1
|
Camenisch GM, Wili N, Jeschke G, Ernst M. Pulsed dynamic nuclear polarization: a comprehensive Floquet description. Phys Chem Chem Phys 2024; 26:17666-17683. [PMID: 38868989 PMCID: PMC11202326 DOI: 10.1039/d4cp01788a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/05/2024] [Indexed: 06/14/2024]
Abstract
Dynamic nuclear polarization (DNP) experiments using microwave (mw) pulse sequences are one approach to transfer the larger polarization on the electron spin to nuclear spins of interest. How the result of such experiments depends on the external magnetic field and the excitation power is part of an ongoing debate and of paramount importance for applications that require high chemical-shift resolution. To date numerical simulations using operator-based Floquet theory have been used to predict and explain experimental data. However, such numerical simulations provide only limited insight into parameters relevant for efficient polarization transfer, such as transition amplitudes or resonance offsets. Here we present an alternative method to describe pulsed DNP experiments by using matrix-based Floquet theory. This approach leads to analytical expressions for the transition amplitudes and resonance offsets. We validate the method by comparing computations by these analytical expressions to their numerical counterparts and to experimental results for the XiX, TOP and TPPM DNP sequences. Our results explain the experimental data and are in very good agreement with the numerical simulations. The analytical expressions allow for the discussion of the scaling behaviour of pulsed DNP experiments with respect to the external magnetic field. We find that the transition amplitudes scale inversely with the external magnetic field.
Collapse
Affiliation(s)
- Gian-Marco Camenisch
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
| | - Nino Wili
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Aarhus, Denmark
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
| | - Matthias Ernst
- Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Tobar C, Albanese K, Chaklashiya R, Equbal A, Hawker C, Han S. Multi Electron Spin Cluster Enabled Dynamic Nuclear Polarization with Sulfonated BDPA. J Phys Chem Lett 2023; 14:11640-11650. [PMID: 38108283 DOI: 10.1021/acs.jpclett.3c02428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Dynamic nuclear polarization (DNP) can amplify the solid-state nuclear magnetic resonance (NMR) signal by several orders of magnitude. The mechanism of DNP utilizing α,γ-bisdiphenylene-β-phenylallyl (BDPA) variants as Polarizing Agents (PA) has been the subject of lively discussions on account of their remarkable DNP efficiency with low demand for microwave power. We propose that electron spin clustering of sulfonated BDPA is responsible for its DNP performance, as revealed by the temperature-dependent shape of the central DNP profile and strong electron-electron (e-e) crosstalk seen by Electron Double Resonance. We demonstrate that a multielectron spin cluster can be modeled with three coupled spins, where electron J (exchange) coupling between one of the e-e pairs matching the NMR Larmor frequency induces the experimentally observed absorptive central DNP profile, and the electron T1e modulated by temperature and magic-angle spinning alters the shape between an absorptive and dispersive feature. Understanding the microscopic origin is key to designing new PAs to harness the microwave-power-efficient DNP effect observed with BDPA variants.
