1
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Vaneeckhaute E, Bocquelet C, Bellier L, Le HN, Rougier N, Jegadeesan SA, Vinod-Kumar S, Mathies G, Veyre L, Thieuleux C, Melzi R, Banks D, Kempf J, Stern Q, Jannin S. Full optimization of dynamic nuclear polarization on a 1 tesla benchtop polarizer with hyperpolarizing solids. Phys Chem Chem Phys 2024; 26:22049-22061. [PMID: 39114945 PMCID: PMC11307143 DOI: 10.1039/d4cp02022g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024]
Abstract
Hyperpolarization by dissolution dynamic nuclear polarization (dDNP) provides the opportunity to dramatically increase the weak nuclear magnetic resonance (NMR) signal of liquid molecular targets using the high polarization of electron radicals. Unfortunately, the solution-state hyperpolarization can only be accessed once since freezing and melting of the hyperpolarized sample happen in an irreversible fashion. A way to expand the application horizon of dDNP can therefore be to find a recyclable DNP alternative. To pursue this ambitious goal, we recently introduced the concept of recyclable hyperpolarized flow (HypFlow) DNP where hyperpolarization happens in porous hyperpolarizing solids placed in a compact benchtop DNP polarizer at a magnetic field of 1 T and a temperature of 77 K. Here we aim to optimize the radical concentrations immobilized in hyperpolarizing solids with the objective of generating as much polarization as possible in a timeframe (<1 s) compatible with future recyclable DNP applications. To do so, the solid-state DNP enhancement factors, build-up rates and DNP spectra of different hyperpolarizing solids containing various nitroxide radical loadings (20-74 μmol cm-3) are compared against the DNP performance of varying nitroxide concentrations (10-100 mM) solvated in a glassy frozen solution. We demonstrate that in <1 s, polarization enhancement goes up to 56 and 102 with surface-bound and solvated radicals, respectively, under the optimized conditions. For the range of nitroxide concentrations used cross effect DNP seems to be the dominant mechanism under benchtop conditions. This was deduced from the electron paramagnetic resonance (EPR) lineshape of TEMPOL investigated using Q-band EPR measurements.
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Affiliation(s)
- Ewoud Vaneeckhaute
- Université Claude Bernard Lyon 1, CNRS, ENS Lyon, UCBL, CRMN UMR 5082, 69100 Villeurbanne, France.
| | - Charlotte Bocquelet
- Université Claude Bernard Lyon 1, CNRS, ENS Lyon, UCBL, CRMN UMR 5082, 69100 Villeurbanne, France.
| | - Léa Bellier
- Université Claude Bernard Lyon 1, CNRS, ENS Lyon, UCBL, CRMN UMR 5082, 69100 Villeurbanne, France.
| | - Huu-Nghia Le
- Université Claude Bernard Lyon 1, Institut de Chimie de Lyon, CP2M UMR 5128 CNRS-UCBL-CPE Lyon, 69616 Villeurbanne, France
| | - Nathan Rougier
- Université Claude Bernard Lyon 1, CNRS, ENS Lyon, UCBL, CRMN UMR 5082, 69100 Villeurbanne, France.
| | | | - Sanjay Vinod-Kumar
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, Germany
| | - Guinevere Mathies
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, Germany
| | - Laurent Veyre
- Université Claude Bernard Lyon 1, Institut de Chimie de Lyon, CP2M UMR 5128 CNRS-UCBL-CPE Lyon, 69616 Villeurbanne, France
| | - Chloe Thieuleux
- Université Claude Bernard Lyon 1, Institut de Chimie de Lyon, CP2M UMR 5128 CNRS-UCBL-CPE Lyon, 69616 Villeurbanne, France
| | - Roberto Melzi
- Bruker Italia S.r.l., Viale V. Lancetti 43, 20158 Milano, Italy
| | - Daniel Banks
- Bruker Biospin, Billerica, Massachusetts 01821, USA
| | - James Kempf
- Bruker Biospin, Billerica, Massachusetts 01821, USA
| | - Quentin Stern
- Université Claude Bernard Lyon 1, CNRS, ENS Lyon, UCBL, CRMN UMR 5082, 69100 Villeurbanne, France.
| | - Sami Jannin
- Université Claude Bernard Lyon 1, CNRS, ENS Lyon, UCBL, CRMN UMR 5082, 69100 Villeurbanne, France.
