousand spins.
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12
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Kundu K, Feintuch A, Vega S. Theoretical Aspects of the Cross Effect Enhancement of Nuclear Polarization under Static Dynamic Nuclear Polarization Conditions. J Phys Chem Lett 2019; 10:1769-1778. [PMID: 30864810 DOI: 10.1021/acs.jpclett.8b03615] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this study, we perform quantum calculations of the spin dynamics of a small spin system that includes nine coupled electrons and one nucleus placed in an external magnetic field and exposed to microwave irradiation. This is an extension of a previous work in which we have demonstrated on a system of 11 coupled electron spins the dynamics of the electron polarizations composing the electron paramagnetic resonance (EPR) line during static dynamic nuclear polarization (DNP) experiments. There we have shown that the electron polarizations are determined by a spectral diffusion process, induced by the dipolar interaction and cross-relaxation. Additionally, we showed that a distinction had to be made between strong and weak dipolar-coupled systems relative to the inhomogeneity of the EPR line with only the first behaving according to the thermal mixing DNP (with two electron spin temperatures) description. The EPR spectra in the weak and strong dipolar interaction cases show different types of spectral features. In the extended spin system, we again make a distinction between weak and strong electron-electron interactions and show that the DNP spectra for the two cases are different in nature but that the DNP spectra can be derived in all cases from the EPR line shapes using the indirect cross effect.
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Affiliation(s)
- Krishnendu Kundu
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Akiva Feintuch
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Shimon Vega
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot 76100 , Israel
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13
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Kundu K, Cohen MR, Feintuch A, Goldfarb D, Vega S. Experimental quantification of electron spectral-diffusion under static DNP conditions. Phys Chem Chem Phys 2018; 21:478-489. [PMID: 30534700 DOI: 10.1039/c8cp05930f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamic Nuclear Polarization (DNP) is an efficient technique for enhancing NMR signals by utilizing the large polarization of electron spins to polarize nuclei. The mechanistic details of the polarization transfer process involve the depolarization of the electrons resulting from microwave (MW) irradiation (saturation), as well as electron-electron cross-relaxation occurring during the DNP experiment. Recently, electron-electron double resonance (ELDOR) experiments have been performed under DNP conditions to map the depolarization profile along the EPR spectrum as a consequence of spectral diffusion. A phenomenological model referred to as the eSD model was developed earlier to describe the spectral diffusion process and thus reproduce the experimental results of electron depolarization. This model has recently been supported by quantum mechanical calculations on a small dipolar coupled electron spin system, experiencing dipolar interaction based cross-relaxation. In the present study, we performed a series of ELDOR measurements on a solid glassy solution of TEMPOL radicals in an effort to substantiate the eSD model and test its predictability in terms of electron depolarization profiles, in the steady-state and under non-equilibrium conditions. The crucial empirical parameter in this model is ΛeSD, which reflects the polarization exchange rate among the electron spins. Here, we explore further the physical basis of this parameter by analyzing the ELDOR spectra measured in the temperature range of 3-20 K and radical concentrations of 20-40 mM. Simulations using the eSD model were carried out to determine the dependence of ΛeSD on temperature and concentration. We found that for the samples studied, ΛeSD is temperature independent. It, however, increases with a power of ∼2.6 of the concentration of TEMPOL, which is proportional to the average electron-electron dipolar interaction strength in the sample.
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Affiliation(s)
- Krishnendu Kundu
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
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14
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Leavesley A, Jain S, Kamniker I, Zhang H, Rajca S, Rajca A, Han S. Maximizing NMR signal per unit time by facilitating the e-e-n cross effect DNP rate. Phys Chem Chem Phys 2018; 20:27646-27657. [PMID: 30375593 PMCID: PMC6370975 DOI: 10.1039/c8cp04909b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamic nuclear polarization (DNP) efficiency is critically dependent on the properties of the radical, solvent, and solute constituting the sample system. In this study, we focused on the three spin e-e-n cross effect (CE)'s influence on the nuclear longitudinal relaxation time constant T1n, the build-up time constants of nuclear magnetic resonance (NMR) signal, TDNP and DNP-enhancement of NMR signal. The dipolar interaction strength between the electron spins driving the e-e-n process was systematically modulated using mono-, di-, tri-, and dendritic-nitroxide radicals, while maintaining a constant global electron spin concentration of 10 mM. Experimental results showed that an increase in electron spin clustering led to an increased electron spin depolarization, as mapped by electron double resonance (ELDOR), and a dramatically shortened T1n and TDNP time constants under static and magic angle spinning (MAS) conditions. A theoretical analysis reveals that strong e-e interactions, caused by electron spin clustering, increase the CE rate. The three spin e-e-n CE is a hitherto little recognized mechanism for shortening T1n and TDNP in solid-state NMR experiments at cryogenic temperatures, and offers a design principle to enhance the effective CE DNP enhancement per unit time. Fast CE rates will benefit DNP at liquid helium temperatures, or at higher magnetic fields and pulsed DNP, where slow e-e-n polarization transfer rate is a key bottleneck to achieving maximal DNP performance.
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Affiliation(s)
- Alisa Leavesley
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
| | - Sheetal Jain
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
| | - Ilia Kamniker
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
| | - Hui Zhang
- Department of Chemistry, University of Nebraska, Lincoln, NE
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA
- Department of Chemical Engineering, University of California, Santa Barbara, CA
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15
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Perras FA, Pruski M. Large-scale ab initio simulations of MAS DNP enhancements using a Monte Carlo optimization strategy. J Chem Phys 2018; 149:154202. [PMID: 30342444 DOI: 10.1063/1.5042651] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Magic-angle-spinning (MAS) dynamic nuclear polarization (DNP) has recently emerged as a powerful technology enabling otherwise unrealistic solid-state NMR experiments. The simulation of DNP processes which might, for example, aid in refining the experimental conditions or the design of better performing polarizing agents, is, however, plagued with significant challenges, often limiting the system size to only 3 spins. Here, we present the first approach to fully ab initio large-scale simulations of MAS DNP enhancements. The Landau-Zener equation is used to treat all interactions concerning electron spins, and the low-order correlations in the Liouville space method is used to accurately treat the spin diffusion, as well as its MAS speed dependence. As the propagator cannot be stored, a Monte Carlo optimization method is used to determine the steady-state enhancement factors. This new software is employed to investigate the MAS speed dependence of the enhancement factors in large spin systems where spin diffusion is of importance, as well as to investigate the impacts of solvent and polarizing agent deuteration on the performance of MAS DNP.
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16
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Ravera E, Takis PG, Fragai M, Parigi G, Luchinat C. NMR Spectroscopy and Metal Ions in Life Sciences. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800875] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP); Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Panteleimon G. Takis
- Giotto Biotech S.R.L.; Via Madonna del Piano 6 50019 Sesto Fiorentino (FI) Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP); Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP); Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP); Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
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17
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Rodríguez-Arias I, Rosso A, De Luca A. Eigenstate versus Zeeman-based approaches to the solid effect. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:689-698. [PMID: 29460312 DOI: 10.1002/mrc.4724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 02/05/2018] [Accepted: 02/06/2018] [Indexed: 06/08/2023]
Abstract
The solid effect is one of the simplest and most effective mechanisms for dynamic nuclear polarization. It involves the exchange of polarization between one electron and one nuclear spin coupled via the hyperfine interaction. Even for such a small spin system, the theoretical understanding is complicated by the contact with the lattice and the microwave irradiation. Both being weak, they can be treated within perturbation theory. In this work, we analyze the two most popular perturbation schemes: the Zeeman and the eigenstate-based approaches, which differ in the way the hyperfine interaction is treated. For both schemes, we derive from first principles an effective Liouville equation that describes the density matrix of the spin system; we then study numerically the behavior of the nuclear polarization for several values of the hyperfine coupling. In general, we obtain that the Zeeman-based approach underestimates the value of the nuclear polarization. By performing a projection onto the diagonal part of the spin-system density matrix, we are able to understand the origin of the discrepancy, which is due to the presence of parasite leakage transitions appearing whenever the Zeeman basis is employed.