Collapse
Affiliation(s)
- Celeste Tobar
- Department of Chemistry and Biochemistry, University of California, Santa Barbara 93106, California, United States
| | - Kaitlin Albanese
- Materials Department, University of California, Santa Barbara 93106, California, United States
| | - Raj Chaklashiya
- Materials Department, University of California, Santa Barbara 93106, California, United States
| | - Asif Equbal
- Department of Chemistry, NYU Abu Dhabi, Saadiyat Campus, PO Box 129188, Abu Dhabi 00000, United Arab Emirates
| | - Craig Hawker
- Materials Department, University of California, Santa Barbara 93106, California, United States
| | - Songi Han
- Department of Chemistry, Northwestern University, Evanston 60208, Illinois, United States
| |
Collapse
|
4
|
Peters JP, Brahms A, Janicaud V, Anikeeva M, Peschke E, Ellermann F, Ferrari A, Hellmold D, Held-Feindt J, Kim NM, Meiser J, Aden K, Herges R, Hövener JB, Pravdivtsev AN. Nitrogen-15 dynamic nuclear polarization of nicotinamide derivatives in biocompatible solutions. SCIENCE ADVANCES 2023; 9:eadd3643. [PMID: 37611105 PMCID: PMC10446501 DOI: 10.1126/sciadv.add3643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/21/2023] [Indexed: 08/25/2023]
Abstract
Dissolution dynamic nuclear polarization (dDNP) increases the sensitivity of magnetic resonance imaging by more than 10,000 times, enabling in vivo metabolic imaging to be performed noninvasively in real time. Here, we are developing a group of dDNP polarized tracers based on nicotinamide (NAM). We synthesized 1-15N-NAM and 1-15N nicotinic acid and hyperpolarized them with dDNP, reaching (13.0 ± 1.9)% 15N polarization. We found that the lifetime of hyperpolarized 1-15N-NAM is strongly field- and pH-dependent, with T1 being as long as 41 s at a pH of 12 and 1 T while as short as a few seconds at neutral pH and fields below 1 T. The remarkably short 1-15N lifetime at low magnetic fields and neutral pH drove us to establish a unique pH neutralization procedure. Using 15N dDNP and an inexpensive rodent imaging probe designed in-house, we acquired a 15N MRI of 1-15N-NAM (previously hyperpolarized for more than an hour) in less than 1 s.
Collapse
Affiliation(s)
- Josh P. Peters
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Arne Brahms
- Otto Diels Institute for Organic Chemistry, Kiel University, Otto-Hahn Platz 4, 24098 Kiel, Germany
| | - Vivian Janicaud
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Maria Anikeeva
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Eva Peschke
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Frowin Ellermann
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Arianna Ferrari
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Dana Hellmold
- Department of Neurosurgery, University Medical Center Kiel, Arnold-Heller-Str. 3, House D, 24105 Kiel, Germany
| | - Janka Held-Feindt
- Department of Neurosurgery, University Medical Center Kiel, Arnold-Heller-Str. 3, House D, 24105 Kiel, Germany
| | - Na-mi Kim
- Institute of Clinical Molecular Biology, Kiel University, Rosalind-Franklin-Straße 12, 24105 Kiel, Germany
| | - Johannes Meiser
- Cancer Metabolism Group, Department of Cancer Research, Luxembourg Institute of Health, 6A Rue Nicolas-Ernest Barblé, 1210 Luxembourg, Luxembourg
| | - Konrad Aden
- Institute of Clinical Molecular Biology, Kiel University, Rosalind-Franklin-Straße 12, 24105 Kiel, Germany
- Department of Internal Medicine I, University Medical Center Kiel, Kiel, Germany
| | - Rainer Herges
- Otto Diels Institute for Organic Chemistry, Kiel University, Otto-Hahn Platz 4, 24098 Kiel, Germany
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - Andrey N. Pravdivtsev
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Kiel, Kiel University, Am Botanischen Garten 14, 24118 Kiel, Germany
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Negroni M, Turhan E, Kress T, Ceillier M, Jannin S, Kurzbach D. Frémy's Salt as a Low-Persistence Hyperpolarization Agent: Efficient Dynamic Nuclear Polarization Plus Rapid Radical Scavenging. J Am Chem Soc 2022; 144:20680-20686. [PMID: 36322908 PMCID: PMC9673139 DOI: 10.1021/jacs.2c07960] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Indexed: 11/17/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a key technique for molecular structure determination in solution. However, due to its low sensitivity, many efforts have been made to improve signal strengths and reduce the required substrate amounts. In this regard, dissolution dynamic nuclear polarization (DDNP) is a versatile approach as signal enhancements of over 10 000-fold are achievable. Samples are signal-enhanced ex situ by transferring electronic polarization from radicals to nuclear spins before dissolving and shuttling the boosted sample to an NMR spectrometer for detection. However, the applicability of DDNP suffers from one major drawback, namely, paramagnetic relaxation enhancements (PREs) that critically reduce relaxation times due to the codissolved radicals. PREs are the primary source of polarization losses canceling the signal improvements obtained by DNP. We solve this problem by using potassium nitrosodisulfonate (Frémy's salt) as polarization agent (PA), which provides high nuclear spin polarization and allows for rapid scavenging under mild reducing conditions. We demonstrate the potential of Frémy's salt, (i) showing that both 1H and 13C polarization of ∼30% can be achieved and (ii) describing a hybrid sample shuttling system (HySSS) that can be used with any DDNP/NMR combination to remove the PA before NMR detection. This gadget mixes the hyperpolarized solution with a radical scavenger and injects it into an NMR tube, providing, within a few seconds, quantitatively radical-free, highly polarized solutions. The cost efficiency and broad availability of Frémy's salt might facilitate the use of DDNP in many fields of research.