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2
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Millen M, Alaniva N, Saliba EP, Overall SA, Däpp A, Pagonakis IG, Sigurdsson ST, Björgvinsdóttir S, Barnes AB. Frequency-Chirped Magic Angle Spinning Dynamic Nuclear Polarization Combined with Electron Decoupling. J Phys Chem Lett 2024; 15:7228-7235. [PMID: 38975905 PMCID: PMC11261599 DOI: 10.1021/acs.jpclett.4c01075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/09/2024]
Abstract
Magic angle spinning (MAS) dynamic nuclear polarization (DNP) increases the signal intensity of solid-state nuclear magnetic resonance. DNP typically uses continuous wave (CW) microwave irradiation close to the resonance frequency of unpaired electron spins. In this study, we demonstrate that frequency-chirped microwaves improve DNP performance under MAS. By modulating the gyrotron anode potential, we generate a train of microwave chirps with a maximum bandwidth of 310 MHz and a maximum incident power on the spinning sample of 18 W. We characterize the efficiency of chirped DNP using the following polarizing agents: TEMTriPol-1, AsymPolPOK, AMUPol, and Finland trityl. The effects of different chirp widths and periods are analyzed at different MAS frequencies and microwave powers. Furthermore, we show that chirped DNP can be combined with electron decoupling to improve signal intensity by 59%, compared to CW DNP without electron decoupling, using Finland trityl as a polarizing agent.
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Affiliation(s)
- Marthe Millen
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Nicholas Alaniva
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Edward P. Saliba
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Sarah A. Overall
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Alexander Däpp
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Ioannis Gr. Pagonakis
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | | | - Snædís Björgvinsdóttir
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Alexander B. Barnes
- Institute
of Molecular Physical Science, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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3
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Equbal A, Ramanathan C, Han S. Dipolar Order Induced Electron Spin Hyperpolarization. J Phys Chem Lett 2024; 15:5397-5406. [PMID: 38739470 PMCID: PMC11129302 DOI: 10.1021/acs.jpclett.4c00294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 05/16/2024]
Abstract
The structure of coupled electron spin systems is of fundamental interest to many applications, including dynamic nuclear polarization (DNP), enhanced nuclear magnetic resonance (NMR), the generation of electron spin qubits for quantum information science (QIS), and quantitative studies of paramagnetic systems by electron paramagnetic resonance (EPR). However, the characterization of electron spin coupling networks is nontrivial, especially at high magnetic fields. This study focuses on a system containing high concentrations of trityl radicals that give rise to a DNP enhancement profile of 1H NMR characteristic of the presence of electron spin clusters. When this system is subject to selective microwave saturation through pump-probe ELectron DOuble Resonance (ELDOR) experiments, electron spin hyperpolarization is observed. We show that the generation of an out-of-equilibrium longitudinal dipolar order is responsible for the transient hyperpolarization of electron spins. Notably, the coupled electron spin system needs to form an AX-like system (where the difference in the Zeeman interactions of two spins is larger than their coupling interaction) such that selective microwave irradiation can generate signatures of electron spin hyperpolarization. We show that the extent of dipolar order, as manifested in the extent of electron spin hyperpolarization generated, can be altered by tuning the pump or probe pulse length, or the interpulse delay in ELDOR experiments that change the efficiency to generate or readout longitudinal dipolar order. Pump-probe ELDOR with selective saturation is an effective means for characterizing coupled electron spins forming AX-type spin systems that are foundational for DNP and quantum sensing.