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Affiliation(s)
- Inés Rodríguez-Arias
- LPTMS, CNRS, University of Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Alberto Rosso
- LPTMS, CNRS, University of Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Andrea De Luca
- The Rudolf Peierls Centre for Theoretical Physics, Oxford University, Oxford OX1 3NP, UK
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18
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Wittmann JJ, Eckardt M, Harneit W, Corzilius B. Electron-driven spin diffusion supports crossing the diffusion barrier in MAS DNP. Phys Chem Chem Phys 2018; 20:11418-11429. [PMID: 29645035 DOI: 10.1039/c8cp00265g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Dynamic nuclear polarization (DNP) can be applied to enhance the sensitivity of solid-state NMR experiments by several orders of magnitude due to microwave-driven transfer of spin polarization from unpaired electrons to nuclei. While the underlying quantum mechanical aspects are sufficiently well understood on a microscopic level, the exact description of the large-scale spin dynamics, usually involving hundreds to thousands of nuclear spins per electron, is still lacking consensus. Generally, it is assumed that nuclear hyperpolarization can only be observed on nuclei which do not experience strong influence of the unpaired electrons and thus being significantly removed from the paramagnetic polarizing agents. At the same time, sufficiently strong hyperfine interaction is required for DNP transfer. Therefore, efficient nuclear spin diffusion from the strongly-interacting nuclei to the NMR-observable bulk is considered to be essential for efficient nuclear hyperpolarization. Based on experimental results obtained on the endohedral fullerene N@C60 as a polarizing agent sparsely diluted in C60, we discuss the effect of the spin-diffusion barrier. We introduce electron-driven spin diffusion (EDSD) as a novel mechanism for nuclear polarization transfer in the proximity of an electron spin which is particularly relevant under magic-angle spinning (MAS) DNP conditions.
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Affiliation(s)
- Johannes J Wittmann
- Institute of Physical and Theoretical Chemistry, Institute of Biophysical Chemistry, and Biomolecular Magnetic Resonance Center (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438 Frankfurt, Germany.
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19
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Kundu K, Feintuch A, Vega S. Electron-Electron Cross-Relaxation and Spectral Diffusion during Dynamic Nuclear Polarization Experiments on Solids. J Phys Chem Lett 2018; 9:1793-1802. [PMID: 29553271 DOI: 10.1021/acs.jpclett.8b00090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recently it has been shown that experimental electron-electron double resonance (ELDOR) spectra of amorphous glasses containing free radicals with inhomogeneously broadened electron paramagnetic resonance (EPR) spectra can be analyzed using a set of coupled rate equations for the electron polarizations of frequency bins composing these spectra, named the eSD (electron spectral diffusion) model. The rate matrix defining these equations has elements depending on the microwave, the spin-lattice relaxation rates and on eSD rate constants responsible for polarization exchange. In this study, we show that in addition to the static dipolar flip-flop terms in the Hamiltonian a zero-quantum electron cross-relaxation mechanism can be responsible for the polarization exchange process in our samples. This conclusion was reached by calculating the EPR lineshapes of a system of 11 coupled electrons exposed to microwave irradiation using an eigenstate population rate equation derived from the spin density vector rate equation in Liouville space. These equations involve all terms of the Hamiltonian and in addition rate constants representing longitudinal relaxation and cross-relaxation mechanisms as well as MW irradiation. The results of these calculations are compared with the results obtained from the eSD model.
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Affiliation(s)
- Krishnendu Kundu
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot - 76100 , Israel
| | - Akiva Feintuch
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot - 76100 , Israel
| | - Shimon Vega
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot - 76100 , Israel
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20
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Mentink-Vigier F, Vega S, De Paëpe G. Fast and accurate MAS-DNP simulations of large spin ensembles. Phys Chem Chem Phys 2018; 19:3506-3522. [PMID: 28093594 DOI: 10.1039/c6cp07881h] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A deeper understanding of parameters affecting Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP), an emerging nuclear magnetic resonance hyperpolarization method, is crucial for the development of new polarizing agents and the successful implementation of the technique at higher magnetic fields (>10 T). Such progress is currently impeded by computational limitation which prevents the simulation of large spin ensembles (electron as well as nuclear spins) and to accurately describe the interplay between all the multiple key parameters at play. In this work, we present an alternative approach to existing cross-effect and solid-effect MAS-DNP codes that yields fast and accurate simulations. More specifically we describe the model, the associated Liouville-based formalism (Bloch-type derivation and/or Landau-Zener approximations) and the linear time algorithm that allows computing MAS-DNP mechanisms with unprecedented time savings. As a result, one can easily scan through multiple parameters and disentangle their mutual influences. In addition, the simulation code is able to handle multiple electrons and protons, which allows probing the effect of (hyper)polarizing agents concentration, as well as fully revealing the interplay between the polarizing agent structure and the hyperfine couplings, nuclear dipolar couplings, nuclear relaxation times, both in terms of depolarization effect, but also of polarization gain and buildup times.
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Affiliation(s)
- Frédéric Mentink-Vigier
- Univ. Grenoble Alpes, INAC, MEM, F-38000 Grenoble, France and CEA, INAC, MEM, F-38000 Grenoble, France.
| | - Shimon Vega
- Weizmann institute of Science, Rehovot, Israel
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, INAC, MEM, F-38000 Grenoble, France and CEA, INAC, MEM, F-38000 Grenoble, France.
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21
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Lilly Thankamony AS, Wittmann JJ, Kaushik M, Corzilius B. Dynamic nuclear polarization for sensitivity enhancement in modern solid-state NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 102-103:120-195. [PMID: 29157490 DOI: 10.1016/j.pnmrs.2017.06.002] [Citation(s) in RCA: 278] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/03/2017] [Accepted: 06/08/2017] [Indexed: 05/03/2023]
Abstract
The field of dynamic nuclear polarization has undergone tremendous developments and diversification since its inception more than 6 decades ago. In this review we provide an in-depth overview of the relevant topics involved in DNP-enhanced MAS NMR spectroscopy. This includes the theoretical description of DNP mechanisms as well as of the polarization transfer pathways that can lead to a uniform or selective spreading of polarization between nuclear spins. Furthermore, we cover historical and state-of-the art aspects of dedicated instrumentation, polarizing agents, and optimization techniques for efficient MAS DNP. Finally, we present an extensive overview on applications in the fields of structural biology and materials science, which underlines that MAS DNP has moved far beyond the proof-of-concept stage and has become an important tool for research in these fields.