Collapse
Affiliation(s)
- Mattia Negroni
- Faculty
of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Straße 38, 1090 Vienna, Austria
| | - Ertan Turhan
- Faculty
of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Straße 38, 1090 Vienna, Austria
| | - Thomas Kress
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K.
| | - Morgan Ceillier
- Centre
de Résonance Magnétique Nucléaire à Très
Hauts Champs (UMR 5082) Université de Lyon/CNRS/Université
Claude Bernard Lyon 1/ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Sami Jannin
- Centre
de Résonance Magnétique Nucléaire à Très
Hauts Champs (UMR 5082) Université de Lyon/CNRS/Université
Claude Bernard Lyon 1/ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Dennis Kurzbach
- Faculty
of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Straße 38, 1090 Vienna, Austria
| |
Collapse
|
7
|
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).
Collapse
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
| |
Collapse
|
8
|
Pham P, Mandal R, Qi C, Hilty C. Interfacing Liquid State Hyperpolarization Methods with NMR Instrumentation. JOURNAL OF MAGNETIC RESONANCE OPEN 2022; 10-11:100052. [PMID: 35530721 PMCID: PMC9070690 DOI: 10.1016/j.jmro.2022.100052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Advances in liquid state hyperpolarization methods have enabled new applications of high-resolution NMR spectroscopy. Utilizing strong signal enhancements from hyperpolarization allows performing NMR spectroscopy at low concentration, or with high time resolution. Making use of the high, but rapidly decaying hyperpolarization in the liquid state requires new techniques to interface hyperpolarization equipment with liquid state NMR spectrometers. This article highlights rapid injection, high resolution NMR spectroscopy with hyperpolarization produced by the techniques of dissolution dynamic nuclear polarization (D-DNP) and para-hydrogen induced polarization (PHIP). These are popular, albeit not the only methods to produce high polarization levels for liquid samples. Gas and liquid driven sample injection techniques are compatible with both of these hyperpolarization methods. The rapid sample injection techniques are combined with adapted NMR experiments working in a single, or small number of scans. They expand the application of liquid state hyperpolarization to spins with comparably short relaxation times, provide enhanced control over sample conditions, and allow for mixing experiments to study reactions in real time.
Collapse
|
9
|
|
10
|
Elliott SJ, Stern Q, Ceillier M, El Daraï T, Cousin SF, Cala O, Jannin S. Practical dissolution dynamic nuclear polarization. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 126-127:59-100. [PMID: 34852925 DOI: 10.1016/j.pnmrs.2021.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 06/13/2023]
Abstract
This review article intends to provide insightful advice for dissolution-dynamic nuclear polarization in the form of a practical handbook. The goal is to aid research groups to effectively perform such experiments in their own laboratories. Previous review articles on this subject have covered a large number of useful topics including instrumentation, experimentation, theory, etc. The topics to be addressed here will include tips for sample preparation and for checking sample health; a checklist to correctly diagnose system faults and perform general maintenance; the necessary mechanical requirements regarding sample dissolution; and aids for accurate, fast and reliable polarization quantification. Herein, the challenges and limitations of each stage of a typical dissolution-dynamic nuclear polarization experiment are presented, with the focus being on how to quickly and simply overcome some of the limitations often encountered in the laboratory.