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Affiliation(s)
- Asif Equbal
- Department
of Chemistry, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
- Center
for Quantum and Topological Systems, New
York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Chandrasekhar Ramanathan
- Department
of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Songi Han
- Department
of Chemistry and Biochemistry, University
of California, Santa Barbara, Santa
Barbara, California 93106, United States
- Department
of Chemical Engineering, University of California,
Santa Barbara, Santa Barbara, California 93106, United States
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4
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Epasto LM, Maimbourg T, Rosso A, Kurzbach D. Unified understanding of the breakdown of thermal mixing dynamic nuclear polarization: The role of temperature and radical concentration. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 362:107670. [PMID: 38603922 DOI: 10.1016/j.jmr.2024.107670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 04/13/2024]
Abstract
We reveal an interplay between temperature and radical concentration necessary to establish thermal mixing (TM) as an efficient dynamic nuclear polarization (DNP) mechanism. We conducted DNP experiments by hyperpolarizing widely used DNP samples, i.e., sodium pyruvate-1-13C in water/glycerol mixtures at varying nitroxide radical (TEMPOL) concentrations and microwave irradiation frequencies, measuring proton and carbon-13 spin temperatures. Using a cryogen consumption-free prototype-DNP apparatus, we could probe cryogenic temperatures between 1.5 and 6.5 K, i.e., below and above the boiling point of liquid helium. We identify two mechanisms for the breakdown of TM: (i) Anderson type of quantum localization for low radical concentration, or (ii) quantum Zeno localization occurring at high temperature. This observation allowed us to reconcile the recent diverging observations regarding the relevance of TM as a DNP mechanism by proposing a unifying picture and, consequently, to find a trade-off between radical concentration and electron relaxation times, which offers a pathway to improve experimental DNP performance based on TM.
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Affiliation(s)
- Ludovica M Epasto
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090, Vienna, Austria; University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, 1090, Vienna, Austria
| | - Thibaud Maimbourg
- Université Paris-Saclay, CNRS, CEA, Institut de physique théorique, 91191, Gif-sur-Yvette, France
| | - Alberto Rosso
- Université Paris-Saclay, CNRS, LPTMS, 91405, Orsay, France.
| | - Dennis Kurzbach
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090, Vienna, Austria; University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, 1090, Vienna, Austria.
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5
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von Witte G, Himmler A, Kozerke S, Ernst M. Relaxation enhancement by microwave irradiation may limit dynamic nuclear polarization. Phys Chem Chem Phys 2024; 26:9578-9585. [PMID: 38462920 PMCID: PMC10954235 DOI: 10.1039/d3cp06025j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 02/07/2024] [Indexed: 03/12/2024]
Abstract
Dynamic nuclear polarization enables the hyperpolarization of nuclear spins beyond the thermal-equilibrium Boltzmann distribution. However, it is often unclear why the experimentally measured hyperpolarization is below the theoretically achievable maximum polarization. We report a (near-) resonant relaxation enhancement by microwave (MW) irradiation, leading to a significant increase in the nuclear polarization decay compared to measurements without MW irradiation. For example, the increased nuclear relaxation limits the achievable polarization levels to around 35% instead of hypothetical 60%, measured in the DNP material TEMPO in 1H glassy matrices at 3.3 K and 7 T. Applying rate-equation models to published build-up and decay data indicates that such relaxation enhancement is a common issue in many samples when using different radicals at low sample temperatures and high Boltzmann polarizations of the electrons. Accordingly, quantification and a better understanding of the relaxation processes under MW irradiation might help to design samples and processes towards achieving higher nuclear hyperpolarization levels.
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Affiliation(s)
- Gevin von Witte
- Institute for Biomedical Engineering, University and ETH Zurich, 8092 Zurich, Switzerland
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
| | - Aaron Himmler
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Matthias Ernst
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
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6
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Nir-Arad O, Shlomi DH, Israelstam A, Amit T, Manukovsky N, Fialkov AB, Kaminker I. The CW-EPR Capabilities of a Dual DNP/EPR Spectrometer Operating at 14 and 7 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 360:107635. [PMID: 38401475 DOI: 10.1016/j.jmr.2024.107635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 12/24/2023] [Accepted: 02/07/2024] [Indexed: 02/26/2024]
Abstract
High-field electron paramagnetic resonance (EPR) measurements are indispensable for a better understanding of dynamic nuclear polarization (DNP), which relies on polarization transfer between electron and nuclear spins. DNP experiments are typically performed at high > 7 T magnetic fields and low ≤ 100 K temperatures, while EPR instrumentation capable of EPR measurements under these conditions is scarce. In this paper, we describe the CW EPR capabilities of a dual DNP/EPR spectrometer that is designed to carry out EPR experiments under "DNP conditions" at 14 and 7 T. In the first part, we present the design of this instrument, highlighting the choices made to allow for both DNP and EPR operations. The spectrometer uses a sweepable cryogen-free magnet with NMR-grade homogeneity, a closed-cycle cooling system, a quasi-optical induction mode bridge, and a superheterodyne receiver system. The probe design is optimized for low heat load and fast sample exchange under cryogenic conditions. The spectrometer can operate in frequency and field sweep modes, including wide field sweeps using the main coil of the magnet. In the second part, we present EPR spectra acquired over a wide range of samples and operating conditions, illustrating the CW EPR capabilities of the instrument.