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Affiliation(s)
- Aany Sofia Lilly Thankamony
- Institute of Physical and Theoretical Chemistry, Institute of Biophysical Chemistry, and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438 Frankfurt, Germany
| | - Johannes J Wittmann
- Institute of Physical and Theoretical Chemistry, Institute of Biophysical Chemistry, and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438 Frankfurt, Germany
| | - Monu Kaushik
- Institute of Physical and Theoretical Chemistry, Institute of Biophysical Chemistry, and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438 Frankfurt, Germany
| | - Björn Corzilius
- Institute of Physical and Theoretical Chemistry, Institute of Biophysical Chemistry, and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438 Frankfurt, Germany.
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22
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Jain SK, Mathies G, Griffin RG. Off-resonance NOVEL. J Chem Phys 2017; 147:164201. [PMID: 29096491 PMCID: PMC5659863 DOI: 10.1063/1.5000528] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/10/2017] [Indexed: 11/14/2022] Open
Abstract
Dynamic nuclear polarization (DNP) is theoretically able to enhance the signal in nuclear magnetic resonance (NMR) experiments by a factor γe/γn, where γ's are the gyromagnetic ratios of an electron and a nuclear spin. However, DNP enhancements currently achieved in high-field, high-resolution biomolecular magic-angle spinning NMR are well below this limit because the continuous-wave DNP mechanisms employed in these experiments scale as ω0-n where n ∼ 1-2. In pulsed DNP methods, such as nuclear orientation via electron spin-locking (NOVEL), the DNP efficiency is independent of the strength of the main magnetic field. Hence, these methods represent a viable alternative approach for enhancing nuclear signals. At 0.35 T, the NOVEL scheme was demonstrated to be efficient in samples doped with stable radicals, generating 1H NMR enhancements of ∼430. However, an impediment in the implementation of NOVEL at high fields is the requirement of sufficient microwave power to fulfill the on-resonance matching condition, ω0I = ω1S, where ω0I and ω1S are the nuclear Larmor and electron Rabi frequencies, respectively. Here, we exploit a generalized matching condition, which states that the effective Rabi frequency, ω1Seff, matches ω0I. By using this generalized off-resonance matching condition, we generate 1H NMR signal enhancement factors of 266 (∼70% of the on-resonance NOVEL enhancement) with ω1S/2π = 5 MHz. We investigate experimentally the conditions for optimal transfer of polarization from electrons to 1H both for the NOVEL mechanism and the solid-effect mechanism and provide a unified theoretical description for these two historically distinct forms of DNP.
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Affiliation(s)
- Sheetal K Jain
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Guinevere Mathies
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert G Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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23
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Rogawski R, McDermott AE. New NMR tools for protein structure and function: Spin tags for dynamic nuclear polarization solid state NMR. Arch Biochem Biophys 2017; 628:102-113. [PMID: 28623034 PMCID: PMC5815514 DOI: 10.1016/j.abb.2017.06.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/05/2017] [Accepted: 06/12/2017] [Indexed: 12/13/2022]
Abstract
Magic angle spinning solid state NMR studies of biological macromolecules [1-3] have enabled exciting studies of membrane proteins [4,5], amyloid fibrils [6], viruses, and large macromolecular assemblies [7]. Dynamic nuclear polarization (DNP) provides a means to enhance detection sensitivity for NMR, particularly for solid state NMR, with many recent biological applications and considerable contemporary efforts towards elaboration and optimization of the DNP experiment. This review explores precedents and innovations in biological DNP experiments, especially highlighting novel chemical biology approaches to introduce the radicals that serve as a source of polarization in DNP experiments.
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Affiliation(s)
- Rivkah Rogawski
- Department of Chemistry, Columbia University, NY, NY 10027, United States
| | - Ann E McDermott
- Department of Chemistry, Columbia University, NY, NY 10027, United States.
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24
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Buntkowsky G, Ivanov KL, Zimmermann H, Vieth HM. Coherent manipulation of non-thermal spin order in optical nuclear polarization experiments. J Chem Phys 2017; 146:114501. [PMID: 28330349 DOI: 10.1063/1.4976990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Time resolved measurements of Optical Nuclear Polarization (ONP) have been performed on hyperpolarized triplet states in molecular crystals created by light excitation. Transfer of the initial electron polarization to nuclear spins has been studied in the presence of radiofrequency excitation; the experiments have been performed with different pulse sequences using different doped molecular systems. The experimental results clearly demonstrate the dominant role of coherent mechanisms of spin order transfer, which manifest themselves in well pronounced oscillations. These oscillations are of two types, precessions and nutations, having characteristic frequencies, which are the same for the different molecular systems and the pulse sequences applied. Hence, precessions and nutations constitute a general feature of polarization transfer in ONP experiments. In general, coherent manipulation of spin order transfer creates a powerful resource for improving the performance of the ONP method, which paves the way to strong signal enhancement in nuclear magnetic resonance.
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Affiliation(s)
- Gerd Buntkowsky
- Fachbereich Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, Darmstadt 64287, Germany
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia
| | - Herbert Zimmermann
- Max-Planck-Institut für Medizinische Forschung, Heidelberg, Jahnstr. 29, 69120 Heidelberg, Germany
| | - Hans-Martin Vieth
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia
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25
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Leavesley A, Shimon D, Siaw TA, Feintuch A, Goldfarb D, Vega S, Kaminker I, Han S. Effect of electron spectral diffusion on static dynamic nuclear polarization at 7 Tesla. Phys Chem Chem Phys 2017; 19:3596-3605. [DOI: 10.1039/c6cp06893f] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Systematic investigation of DNP profiles at high radical concentrations and 7 T show that electron spectral diffusion directly impacts DNP processes.