Collapse
Affiliation(s)
- Stuart J Elliott
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Quentin Stern
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Morgan Ceillier
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Théo El Daraï
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Samuel F Cousin
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Olivier Cala
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Sami Jannin
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs - UMR 5082 Université de Lyon, CNRS, Université Claude Bernard Lyon 1, ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France.
| |
Collapse
|
11
|
Hyperpolarization via dissolution dynamic nuclear polarization: new technological and methodological advances. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2020; 34:5-23. [PMID: 33185800 DOI: 10.1007/s10334-020-00894-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/04/2020] [Accepted: 10/23/2020] [Indexed: 12/20/2022]
Abstract
Dissolution-DNP is a method to boost liquid-state NMR sensitivity by several orders of magnitude. The technique consists in hyperpolarizing samples by solid-state dynamic nuclear polarization at low temperature and moderate magnetic field, followed by an instantaneous melting and dilution of the sample happening inside the polarizer. Although the technique is well established and the outstanding signal enhancement paved the way towards many applications precluded to conventional NMR, the race to develop new methods allowing higher throughput, faster and higher polarization, and longer exploitation of the signal is still vivid. In this work, we review the most recent advances on dissolution-DNP methods trying to overcome the original technique's shortcomings. The review describes some of the new approaches in the field, first, in terms of sample formulation and properties, and second, in terms of instrumentation.
Collapse
|
12
|
Cheng T, Gaunt AP, Marco-Rius I, Gehrung M, Chen AP, van der Klink JJ, Comment A. A multisample 7 T dynamic nuclear polarization polarizer for preclinical hyperpolarized MR. NMR IN BIOMEDICINE 2020; 33:e4264. [PMID: 31999867 PMCID: PMC7165016 DOI: 10.1002/nbm.4264] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/19/2019] [Accepted: 01/15/2020] [Indexed: 05/29/2023]
Abstract
Dynamic nuclear polarization (DNP) provides the opportunity to boost liquid state magnetic resonance (MR) signals from selected nuclear spins by several orders of magnitude. A cryostat running at a temperature of ~ 1 K and a superconducting magnet set to between 3 and 10 T are required to efficiently hyperpolarize nuclear spins. Several DNP polarizers have been implemented for the purpose of hyperpolarized MR and recent systems have been designed to avoid the need for user input of liquid cryogens. We herein present a zero boil-off DNP polarizer that operates at 1.35 ± 0.01 K and 7 T, and which can polarize two samples in parallel. The samples are cooled by a static helium bath thermally connected to a 1 K closed-cycle 4 He refrigerator. Using a modified version of the commercial fluid path developed for the SPINlab polarizer, we demonstrate that, within a 12-minute interval, the system can produce two separate hyperpolarized 13 C solutions. The 13 C liquid-state polarization of [1-13 C]pyruvate measured 26 seconds after dissolution was 36%, which can be extrapolated to a 55% solid state polarization. The system is well adapted for in vitro and in vivo preclinical hyperpolarized MR experiments and it can be modified to polarize up to four samples in parallel.