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Affiliation(s)
- Orit Nir-Arad
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - David H Shlomi
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Amit Israelstam
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tomer Amit
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Nurit Manukovsky
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Alexander B Fialkov
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ilia Kaminker
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
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7
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Li S, Bhattacharya S, Chou CY, Chu M, Chou SC, Tonelli M, Goger M, Yang H, Palmer AG, Cavagnero S. LC-Photo-CIDNP hyperpolarization of biomolecules bearing a quasi-isolated spin pair: Magnetic-Field dependence via a rapid-shuttling device. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 359:107616. [PMID: 38271744 PMCID: PMC10922348 DOI: 10.1016/j.jmr.2023.107616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/27/2024]
Abstract
Liquid-state low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) is an emerging technology tailored to enhance the sensitivity of NMR spectroscopy via LED- or laser-mediated optical irradiation. LC-photo-CIDNP is particularly useful to detect solvent-exposed aromatic residues (Trp, Tyr), either in isolation or within polypeptides and proteins. This study investigates the magnetic-field dependence of the LC-photo-CIDNP of Trp-α-13C-β,β,2,4,5,6,7-d7, a Trp isotopolog bearing a quasi-isolated 1Hα-13Cαspin pair (QISP). We employed a new rapid-shuttling side-illumination field-cycling device that enables ultra-fast (90-120 ms) vertical movements of NMR samples within the bore of a superconducting magnet. Thus, LC-photo-CIDNP hyperpolarization occurs at low field, while hyperpolarized signals are detected at high field (700 MHz). Resonance lineshapes were excellent, and the effect of several fields (1.18-7.08 T range) on hyperpolarization efficiency could be readily explored. Remarkably, unprecedented LC-photo-CIDNP enhancements ε ≅ 1,200 were obtained at 50 MHz (1.18 T), suggesting exciting avenues to hypersensitive LED-enhanced NMR in liquids at low field.
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Affiliation(s)
- Siyu Li
- Dept. of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | | | - Ching-Yu Chou
- Field Cycling Technology LTD., New Taipei City 23444, Taiwan, ROC
| | - Minglee Chu
- Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan, ROC
| | - Shu-Cheng Chou
- Field Cycling Technology LTD., New Taipei City 23444, Taiwan, ROC
| | - Marco Tonelli
- Dept. of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Michael Goger
- New York Structural Biology Center, New York, NY 10027, United States
| | - Hanming Yang
- Dept. of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Arthur G Palmer
- New York Structural Biology Center, New York, NY 10027, United States; Dept. of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, United States
| | - Silvia Cavagnero
- Dept. of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States.