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Affiliation(s)
- Alisa Leavesley
- Department of Chemistry and Biochemistry, University of California Santa Barbara
- Santa Barbara
- USA
| | | | - Ting Ann Siaw
- Department of Chemistry and Biochemistry, University of California Santa Barbara
- Santa Barbara
- USA
| | | | | | | | - Ilia Kaminker
- Department of Chemistry and Biochemistry, University of California Santa Barbara
- Santa Barbara
- USA
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California Santa Barbara
- Santa Barbara
- USA
- Department of Chemical Engineering
- University of California Santa Barbara
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26
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Grüning WR, Bieringer H, Schwarzwälder M, Gajan D, Bornet A, Vuichoud B, Milani J, Baudouin D, Veyre L, Lesage A, Jannin S, Bodenhausen G, Thieuleux C, Copéret C. Phenylazide Hybrid-Silica - Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures. Helv Chim Acta 2016. [DOI: 10.1002/hlca.201600122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wolfram R. Grüning
- Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 1-5/10 CH-8093 Zürich Switzerland
| | - Harald Bieringer
- Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 1-5/10 CH-8093 Zürich Switzerland
| | - Martin Schwarzwälder
- Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 1-5/10 CH-8093 Zürich Switzerland
| | - David Gajan
- Centre de Résonance Magnétique Nucléaire (RMN) à Très Hauts Champs; Institut des Sciences Analytiques [Centre National de la Recherche Scientifique (CNRS)/Ecole Normale Supérieure (ENS) Lyon/Université Claude Bernard Lyon 1 (UCBL)]; Université de Lyon; FR-69100 Villeurbanne France
| | - Aurélien Bornet
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1015 Lausanne Switzerland
| | - Basile Vuichoud
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1015 Lausanne Switzerland
| | - Jonas Milani
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1015 Lausanne Switzerland
| | - David Baudouin
- Laboratoire de Chimie, Catalyse, Polymères et Procédés (LC2P2); Unité Mixte de Recherche (UMR) 5265; Institut de Chimie de Lyon; CNRS-CPE Lyon-UCBL; CPE Lyon, Université de Lyon; FR-69100 Villeurbanne France
| | - Laurent Veyre
- Laboratoire de Chimie, Catalyse, Polymères et Procédés (LC2P2); Unité Mixte de Recherche (UMR) 5265; Institut de Chimie de Lyon; CNRS-CPE Lyon-UCBL; CPE Lyon, Université de Lyon; FR-69100 Villeurbanne France
| | - Anne Lesage
- Centre de Résonance Magnétique Nucléaire (RMN) à Très Hauts Champs; Institut des Sciences Analytiques [Centre National de la Recherche Scientifique (CNRS)/Ecole Normale Supérieure (ENS) Lyon/Université Claude Bernard Lyon 1 (UCBL)]; Université de Lyon; FR-69100 Villeurbanne France
| | - Sami Jannin
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1015 Lausanne Switzerland
| | - Geoffrey Bodenhausen
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne (EPFL); CH-1015 Lausanne Switzerland
- Département de Chimie; Ecole Normale Supérieure (ENS)-Paris Sciences et Lettres (PSL) Research University; FR-75005 Paris France
- Laboratoire de Biomolécules (LBM); Université Pierre et Marie Curie (UPMC), Université Paris 06; Sorbonnes Universités; FR-75005 Paris France
- Laboratoire de Biomolécules (LBM); Unité Mixte de Recherche (UMR) 7203; Centre National de la Recherche Scientifique (CNRS); FR-75005 Paris France
| | - Chloé Thieuleux
- Laboratoire de Chimie, Catalyse, Polymères et Procédés (LC2P2); Unité Mixte de Recherche (UMR) 5265; Institut de Chimie de Lyon; CNRS-CPE Lyon-UCBL; CPE Lyon, Université de Lyon; FR-69100 Villeurbanne France
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 1-5/10 CH-8093 Zürich Switzerland
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27
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Smith AN, Twahir UT, Dubroca T, Fanucci GE, Long JR. Molecular Rationale for Improved Dynamic Nuclear Polarization of Biomembranes. J Phys Chem B 2016; 120:7880-8. [PMID: 27434371 DOI: 10.1021/acs.jpcb.6b02885] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Dynamic nuclear polarization (DNP) enhanced solid-state NMR can provide orders of magnitude in signal enhancement. One of the most important aspects of obtaining efficient DNP enhancements is the optimization of the paramagnetic polarization agents used. To date, the most utilized polarization agents are nitroxide biradicals. However, the efficiency of these polarization agents is diminished when used with samples other than small molecule model compounds. We recently demonstrated the effectiveness of nitroxide labeled lipids as polarization agents for lipids and a membrane embedded peptide. Here, we systematically characterize, via electron paramagnetic (EPR), the dynamics of and the dipolar couplings between nitroxide labeled lipids under conditions relevant to DNP applications. Complemented by DNP enhanced solid-state NMR measurements at 600 MHz/395 GHz, a molecular rationale for the efficiency of nitroxide labeled lipids as DNP polarization agents is developed. Specifically, optimal DNP enhancements are obtained when the nitroxide moiety is attached to the lipid choline headgroup and local nitroxide concentrations yield an average e(-)-e(-) dipolar coupling of 47 MHz. On the basis of these measurements, we propose a framework for development of DNP polarization agents optimal for membrane protein structure determination.
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Affiliation(s)
- Adam N Smith
- Department of Chemistry, University of Florida , 214 Leigh Hall, P.O. Box 117200, Gainesville, Florida 32611, United States.,National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
| | - Umar T Twahir
- Department of Chemistry, University of Florida , 214 Leigh Hall, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Thierry Dubroca
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
| | - Gail E Fanucci
- Department of Chemistry, University of Florida , 214 Leigh Hall, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Joanna R Long
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States.,Department of Biochemistry & Molecular Biology, University of Florida , P.O. Box 100245, Gainesville, Florida 32610, United States
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28
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Akbey Ü, Oschkinat H. Structural biology applications of solid state MAS DNP NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 269:213-224. [PMID: 27095695 DOI: 10.1016/j.jmr.2016.04.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 06/05/2023]
Abstract
Dynamic Nuclear Polarization (DNP) has long been an aim for increasing sensitivity of nuclear magnetic resonance (NMR) spectroscopy, delivering spectra in shorter experiment times or of smaller sample amounts. In recent years, it has been applied in magic angle spinning (MAS) solid-state NMR to a large range of samples, including biological macromolecules and functional materials. New research directions in structural biology can be envisaged by DNP, facilitating investigations on very large complexes or very heterogeneous samples. Here we present a summary of state of the art DNP MAS NMR spectroscopy and its applications to structural biology, discussing the technical challenges and factors affecting DNP performance.
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Affiliation(s)
- Ümit Akbey
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
| | - Hartmut Oschkinat
- Leibniz Institute für Molekulare Pharmakologie (FMP), NMR Supported Structural Biology, Robert Roessle Str. 10, 13125 Berlin, Germany.