Collapse
Affiliation(s)
- Tian Cheng
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Adam P Gaunt
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Irene Marco-Rius
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Marcel Gehrung
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Albert P Chen
- General Electric Healthcare, Toronto, Ontario, Canada
| | | | - Arnaud Comment
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- General Electric Healthcare, Chalfont St Giles, UK
| |
Collapse
|
13
|
Harris T, Gamliel A, Nardi-Schreiber A, Sosna J, Gomori JM, Katz-Brull R. The Effect of Gadolinium Doping in [ 13 C 6 , 2 H 7 ]Glucose Formulations on 13 C Dynamic Nuclear Polarization at 3.35 T. Chemphyschem 2020; 21:251-256. [PMID: 31922367 DOI: 10.1002/cphc.201900946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 12/10/2019] [Indexed: 12/27/2022]
Abstract
The promise of hyperpolarized glucose as a non-radioactive imaging agent capable of reporting on multiple metabolic routes has led to recent advances in its dissolution-DNP (dDNP) driven polarization using UV-light induced radicals and trityl radicals at high field (6.7 T) and 1.1 K. However, most preclinical dDNP polarizers operate at the field of 3.35 T and 1.4-1.5 K. Minute amounts of Gd3+ complexes have shown large improvements in solid-state polarization, which can be translated to improved hyperpolarization in solution. However, this Gd3+ effect seems to depend on magnetic field strength, metal ion concentration, and sample formulation. The effect of varying Gd3+ concentrations at 3.35 T has been described for 13 C-labeled pyruvic acid and acetate. However, it has not been studied for other compounds at this field. The results presented here suggest that Gd3+ doping can lead to various concentration and temperature dependent effects on the polarization of [13 C6 ,2 H7 ]glucose, not necessarily similar to the effects observed in pyruvic acid or acetate in size or direction. The maximal polarization for [13 C6 ,2 H7 ]glucose appears to be at a Gd3+ concentration of 2 mM, when irradiating for more than 2 h at the negative maximum of the DNP intensity profile. Surprisingly, for shorter irradiation times, higher polarization levels were determined at 1.50 K compared to 1.45 K, at a [Gd3+ ]=1.3 mM. This was explained by the build-up time constant and maximum at these temperatures.
Collapse
Affiliation(s)
- Talia Harris
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Ayelet Gamliel
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Atara Nardi-Schreiber
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - J Moshe Gomori
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Rachel Katz-Brull
- Department of Radiology, Hadassah Medical Center, Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| |
Collapse
|
14
|
Albannay MM, Vinther JMO, Capozzi A, Zhurbenko V, Ardenkjaer-Larsen JH. Optimized microwave delivery in dDNP. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 305:58-65. [PMID: 31220776 DOI: 10.1016/j.jmr.2019.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/09/2019] [Accepted: 06/10/2019] [Indexed: 06/09/2023]
Abstract
Dissolution dynamic nuclear polarization (dDNP) has permitted the production of highly polarized liquid-state samples, enabling real-time imaging of metabolic processes non-invasively in vivo. The desire for higher magnetic resonance sensitivity has led to the development of multiple home-built and commercial dDNP polarizers employing solid-state microwave sources. Providing efficient microwave delivery that avoids unwanted heating of the sample is a crucial step to achieve high nuclear polarization. Consequently, a process is described to reduce waveguide attenuation due to resistive loss thereby doubling the delivered power. A mirror and reflector are designed and tested to increase the microwave field density across the sample volume resulting in a 2.3 dB increase of delivered power. Thermal considerations with regards to waveguide geometry and dDNP probe design are discussed. A thermal model of the dDNP probe is computed and experimentally verified.
Collapse
Affiliation(s)
- Mohammed M Albannay
- Center for Hyperpolarization in Magnetic Resonance, Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
| | - Joachim M O Vinther
- Center for Hyperpolarization in Magnetic Resonance, Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
| | - Andrea Capozzi
- Center for Hyperpolarization in Magnetic Resonance, Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
| | - Vitaliy Zhurbenko
- Center for Hyperpolarization in Magnetic Resonance, Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark
| | - Jan Henrik Ardenkjaer-Larsen
- Center for Hyperpolarization in Magnetic Resonance, Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Denmark; GE Healthcare, Brøndby, Denmark.