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8
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von Witte G, Ernst M, Kozerke S. Modelling and correcting the impact of RF pulses for continuous monitoring of hyperpolarized NMR. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2023; 4:175-186. [PMID: 37904858 PMCID: PMC10583294 DOI: 10.5194/mr-4-175-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/06/2023] [Indexed: 11/01/2023]
Abstract
Monitoring the build-up or decay of hyperpolarization in nuclear magnetic resonance requires radio-frequency (RF) pulses to generate observable nuclear magnetization. However, the pulses also lead to a depletion of the polarization and, thus, alter the spin dynamics. To simulate the effects of RF pulses on the polarization build-up and decay, we propose a first-order rate-equation model describing the dynamics of the hyperpolarization process through a single source and a relaxation term. The model offers a direct interpretation of the measured steady-state polarization and build-up time constant. Furthermore, the rate-equation model is used to study three different methods to correct the errors introduced by RF pulses: (i) a 1 / cos n - 1 θ correction (θ denoting the RF pulse flip angle), which is only applicable to decays; (ii) an analytical model introduced previously in the literature; and (iii) an iterative correction approach proposed here. The three correction methods are compared using simulated data for a range of RF flip angles and RF repetition times. The correction methods are also tested on experimental data obtained with dynamic nuclear polarization (DNP) using 4-oxo-TEMPO in 1 H glassy matrices. It is demonstrated that the analytical and iterative corrections allow us to obtain accurate build-up times and steady-state polarizations (enhancements) for RF flip angles of up to 25∘ during the polarization build-up process within ± 10 % error when compared to data acquired with small RF flip angles (< 3 ∘ ). For polarization decay experiments, corrections are shown to be accurate for RF flip angles of up to 12∘ . In conclusion, the proposed iterative correction allows us to compensate for the impact of RF pulses offering an accurate estimation of polarization levels, build-up and decay time constants in hyperpolarization experiments.
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Affiliation(s)
- Gevin von Witte
- Institute for Biomedical Engineering, University and ETH Zurich, 8092 Zurich, Switzerland
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Matthias Ernst
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, 8092 Zurich, Switzerland
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9
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Himmler A, Albannay MM, von Witte G, Kozerke S, Ernst M. Electroplated waveguides to enhance DNP and EPR spectra of silicon and diamond particles. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2022; 3:203-209. [PMID: 37904872 PMCID: PMC10539804 DOI: 10.5194/mr-3-203-2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/20/2022] [Indexed: 11/01/2023]
Abstract
Electroplating the waveguide of a 7 T polarizer in a simple innovative way increased microwave power delivered to the sample by 3.1 dB. Silicon particles, while interesting for hyperpolarized MRI applications, are challenging to polarize due to inefficient microwave multipliers at the electron Larmor frequency at high magnetic fields and fast electronic relaxation times. Improving microwave transmission directly translates to more efficient EPR excitation at high-field, low-temperature conditions and promises faster and higher 29 Si polarization buildup through dynamic nuclear polarization (DNP).
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Affiliation(s)
- Aaron Himmler
- ETH Zurich, Laboratory of Physical Chemistry, Zurich 8093,
Switzerland
| | - Mohammed M. Albannay
- ETH Zurich, Laboratory of Physical Chemistry, Zurich 8093,
Switzerland
- University and ETH Zurich, Institute for Biomedical Engineering,
Zurich 8092, Switzerland
| | - Gevin von Witte
- ETH Zurich, Laboratory of Physical Chemistry, Zurich 8093,
Switzerland
- University and ETH Zurich, Institute for Biomedical Engineering,
Zurich 8092, Switzerland
| | - Sebastian Kozerke
- University and ETH Zurich, Institute for Biomedical Engineering,
Zurich 8092, Switzerland
| | - Matthias Ernst
- ETH Zurich, Laboratory of Physical Chemistry, Zurich 8093,
Switzerland
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10
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Dey A, Charrier B, Lemaitre K, Ribay V, Eshchenko D, Schnell M, Melzi R, Stern Q, Cousin S, Kempf J, Jannin S, Dumez JN, Giraudeau P. Fine optimization of a dissolution dynamic nuclear polarization experimental setting for 13C NMR of metabolic samples. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2022; 3:183-202. [PMID: 37904870 PMCID: PMC10583282 DOI: 10.5194/mr-3-183-2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/16/2022] [Indexed: 11/01/2023]
Abstract
NMR-based analysis of metabolite mixtures provides crucial information on biological systems but mostly relies on 1D 1 H experiments for maximizing sensitivity. However, strong peak overlap of 1 H spectra often is a limitation for the analysis of inherently complex biological mixtures. Dissolution dynamic nuclear polarization (d-DNP) improves NMR sensitivity by several orders of magnitude, which enables 13 C NMR-based analysis of metabolites at natural abundance. We have recently demonstrated the successful introduction of d-DNP into a full untargeted metabolomics workflow applied to the study of plant metabolism. Here we describe the systematic optimization of d-DNP experimental settings for experiments at natural 13 C abundance and show how the resolution, sensitivity, and ultimately the number of detectable signals improve as a result. We have systematically optimized the parameters involved (in a semi-automated prototype d-DNP system, from sample preparation to signal detection, aiming at providing an optimization guide for potential users of such a system, who may not be experts in instrumental development). The optimization procedure makes it possible to detect previously inaccessible protonated 13 C signals of metabolites at natural abundance with at least 4 times improved line shape and a high repeatability compared to a previously reported d-DNP-enhanced untargeted metabolomic study. This extends the application scope of hyperpolarized 13 C NMR at natural abundance and paves the way to a more general use of DNP-hyperpolarized NMR in metabolomics studies.