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29
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Viennet T, Viegas A, Kuepper A, Arens S, Gelev V, Petrov O, Grossmann TN, Heise H, Etzkorn M. Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603205] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Thibault Viennet
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Aldino Viegas
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Arne Kuepper
- Chemical Genomics Centre of the Max Planck Society; Otto-Hahn-Str. 15 44227 Dortmund Germany
| | - Sabine Arens
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Vladimir Gelev
- Faculty of Chemistry and Pharmacy; Sofia University; 1 James Bourchier Blvd. 1164 Sofia Bulgaria
| | - Ognyan Petrov
- Faculty of Chemistry and Pharmacy; Sofia University; 1 James Bourchier Blvd. 1164 Sofia Bulgaria
| | - Tom N. Grossmann
- Chemical Genomics Centre of the Max Planck Society; Otto-Hahn-Str. 15 44227 Dortmund Germany
- VU University Amsterdam; Department of Chemistry and Pharmaceutical Sciences; De Boelelaan 1083 1081 HV Amsterdam The Netherlands
| | - Henrike Heise
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Manuel Etzkorn
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
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30
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Viennet T, Viegas A, Kuepper A, Arens S, Gelev V, Petrov O, Grossmann TN, Heise H, Etzkorn M. Selective Protein Hyperpolarization in Cell Lysates Using Targeted Dynamic Nuclear Polarization. Angew Chem Int Ed Engl 2016; 55:10746-50. [DOI: 10.1002/anie.201603205] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Thibault Viennet
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Aldino Viegas
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Arne Kuepper
- Chemical Genomics Centre of the Max Planck Society; Otto-Hahn-Str. 15 44227 Dortmund Germany
| | - Sabine Arens
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Vladimir Gelev
- Faculty of Chemistry and Pharmacy; Sofia University; 1 James Bourchier Blvd. 1164 Sofia Bulgaria
| | - Ognyan Petrov
- Faculty of Chemistry and Pharmacy; Sofia University; 1 James Bourchier Blvd. 1164 Sofia Bulgaria
| | - Tom N. Grossmann
- Chemical Genomics Centre of the Max Planck Society; Otto-Hahn-Str. 15 44227 Dortmund Germany
- VU University Amsterdam; Department of Chemistry and Pharmaceutical Sciences; De Boelelaan 1083 1081 HV Amsterdam The Netherlands
| | - Henrike Heise
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
| | - Manuel Etzkorn
- Institute of Physical Biology; Heinrich Heine University; Universitätsstr. 1 40225 Düsseldorf Germany
- Institute of Complex Systems (ICS-6); Forschungszentrum Jülich; Wilhelm Jonen Strasse Jülich Germany
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31
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Siaw TA, Leavesley A, Lund A, Kaminker I, Han S. A versatile and modular quasi optics-based 200GHz dual dynamic nuclear polarization and electron paramagnetic resonance instrument. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:131-153. [PMID: 26920839 PMCID: PMC4770585 DOI: 10.1016/j.jmr.2015.12.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/19/2015] [Accepted: 12/21/2015] [Indexed: 05/12/2023]
Abstract
Solid-state dynamic nuclear polarization (DNP) at higher magnetic fields (>3T) and cryogenic temperatures (∼ 2-90K) has gained enormous interest and seen major technological advances as an NMR signal enhancing technique. Still, the current state of the art DNP operation is not at a state at which sample and freezing conditions can be rationally chosen and the DNP performance predicted a priori, but relies on purely empirical approaches. An important step towards rational optimization of DNP conditions is to have access to DNP instrumental capabilities to diagnose DNP performance and elucidate DNP mechanisms. The desired diagnoses include the measurement of the "DNP power curve", i.e. the microwave (MW) power dependence of DNP enhancement, the "DNP spectrum", i.e. the MW frequency dependence of DNP enhancement, the electron paramagnetic resonance (EPR) spectrum, and the saturation and spectral diffusion properties of the EPR spectrum upon prolonged MW irradiation typical of continuous wave (CW) DNP, as well as various electron and nuclear spin relaxation parameters. Even basic measurements of these DNP parameters require versatile instrumentation at high magnetic fields not commercially available to date. In this article, we describe the detailed design of such a DNP instrument, powered by a solid-state MW source that is tunable between 193 and 201 GHz and outputs up to 140 mW of MW power. The quality and pathway of the transmitted and reflected MWs is controlled by a quasi-optics (QO) bridge and a corrugated waveguide, where the latter couples the MW from an open-space QO bridge to the sample located inside the superconducting magnet and vice versa. Crucially, the versatility of the solid-state MW source enables the automated acquisition of frequency swept DNP spectra, DNP power curves, the diagnosis of MW power and transmission, and frequency swept continuous wave (CW) and pulsed EPR experiments. The flexibility of the DNP instrument centered around the QO MW bridge will provide an efficient means to collect DNP data that is crucial for understanding the relationship between experimental and sample conditions, and the DNP performance. The modularity of this instrumental platform is suitable for future upgrades and extensions to include new experimental capabilities to meet contemporary DNP needs, including the simultaneous operation of two or more MW sources, time domain DNP, electron double resonance measurements, pulsed EPR operation, or simply the implementation of higher power MW amplifiers.
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Affiliation(s)
- Ting Ann Siaw
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, United States
| | - Alisa Leavesley
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, United States
| | - Alicia Lund
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, United States
| | - Ilia Kaminker
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, United States.
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32
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Kaminker I, Shimon D, Hovav Y, Feintuch A, Vega S. Heteronuclear DNP of protons and deuterons with TEMPOL. Phys Chem Chem Phys 2016; 18:11017-41. [DOI: 10.1039/c5cp06689a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamic nuclear polarization (DNP) experiments on samples with several types of magnetic nuclei sometimes exhibit “cross-talk” between the nuclei, such as different nuclei having DNP spectra with similar shapes and enhancements.
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Affiliation(s)
| | - D. Shimon
- Weizmann Institute of Science
- Rehovot
- Israel
| | - Y. Hovav
- Weizmann Institute of Science
- Rehovot
- Israel
| | | | - S. Vega
- Weizmann Institute of Science
- Rehovot
- Israel
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33
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Perras FA, Reinig RR, Slowing II, Sadow AD, Pruski M. Effects of biradical deuteration on the performance of DNP: towards better performing polarizing agents. Phys Chem Chem Phys 2015; 18:65-9. [PMID: 26619055 DOI: 10.1039/c5cp06505d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study the effects of the deuteration of biradical polarizing agents on the efficiency of dynamic nuclear polarization (DNP) via the cross-effect. To this end, we synthesized a series of bTbK and TOTAPol biradicals with systematically increased deuterium substitution. The deuteration increases the radicals' relaxation time, thus contributing to a higher saturation factor and larger DNP enhancement, and reduces the pool of protons within the so-called spin diffusion barrier. Notably, we report that full or partial deuteration leads to improved DNP enhancement factors in standard samples, but also slows down the build-up of hyperpolarization. Improvements in DNP enhancements factors of up to 70% and time savings of up to 38% are obtained upon full deuteration. It is foreseen that this approach may be applied to other DNP polarizing agents thus enabling further sensitivity improvements.
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Affiliation(s)
- Frédéric A Perras
- U.S. DOE Ames Laboratory, Iowa State University, 230 Spedding Hall, Ames, IA 50011-3020, USA.
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34
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Lelli M, Chaudhari SR, Gajan D, Casano G, Rossini AJ, Ouari O, Tordo P, Lesage A, Emsley L. Solid-State Dynamic Nuclear Polarization at 9.4 and 18.8 T from 100 K to Room Temperature. J Am Chem Soc 2015; 137:14558-61. [PMID: 26555676 PMCID: PMC4671100 DOI: 10.1021/jacs.5b08423] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Efficient dynamic nuclear polarization
(DNP) in solids, which enables
very high sensitivity NMR experiments, is currently limited to temperatures
of around 100 K and below. Here we show how by choosing an adequate
solvent, 1H cross effect DNP enhancements of over 80 can
be obtained at 240 K. To achieve this we use the biradical TEKPol
dissolved in a glassy phase of ortho-terphenyl (OTP).
We study the solvent DNP enhancement of both TEKPol and BDPA in OTP
in the range from 100 to 300 K at 9.4 and 18.8 T. Surprisingly, we
find that the DNP enhancement decreases only relatively slowly for
temperatures below the glass transition of OTP (Tg = 243 K), and 1H enhancements around 15–20
at ambient temperature can be observed. We use this to monitor molecular
dynamic transitions in the pharmaceutically relevant solids Ambroxol
and Ibuprofen.