| |
Collapse
|
15
|
Capozzi A, Patel S, Wenckebach WT, Karlsson M, Lerche MH, Ardenkjær-Larsen JH. Gadolinium Effect at High-Magnetic-Field DNP: 70% 13C Polarization of [U- 13C] Glucose Using Trityl. J Phys Chem Lett 2019; 10:3420-3425. [PMID: 31181932 DOI: 10.1021/acs.jpclett.9b01306] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We show that the trityl electron spin resonance (ESR) features, crucial for an efficient dynamic nuclear polarization (DNP) process, are sample-composition-dependent. Working at 6.7 T and 1.1 K with a generally applicable DNP sample solvent mixture such as water/glycerol plus trityl, the addition of Gd3+ leads to a dramatic increase in [U-13C] glucose polarization from 37 ± 4% to 69 ± 3%. This is the highest value reported to date and is comparable to what can be achieved on pyruvic acid. Moreover, performing ESR measurements under actual DNP conditions, we provide experimental evidence that gadolinium doping not only shortens the trityl electron spin-lattice relaxation time but also modifies the radical g-tensor. The latter yielded a considerable narrowing of the ESR spectrum line width. Finally, in the frame of the spin temperature theory, we discuss how these two phenomena affect the DNP performance.
Collapse
Affiliation(s)
- Andrea Capozzi
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology , Technical University of Denmark , Building 349 , 2800 Kongens Lyngby , Denmark
| | - Saket Patel
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology , Technical University of Denmark , Building 349 , 2800 Kongens Lyngby , Denmark
| | - W Thomas Wenckebach
- Paul Scherrer Institute , CH-5232 Villigen , Switzerland
- National High Magnetic Field Laboratory, UF, AMRIS , Gainesville , Florida 32611 , United States
| | - Magnus Karlsson
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology , Technical University of Denmark , Building 349 , 2800 Kongens Lyngby , Denmark
| | - Mathilde H Lerche
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology , Technical University of Denmark , Building 349 , 2800 Kongens Lyngby , Denmark
| | - Jan Henrik Ardenkjær-Larsen
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology , Technical University of Denmark , Building 349 , 2800 Kongens Lyngby , Denmark
- GE Healthcare , Park Alle 295 , 2605 Brøndby , Denmark
| |
Collapse
|
16
|
Jähnig F, Himmler A, Kwiatkowski G, Däpp A, Hunkeler A, Kozerke S, Ernst M. A spin-thermodynamic approach to characterize spin dynamics in TEMPO-based samples for dissolution DNP at 7 T field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 303:91-104. [PMID: 31030064 DOI: 10.1016/j.jmr.2019.04.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/12/2019] [Accepted: 04/19/2019] [Indexed: 06/09/2023]
Abstract
The spin dynamics of dissolution DNP samples consisting of 4.5 M [13C]urea in a mixture of (1/1)Vol glycerol/water using 4-Oxo-TEMPO as a radical was investigated. We analyzed the DNP dynamics as function of radical concentration at 7 T and 3.4 T static magnetic field as well as function of deuteration of the solvent matrix at the high field. The spin dynamics could be reproduced in all cases, at least qualitatively, by a thermodynamic model based on spin temperatures of the nuclear Zeeman baths and an electron non-Zeeman (dipolar) bath. We find, however, that at high field (7 T) and low radical concentrations (25 mM) the nuclear spins do not reach the same spin temperature indicating a weak coupling of the two baths. At higher radical concentrations, as well as for all radical concentrations at low field (3.4 T), the two nuclear Zeeman baths reach the same spin temperature within experimental errors. Additionally, the spin system was prepared with different initial conditions. For these cases, the thermodynamic model was able to predict the time evolution of the system well. While the DNP profiles do not give clear indications to a specific polarization transfer mechanism, at high field (7 T) increased coupling is seen. The EPR line shapes cannot clarify this in absence of ELDOR type experiments, nevertheless DNP profiles and dynamics under frequency-modulated microwave irradiation illustrate the expected increase in coupling between electrons with increasing radical concentration.