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Affiliation(s)
- Arnab Dey
- Nantes Université, CNRS, CEISAM UMR 6230, 44000 Nantes, France
| | - Benoît Charrier
- Nantes Université, CNRS, CEISAM UMR 6230, 44000 Nantes, France
| | - Karine Lemaitre
- Nantes Université, CNRS, CEISAM UMR 6230, 44000 Nantes, France
| | - Victor Ribay
- Nantes Université, CNRS, CEISAM UMR 6230, 44000 Nantes, France
| | - Dmitry Eshchenko
- Bruker Biospin, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Marc Schnell
- Bruker Biospin, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Roberto Melzi
- Bruker Biospin, Viale V. Lancetti 43, 20158 Milan, Italy
| | - Quentin Stern
- Université de Lyon, CNRS, Université Claude Bernard Lyon 1,
ENS de Lyon, Centre de RMN à Très Hauts Champs (CRMN), UMR5082,
69100 Villeurbanne, France
| | | | | | - Sami Jannin
- Université de Lyon, CNRS, Université Claude Bernard Lyon 1,
ENS de Lyon, Centre de RMN à Très Hauts Champs (CRMN), UMR5082,
69100 Villeurbanne, France
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11
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Yang H, Li S, Mickles CA, Guzman-Luna V, Sugisaki K, Thompson CM, Dang HH, Cavagnero S. Selective Isotope Labeling and LC-Photo-CIDNP Enable NMR Spectroscopy at Low-Nanomolar Concentration. J Am Chem Soc 2022; 144:11608-11619. [PMID: 35700317 DOI: 10.1021/jacs.2c01809] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
NMR spectroscopy is a powerful tool to investigate molecular structure and dynamics. The poor sensitivity of this technique, however, limits its ability to tackle questions requiring dilute samples. Low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) is an optically enhanced NMR technology capable of addressing the above challenge by increasing the detection limit of aromatic amino acids in solution up to 1000-fold, either in isolation or within proteins. Here, we show that the absence of NMR-active nuclei close to a magnetically active site of interest (e.g., the structurally diagnostic 1Hα-13Cα pair of amino acids) is expected to significantly increase LC-photo-CIDNP hyperpolarization. Then, we exploit the spin-diluted tryptophan isotopolog Trp-α-13C-β,β,2,4,5,6,7-d7 and take advantage of the above prediction to experimentally achieve a ca 4-fold enhancement in NMR sensitivity over regular LC-photo-CIDNP. This advance enables the rapid (within seconds) detection of 20 nM concentrations or the molecule of interest, corresponding to a remarkable 3 ng detection limit. Finally, the above Trp isotopolog is amenable to incorporation within proteins and is readily detectable at a 1 μM concentration in complex cell-like media, including Escherichia coli cell-free extracts.