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Affiliation(s)
- Moreno Lelli
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - Sachin R Chaudhari
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - David Gajan
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - Gilles Casano
- Aix-Marseille Université, CNRS, ICR UMR 7273 , 13397 Marseille, France
| | - Aaron J Rossini
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Olivier Ouari
- Aix-Marseille Université, CNRS, ICR UMR 7273 , 13397 Marseille, France
| | - Paul Tordo
- Aix-Marseille Université, CNRS, ICR UMR 7273 , 13397 Marseille, France
| | - Anne Lesage
- Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
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35
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Can TV, Caporini MA, Mentink-Vigier F, Corzilius B, Walish JJ, Rosay M, Maas WE, Baldus M, Vega S, Swager TM, Griffin RG. Overhauser effects in insulating solids. J Chem Phys 2015; 141:064202. [PMID: 25134564 DOI: 10.1063/1.4891866] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report magic angle spinning, dynamic nuclear polarization (DNP) experiments at magnetic fields of 9.4 T, 14.1 T, and 18.8 T using the narrow line polarizing agents 1,3-bisdiphenylene-2-phenylallyl (BDPA) dispersed in polystyrene, and sulfonated-BDPA (SA-BDPA) and trityl OX063 in glassy glycerol/water matrices. The (1)H DNP enhancement field profiles of the BDPA radicals exhibit a significant DNP Overhauser effect (OE) as well as a solid effect (SE) despite the fact that these samples are insulating solids. In contrast, trityl exhibits only a SE enhancement. Data suggest that the appearance of the OE is due to rather strong electron-nuclear hyperfine couplings present in BDPA and SA-BDPA, which are absent in trityl and perdeuterated BDPA (d21-BDPA). In addition, and in contrast to other DNP mechanisms such as the solid effect or cross effect, the experimental data suggest that the OE in non-conducting solids scales favorably with magnetic field, increasing in magnitude in going from 5 T, to 9.4 T, to 14.1 T, and to 18.8 T. Simulations using a model two spin system consisting of an electron hyperfine coupled to a (1)H reproduce the essential features of the field profiles and indicate that the OE in these samples originates from the zero and double quantum cross relaxation induced by fluctuating hyperfine interactions between the intramolecular delocalized unpaired electrons and their neighboring nuclei, and that the size of these hyperfine couplings is crucial to the magnitude of the enhancements. Microwave power dependent studies show that the OE saturates at considerably lower power levels than the solid effect in the same samples. Our results provide new insights into the mechanism of the Overhauser effect, and also provide a new approach to perform DNP experiments in chemical, biophysical, and physical systems at high magnetic fields.
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Affiliation(s)
- T V Can
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M A Caporini
- Bruker BioSpin, Billerica, Massachusetts 01821, USA
| | | | - B Corzilius
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J J Walish
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M Rosay
- Bruker BioSpin, Billerica, Massachusetts 01821, USA
| | - W E Maas
- Bruker BioSpin, Billerica, Massachusetts 01821, USA
| | - M Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - S Vega
- Weizmann Institute of Science, Rehovot, Israel
| | - T M Swager
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - R G Griffin
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Kubicki DJ, Casano G, Schwarzwälder M, Abel S, Sauvée C, Ganesan K, Yulikov M, Rossini AJ, Jeschke G, Copéret C, Lesage A, Tordo P, Ouari O, Emsley L. Rational design of dinitroxide biradicals for efficient cross-effect dynamic nuclear polarization. Chem Sci 2015; 7:550-558. [PMID: 29896347 PMCID: PMC5952883 DOI: 10.1039/c5sc02921j] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/12/2015] [Indexed: 12/27/2022] Open
Abstract
A series of 37 dinitroxide biradicals have been prepared and their performance studied as polarizing agents in cross-effect DNP NMR experiments at 9.4 T and 100 K in 1,1,2,2-tetrachloroethane (TCE). We observe that in this regime the DNP performance is strongly correlated with the substituents on the polarizing agents, and electron and nuclear spin relaxation times, with longer relaxation times leading to better enhancements. We also observe that deuteration of the radicals generally leads to better DNP enhancement but with longer build-up time. One of the new radicals introduced here provides the best performance obtained so far under these conditions.
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Affiliation(s)
- Dominik J Kubicki
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
| | - Gilles Casano
- Aix-Marseille Université , CNRS , ICR UMR 7273 , 13397 Marseille , France . ;
| | - Martin Schwarzwälder
- ETH Zurich , Department of Chemistry, Laboratory of Inorganic Chemistry , 8093 Zurich , Switzerland
| | - Sébastien Abel
- Aix-Marseille Université , CNRS , ICR UMR 7273 , 13397 Marseille , France . ;
| | - Claire Sauvée
- Aix-Marseille Université , CNRS , ICR UMR 7273 , 13397 Marseille , France . ;
| | - Karthikeyan Ganesan
- Aix-Marseille Université , CNRS , ICR UMR 7273 , 13397 Marseille , France . ;
| | - Maxim Yulikov
- ETH Zurich , Department of Chemistry, Laboratory of Inorganic Chemistry , 8093 Zurich , Switzerland
| | - Aaron J Rossini
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
| | - Gunnar Jeschke
- ETH Zurich , Department of Chemistry, Laboratory of Inorganic Chemistry , 8093 Zurich , Switzerland
| | - Christophe Copéret
- ETH Zurich , Department of Chemistry, Laboratory of Inorganic Chemistry , 8093 Zurich , Switzerland
| | - Anne Lesage
- Université de Lyon , Institut de Sciences Analytiques (CNRS / ENS de Lyon / UCB-Lyon 1) , Centre de RMN à Très Hauts Champs , 69100 Villeurbanne , France
| | - Paul Tordo
- Aix-Marseille Université , CNRS , ICR UMR 7273 , 13397 Marseille , France . ;
| | - Olivier Ouari
- Aix-Marseille Université , CNRS , ICR UMR 7273 , 13397 Marseille , France . ;
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
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Mentink-Vigier F, Akbey Ü, Oschkinat H, Vega S, Feintuch A. Theoretical aspects of Magic Angle Spinning - Dynamic Nuclear Polarization. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 258:102-20. [PMID: 26232770 DOI: 10.1016/j.jmr.2015.07.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 07/01/2015] [Accepted: 07/04/2015] [Indexed: 05/06/2023]
Abstract
Magic Angle Spinning (MAS) combined with Dynamic Nuclear Polarization (DNP) has been proven in recent years to be a very powerful method for increasing solid-state NMR signals. Since the advent of biradicals such as TOTAPOL to increase the nuclear polarization new classes of radicals, with larger molecular weight and/or different spin properties have been developed. These have led to unprecedented signal gain, with varying results for different experimental parameters, in particular the microwave irradiation strength, the static field, and the spinning frequency. Recently it has been demonstrated that sample spinning imposes DNP enhancement processes that differ from the active DNP mechanism in static samples as upon sample spinning the DNP enhancements are the results of energy level anticrossings occurring periodically during each rotor cycle. In this work we present experimental results with regards to the MAS frequency dependence of the DNP enhancement profiles of four nitroxide-based radicals at two different sets of temperature, 110 and 160K. In fact, different magnitudes of reduction in enhancement are observed with increasing spinning frequency. Our simulation code for calculating MAS-DNP powder enhancements of small model spin systems has been improved to extend our studies of the influence of the interaction and relaxation parameters on powder enhancements. To achieve a better understanding we simulated the spin dynamics of a single three-spin system {ea-eb-n} during its steady state rotor periods and used the Landau-Zener formula to characterize the influence of the different anti-crossings on the polarizations of the system and their necessary action for reaching steady state conditions together with spin relaxation processes. Based on these model calculations we demonstrate that the maximum steady state nuclear polarization cannot become larger than the maximum polarization difference between the two electrons during the steady state rotor cycle. This study also shows the complexity of the MAS-DNP process and therefore the necessity to rely on numerical simulations for understanding parametric dependencies of the enhancements. Finally an extension of the spin system up to five spins allowed us to probe the first steps of the transfer of polarization from the nuclei coupled to the electrons to further away nuclei, demonstrating a decrease in the spin-diffusion barrier under MAS conditions.