Collapse
Affiliation(s)
- Fabian Jähnig
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Aaron Himmler
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Grzegorz Kwiatkowski
- Institute for Biomedical Engineering, University and ETH Zürich, Gloriastrasse 35, 8092 Zürich, Switzerland
| | - Alexander Däpp
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Andreas Hunkeler
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zürich, Gloriastrasse 35, 8092 Zürich, Switzerland
| | - Matthias Ernst
- Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland.
| |
Collapse
|
17
|
Steinhauser J, Wespi P, Kwiatkowski G, Kozerke S. Production of highly polarized [1- 13 C]acetate by rapid decarboxylation of [2- 13 C]pyruvate - application to hyperpolarized cardiac spectroscopy and imaging. Magn Reson Med 2019; 82:1140-1149. [PMID: 31045272 DOI: 10.1002/mrm.27782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/27/2019] [Accepted: 04/03/2019] [Indexed: 11/10/2022]
Abstract
PURPOSE The objective of the present work was to develop and implement an efficient approach to hyperpolarize [1-13 C]acetate and apply it to in vivo cardiac spectroscopy and imaging. METHODS Rapid hydrogen peroxide induced decarboxylation was used to convert hyperpolarized [2-13 C]pyruvate into highly polarized [1-13 C]acetate employing an additional step following rapid dissolution of [2-13 C]pyruvate in a home-built multi-sample dissolution dynamic nuclear polarization system. Phantom dissolution experiments were conducted to determine optimal parameters of the decarboxylation reaction, retaining polarization and T1 of [1-13 C]acetate. In vivo feasibility of detecting [1-13 C]acetate metabolism is demonstrated using slice-selective spectroscopy and multi-echo imaging of [1-13 C]acetate and [1-13 C]acetylcarnitine in the healthy rat heart. RESULTS The first in vivo signal was observed ~23 s after dissolution. At the corresponding time point in the phantom experiments, 97.9 ± 0.4% of [2-13 C]pyruvate were converted into [1-13 C]acetate by the decarboxylation reaction. T1 and polarization of [1-13 C]acetate was determined to be 29.7 ± 1.9% and a 47.7 ± 0.5 s. Polarization levels of [2-13 C]pyruvate and [1-13 C]acetate were not significantly different after transfer to the scanner. In vivo, [1-13 C]acetate and [1-13 C]acetylcarnitine could be detected using spectroscopy and imaging. CONCLUSION Decarboxylation of hyperpolarized [2-13 C]pyruvate enables the efficient production of highly polarized [1-13 C]acetate that is applicable to study short-chain fatty acid metabolism in the in vivo heart.
Collapse
Affiliation(s)
- Jonas Steinhauser
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Patrick Wespi
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Grzegorz Kwiatkowski
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| |
Collapse
|
18
|
Fleck N, Hett T, Brode J, Meyer A, Richert S, Schiemann O. C–C Cross-Coupling Reactions of Trityl Radicals: Spin Density Delocalization, Exchange Coupling, and a Spin Label. J Org Chem 2019; 84:3293-3303. [DOI: 10.1021/acs.joc.8b03229] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Nico Fleck
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Tobias Hett
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Jonas Brode
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Andreas Meyer
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| | - Sabine Richert
- Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University Bonn, Wegelerstr. 12, 53115 Bonn, Germany
| |
Collapse
|
19
|
Fleck N, Schnakenburg G, Filippou AC, Schiemann O. Tris[2,2,6,6-tetra-methyl-8-(tri-methyl-sil-yl)benzo[1,2- d;4,5- d']bis-(1,3-di-thiol)-4-yl]methanol diethyl ether monosolvate. Acta Crystallogr E Crystallogr Commun 2018; 74:539-542. [PMID: 29765762 PMCID: PMC5946984 DOI: 10.1107/s2056989018004516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/17/2018] [Indexed: 11/20/2022]
Abstract
The title compound, a tri-aryl-methanol, C46H64OS12Si31, was synthesized via li-thia-tion of tris-2,2,6,6-tetra-methyl-benzo[1,2-d;4,5-d']bis-[1,3]di-thiol-4-yl-methanol, 2, and electrophilic quenching with tri-methyl-silyl chloride. The current crystal structure reveals information about the reactivity of this compound and compares well with the structure reported for the unsubstituted parent compound 2 [Driesschaert et al. (2012 ▸). Eur. J. Org. Chem.33, 6517-6525]. The title compound 1 forms mol-ecular propellers and crystallizes in P [Formula: see text], featuring an unusually long Si-Car bond of 1.910 (3) Å. Moreover, the geometry at the central quaternary carbon is rather trigonal-pyramidal than tetra-hedral due to vast intra-molecular stress. One tri-methyl-silyl group is disordered over two positions in a 0.504 (4):0.496 (4) ratio and one S atom is disordered over two positions in a 0.509 (7):0.491 (7) ratio. The contribution of disordered diethyl ether solvent mol-ecule(s) was removed using the PLATON SQUEEZE (Spek, 2015 ▸) solvent masking procedure. These solvent mol-ecules are not considered in the given chemical formula and other crystal data.