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Affiliation(s)
- Hanming Yang
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Siyu Li
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Clayton A Mickles
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Valeria Guzman-Luna
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kenji Sugisaki
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.,JST PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Clayton M Thompson
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Hung H Dang
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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12
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Equbal A, Jain SK, Li Y, Tagami K, Wang X, Han S. Role of electron spin dynamics and coupling network in designing dynamic nuclear polarization. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 126-127:1-16. [PMID: 34852921 DOI: 10.1016/j.pnmrs.2021.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/22/2021] [Indexed: 06/13/2023]
Abstract
Dynamic nuclear polarization (DNP) has emerged as a powerful sensitivity booster of nuclear magnetic resonance (NMR) spectroscopy for the characterization of biological solids, catalysts and other functional materials, but is yet to reach its full potential. DNP transfers the high polarization of electron spins to nuclear spins using microwave irradiation as a perturbation. A major focus in DNP research is to improve its efficiency at conditions germane to solid-state NMR, at high magnetic fields and fast magic-angle spinning. In this review, we highlight three key strategies towards designing DNP experiments: time-domain "smart" microwave manipulation to optimize and/or modulate electron spin polarization, EPR detection under operational DNP conditions to decipher the underlying electron spin dynamics, and quantum mechanical simulations of coupled electron spins to gain microscopic insights into the DNP mechanism. These strategies are aimed at understanding and modeling the properties of the electron spin dynamics and coupling network. The outcome of these strategies is expected to be key to developing next-generation polarizing agents and DNP methods.
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Affiliation(s)
- Asif Equbal
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Sheetal Kumar Jain
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Yuanxin Li
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Kan Tagami
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Xiaoling Wang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, United States; Department of Physics, 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; Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, United States.
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13
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Aghelnejad B, Marhabaie S, Baudin M, Bodenhausen G, Carnevale D. Spin Thermometry: A Straightforward Measure of Millikelvin Deuterium Spin Temperatures Achieved by Dynamic Nuclear Polarization. J Phys Chem Lett 2020; 11:3219-3225. [PMID: 32251593 DOI: 10.1021/acs.jpclett.0c00713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dynamic nuclear polarization of samples at low temperatures, typically between 1.2 and 4.2 K, allows one to achieve spin temperatures of as low as 2 mK so that for many nuclear isotopes the high-temperature approximation is violated for the nuclear Zeeman interaction. This leads to characteristic asymmetries in powder spectra. We show that the line shapes due to the quadrupolar couplings of deuterium spins present in virtually all solvents used for such experiments (DNP juice) allow the quick yet accurate determination of the deuterium spin temperature or, equivalently, the deuterium polarization. The observation of quadrupolar echoes excited by small flip-angle pulses allows one to monitor the build-up and decay of the positive or negative deuterium polarization.
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Affiliation(s)
- Behdad Aghelnejad
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
- Bruker Biospin SAS, F-67160 Wissembourg, France
| | - Sina Marhabaie
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
- IFSTTAR, Université Paris-Est, UPEMLV, Marne-la-Vallée, France
| | - Mathieu Baudin
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
- Laboratoire de Chimie et Biologie Pharmacologiques et Toxicologiques, Université de Paris, CNRS UMR 8601, Université Paris Descartes, 45 rue des Saints Pères, 75006 Paris, France
| | - Geoffrey Bodenhausen
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Diego Carnevale
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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14
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Equbal A, Li Y, Tabassum T, Han S. Crossover from a Solid Effect to Thermal Mixing 1H Dynamic Nuclear Polarization with Trityl-OX063. J Phys Chem Lett 2020; 11:3718-3723. [PMID: 32315195 DOI: 10.1021/acs.jpclett.0c00830] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Trityl-OX063 is a narrow-line, water-soluble, and biocompatible polarizing agent, widely used for dynamic nuclear polarization (DNP) amplified NMR of 13C, but not of the abundant 1H nuclear spin, for which the ineffective solid effect (SE) is expected to be operational. Surprisingly, we observed a crossover from SE to thermal mixing (TM) DNP of 1H with increasing Trityl-OX063 concentration at 7 T. We experimentally ascertained diagnostic signatures of TM-DNP that have only been theoretically predicted: (i) an electron paramagnetic resonance (EPR) spectrum that maintains an asymmetrically broadened EPR line from strong e-e couplings and (ii) hyperpolarization, i.e., cooling of select electron-spin populations, manifested in a characteristic pump-probe electron double-resonance spectrum under DNP conditions. Low microwave power requirements, high polarization transfer rates, and efficient DNP at high magnetic fields are the key benefits of TM-DNP.
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Affiliation(s)
- Asif Equbal
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Yuanxin Li
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Tarnuma Tabassum
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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