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Affiliation(s)
| | - Ümit Akbey
- Leibniz-Institut für Molekulare Pharmakologie (FMP), NMR Supported Structural Biology, Robert Roessle Str. 10, 13125 Berlin, Germany; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Høegh-Guldbergs Gade 6B, Building: 1630, Room: 106, 8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Hartmut Oschkinat
- Leibniz-Institut für Molekulare Pharmakologie (FMP), NMR Supported Structural Biology, Robert Roessle Str. 10, 13125 Berlin, Germany
| | - Shimon Vega
- Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Akiva Feintuch
- Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel
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38
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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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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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40
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Mance D, Gast P, Huber M, Baldus M, Ivanov KL. The magnetic field dependence of cross-effect dynamic nuclear polarization under magic angle spinning. J Chem Phys 2015; 142:234201. [DOI: 10.1063/1.4922219] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Deni Mance
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Peter Gast
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Konstantin L. Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia and Novosibirsk State University, Pirogova 2, Novosibirsk 63009, Russia
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41
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Shimon D, Hovav Y, Kaminker I, Feintuch A, Goldfarb D, Vega S. Simultaneous DNP enhancements of (1)H and (13)C nuclei: theory and experiments. Phys Chem Chem Phys 2015; 17:11868-83. [PMID: 25869779 DOI: 10.1039/c5cp00406c] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DNP on heteronuclear spin systems often results in interesting phenomena such as the polarization enhancement of one nucleus during MW irradiation at the "forbidden" transition frequencies of another nucleus or the polarization transfer between the nuclei without MW irradiation. In this work we discuss the spin dynamics in a four-spin model system of the form {ea-eb-((1)H,(13)C)}, with the Larmor frequencies ωa, ωb, ωH and ωC, by performing Liouville space simulations. This spin system exhibits the common (1)H solid effect (SE), (13)C cross effect (CE) and in addition high order CE-DNP enhancements. Here we show, in particular, the "proton shifted (13)C-CE" mechanism that results in (13)C polarization when the model system, at one of its (13)C-CE conditions, is excited by a MW field at the zero quantum or double quantum electron-proton transitions ωMW = ωa ± ωH and ωMW = ωb ± ωH. Furthermore, we introduce the "heteronuclear" CE mechanism that becomes efficient when the system is at one of its combined CE conditions |ωa - ωb| = |ωH ± ωC|. At these conditions, simulations of the four-spin system show polarization transfer processes between the nuclei, during and without MW irradiation, resembling the polarization exchange effects often discussed in the literature. To link the "microscopic" four-spin simulations to the experimental results we use DNP lineshape simulations based on "macroscopic" rate equations describing the electron and nuclear polarization dynamics in large spin systems. This approach is applied based on electron-electron double resonance (ELDOR) measurements that show strong (1)H-SE features outside the EPR frequency range. Simulated ELDOR spectra combined with the indirect (13)C-CE (iCE) mechanism, result in additional "proton shifted (13)C-CE" features that are similar to the experimental ones. These features are also observed experimentally in (13)C-DNP spectra of a sample containing 15 mM of trityl in a glass forming solution of (13)C-glycerol/H2O and are analyzed by calculating the basic (13)C-SE and (13)C-iCE shapes using simulated ELDOR spectra that were fitted to the experimental ones.
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Affiliation(s)
- Daphna Shimon
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
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42
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Bruch EM, Warner MT, Thomine S, Tabares LC, Un S. Pulse Electron Double Resonance Detected Multinuclear NMR Spectra of Distant and Low Sensitivity Nuclei and Its Application to the Structure of Mn(II) Centers in Organisms. J Phys Chem B 2015; 119:13515-23. [PMID: 25730710 DOI: 10.1021/acs.jpcb.5b01624] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The ability to characterize the structure of metal centers beyond their primary ligands is important to understanding their chemistry. High-magnetic-field pulsed electron double resonance detected NMR (ELDOR-NMR) is shown to be a very sensitive approach to measuring the multinuclear NMR spectra of the nuclei surrounding Mn(II) ions. Resolved spectra of intact organisms with resonances arising from (55)Mn, (31)P, (1)H, (39)K, (35)Cl, (23)Na, and (14)N nuclei surrounding Mn(2+) centers were obtained. Naturally abundant cellular (13)C could be routinely measured as well. The amplitudes of the (14)N and (2)H ELDOR-NMR spectra were found to be linearly dependent on the number of nuclei in the ligand sphere. The evolution of the Mn(II) ELDOR-NMR spectra as a function of excitation time was found to be best described by a saturation phenomenon rather than a coherently driven process. Mn(II) ELDOR-NMR revealed details about not only the immediate ligands to the Mn(II) ions but also more distant nuclei, providing a view of their extended structures. This will be important for understanding the speciation and chemistry of the manganese complexes as well as other metals found in organisms.
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Affiliation(s)
- Eduardo M Bruch
- Service de Bioénergétique, Biologie Structurale et Mécanismes (CNRS UMR-8221), Institut de Biologie et de Technologies de Saclay, CEA-Saclay , F-91191 Gif-sur-Yvette, France
| | - Melissa T Warner
- Service de Bioénergétique, Biologie Structurale et Mécanismes (CNRS UMR-8221), Institut de Biologie et de Technologies de Saclay, CEA-Saclay , F-91191 Gif-sur-Yvette, France.,Department of Biology, Tufts University , Medford, Massachusetts 02155, United States
| | - Sébastien Thomine
- Institute for Integrative Biology of the Cell (I2BC), Saclay Plant Sciences, Université Paris-Saclay, CEA, CNRS, Université Paris-Sud , Gif-sur-Yvette, F-91198 France
| | - Leandro C Tabares
- Service de Bioénergétique, Biologie Structurale et Mécanismes (CNRS UMR-8221), Institut de Biologie et de Technologies de Saclay, CEA-Saclay , F-91191 Gif-sur-Yvette, France
| | - Sun Un
- Service de Bioénergétique, Biologie Structurale et Mécanismes (CNRS UMR-8221), Institut de Biologie et de Technologies de Saclay, CEA-Saclay , F-91191 Gif-sur-Yvette, France
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43
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Flori A, Liserani M, Bowen S, Ardenkjaer-Larsen JH, Menichetti L. Dissolution dynamic nuclear polarization of non-self-glassing agents: spectroscopy and relaxation of hyperpolarized [1-13C]acetate. J Phys Chem A 2015; 119:1885-93. [PMID: 25686013 DOI: 10.1021/jp511972g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The intrinsic physicochemical properties of the sample formulation are the key factors for efficient hyperpolarization through dissolution dynamic nuclear polarization (dissolution-DNP). We provide a comprehensive characterization of the DNP process for Na-[1-(13)C]acetate selected as a model for non-self-glassing agents: the solid-state polarization dynamics of different formulations and the effect of the paramagnetic agent (trityl radical) on the pattern of polarization and the relaxation profile were extensively analyzed. We quantified the effects of the glassing agent and Gd(3+)-chelate on DNP performance. The results reported here describe the constraints of the acetate formulation useful for future studies in this field with non-self-glassing enriched molecules.
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Affiliation(s)
- Alessandra Flori
- Fondazione CNR/Regione Toscana G. Monasterio, Pisa, I-56124, Italy
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44
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Hovav Y, Shimon D, Kaminker I, Feintuch A, Goldfarb D, Vega S. Effects of the electron polarization on dynamic nuclear polarization in solids. Phys Chem Chem Phys 2015; 17:6053-65. [DOI: 10.1039/c4cp05625f] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of the electron polarization distribution on the DNP line-shapes: theory and a demonstration on a 40 mM TEMPOL sample.
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Affiliation(s)
- Y. Hovav
- Weizmann institute of Science
- Rehovot
- Israel
| | - D. Shimon
- Weizmann institute of Science
- Rehovot
- Israel
| | | | | | | | - S. Vega
- Weizmann institute of Science
- Rehovot
- Israel
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45
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Ravera E, Shimon D, Feintuch A, Goldfarb D, Vega S, Flori A, Luchinat C, Menichetti L, Parigi G. The effect of Gd on trityl-based dynamic nuclear polarisation in solids. Phys Chem Chem Phys 2015; 17:26969-78. [DOI: 10.1039/c5cp04138d] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The increase in 13C polarisation of 13C-urea dissolved in samples containing water/DMSO mixtures and trityl radical (OX063) in the presence of Gd3+ is explained by changes in electron relaxation, electron spectral diffusion and effective electron–proton hyperfine interaction.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) and Department of Chemistry “Ugo Schiff”
- University of Florence
- Italy
| | - Daphna Shimon
- Chemical Physics Department
- Weizmann Institute of Science
- Rehovot
- Israel
| | - Akiva Feintuch
- Chemical Physics Department
- Weizmann Institute of Science
- Rehovot
- Israel
| | - Daniella Goldfarb
- Chemical Physics Department
- Weizmann Institute of Science
- Rehovot
- Israel
| | - Shimon Vega
- Chemical Physics Department
- Weizmann Institute of Science
- Rehovot
- Israel
| | - Alessandra Flori
- Fondazione CNR/Regione Toscana G. Monasterio and Institute of Life Sciences
- Scuola Superiore Sant'Anna
- Pisa
- Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Department of Chemistry “Ugo Schiff”
- University of Florence
- Italy
| | - Luca Menichetti
- Fondazione CNR/Regione Toscana G. Monasterio and Institute of Clinical Physiology
- National Council of Research
- Pisa
- Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) and Department of Chemistry “Ugo Schiff”
- University of Florence
- Italy
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46
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Hovav Y, Kaminker I, Shimon D, Feintuch A, Goldfarb D, Vega S. The electron depolarization during dynamic nuclear polarization: measurements and simulations. Phys Chem Chem Phys 2015; 17:226-44. [DOI: 10.1039/c4cp03825h] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Measurements and simulations of the electron spin polarization along the EPR spectrum of TEMPOL and trityl radicals, under DNP conditions.
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Affiliation(s)
- Y. Hovav
- Weizmann Institute of Science
- Rehovot
- Israel
| | | | - D. Shimon
- Weizmann Institute of Science
- Rehovot
- Israel
| | | | | | - S. Vega
- Weizmann Institute of Science
- Rehovot
- Israel
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47
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Smith AN, Caporini MA, Fanucci GE, Long JR. A Method for Dynamic Nuclear Polarization Enhancement of Membrane Proteins. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201410249] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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48
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Smith AN, Caporini MA, Fanucci GE, Long JR. A method for dynamic nuclear polarization enhancement of membrane proteins. Angew Chem Int Ed Engl 2014; 54:1542-6. [PMID: 25504310 DOI: 10.1002/anie.201410249] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Indexed: 12/29/2022]
Abstract
Dynamic nuclear polarization (DNP) magic-angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy has the potential to enhance NMR signals by orders of magnitude and to enable NMR characterization of proteins which are inherently dilute, such as membrane proteins. In this work spin-labeled lipid molecules (SL-lipids), when used as polarizing agents, lead to large and relatively homogeneous DNP enhancements throughout the lipid bilayer and to an embedded lung surfactant mimetic peptide, KL4 . Specifically, DNP MAS ssNMR experiments at 600 MHz/395 GHz on KL4 reconstituted in liposomes containing SL-lipids reveal DNP enhancement values over two times larger for KL4 compared to liposome suspensions containing the biradical TOTAPOL. These findings suggest an alternative sample preparation strategy for DNP MAS ssNMR studies of lipid membranes and integral membrane proteins.
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Affiliation(s)
- Adam N Smith
- Department of Chemistry, University of Florida, 214 Leigh Hall Gainesville, FL 32611-7200 (USA)
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49
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Corzilius B, Michaelis VK, Penzel SA, Ravera E, Smith AA, Luchinat C, Griffin RG. Dynamic nuclear polarization of (1)H, (13)C, and (59)Co in a tris(ethylenediamine)cobalt(III) crystalline lattice doped with Cr(III). J Am Chem Soc 2014; 136:11716-27. [PMID: 25069794 PMCID: PMC4140501 DOI: 10.1021/ja5044374] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The study of inorganic crystalline materials by solid-state NMR spectroscopy is often complicated by the low sensitivity of heavy nuclei. However, these materials often contain or can be prepared with paramagnetic dopants without significantly affecting the structure of the crystalline host. Dynamic nuclear polarization (DNP) is generally capable of enhancing NMR signals by transferring the magnetization of unpaired electrons to the nuclei. Therefore, the NMR sensitivity in these paramagnetically doped crystals might be increased by DNP. In this paper we demonstrate the possibility of efficient DNP transfer in polycrystalline samples of [Co(en)3Cl3]2·NaCl·6H2O (en = ethylenediamine, C2H8N2) doped with Cr(III) in varying concentrations between 0.1 and 3 mol %. We demonstrate that (1)H, (13)C, and (59)Co can be polarized by irradiation of Cr(III) with 140 GHz microwaves at a magnetic field of 5 T. We further explain our findings on the basis of electron paramagnetic resonance spectroscopy of the Cr(III) site and analysis of its temperature-dependent zero-field splitting, as well as the dependence of the DNP enhancement factor on the external magnetic field and microwave power. This first demonstration of DNP transfer from one paramagnetic metal ion to its diamagnetic host metal ion will pave the way for future applications of DNP in paramagnetically doped materials or metalloproteins.
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Affiliation(s)
- Björn Corzilius
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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50
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Smith AA, Corzilius B, Haze O, Swager TM, Griffin RG. Observation of strongly forbidden solid effect dynamic nuclear polarization transitions via electron-electron double resonance detected NMR. J Chem Phys 2014; 139:214201. [PMID: 24320373 DOI: 10.1063/1.4832323] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present electron paramagnetic resonance experiments for which solid effect dynamic nuclear polarization transitions were observed indirectly via polarization loss on the electron. This use of indirect observation allows characterization of the dynamic nuclear polarization (DNP) process close to the electron. Frequency profiles of the electron-detected solid effect obtained using trityl radical showed intense saturation of the electron at the usual solid effect condition, which involves a single electron and nucleus. However, higher order solid effect transitions involving two, three, or four nuclei were also observed with surprising intensity, although these transitions did not lead to bulk nuclear polarization--suggesting that higher order transitions are important primarily in the transfer of polarization to nuclei nearby the electron. Similar results were obtained for the SA-BDPA radical where strong electron-nuclear couplings produced splittings in the spectrum of the indirectly observed solid effect conditions. Observation of high order solid effect transitions supports recent studies of the solid effect, and suggests that a multi-spin solid effect mechanism may play a major role in polarization transfer via DNP.
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Affiliation(s)
- Albert A Smith
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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