Collapse
Affiliation(s)
- Nico Fleck
- University of Bonn, Institute of Physical and Theoretical Chemistry, Wegelerstrasse 12, 53115 Bonn, Germany
| | - Gregor Schnakenburg
- University of Bonn, Institute of Inorganic Chemistry, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
| | - Alexander C. Filippou
- University of Bonn, Institute of Inorganic Chemistry, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
| | - Olav Schiemann
- University of Bonn, Institute of Physical and Theoretical Chemistry, Wegelerstrasse 12, 53115 Bonn, Germany
| |
Collapse
|
20
|
Sirusi AA, Suh EH, Kovacs Z, Merritt ME. The effect of Ho 3+ doping on 13C dynamic nuclear polarization at 5 T. Phys Chem Chem Phys 2018; 20:728-731. [PMID: 29242884 PMCID: PMC5761062 DOI: 10.1039/c7cp07198a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dissolution dynamic nuclear polarization was introduced in 2003 as a method for producing hyperpolarized 13C solutions suitable for metabolic imaging. The signal to noise ratio for the imaging experiment depends on the maximum polarization achieved in the solid state. Hence, optimization of the DNP conditions is essential. To acquire maximum polarization many parameters related to sample preparation can be modulated. Recently, it was demonstrated that Ho3+, Dy3+, Tb3+, and Gd3+ complexes enhance the polarization at 1.2 K and 3.35 T when using the trityl radical as the primary paramagnetic center. Here, we have investigated the influence of Ho-DOTA on 13C solid state DNP at 1.2 K and 5 T. We have performed 13C DNP on [1-13C] sodium acetate in 1 : 1 (v/v) water/glycerol with 15 mM trityl OX063 radicals in the presence of a series of Ho-DOTA concentrations (0, 0.5, 1, 2, 3, 5 mM). We have found that adding a small amount of Ho-DOTA in the sample preparation not only enhances the 13C polarization but also decreases the buildup time. The optimum Ho-DOTA concentration was 2 mM. In addition, the microwave sweep spectrum changes character in a manner that suggests both the cross effect and thermal mixing are active mechanisms for trityl radical at 5 T and 1.2 K.
Collapse
Affiliation(s)
- Ali A. Sirusi
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, USA
| | - Eul Hyun Suh
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Zoltan Kovacs
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Matthew E. Merritt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, USA
| |
Collapse
|
21
|
Kwiatkowski G, Jähnig F, Steinhauser J, Wespi P, Ernst M, Kozerke S. Direct hyperpolarization of micro- and nanodiamonds for bioimaging applications - Considerations on particle size, functionalization and polarization loss. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 286:42-51. [PMID: 29183003 DOI: 10.1016/j.jmr.2017.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/13/2017] [Accepted: 11/17/2017] [Indexed: 06/07/2023]
Abstract
Due to the inherently long relaxation time of 13C spins in diamond, the nuclear polarization enhancement obtained with dynamic nuclear polarization can be preserved for a time on the order of about one hour, opening up an opportunity to use diamonds as a new class of long-lived contrast agents. The present communication explores the feasibility of using 13C spins in directly hyperpolarized diamonds for MR imaging including considerations for potential in vivo applications.
Collapse
Affiliation(s)
| | - Fabian Jähnig
- Laboratory of Physical Chemistry, ETH Zurich, Switzerland
| | - Jonas Steinhauser
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Patrick Wespi
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Matthias Ernst
- Laboratory of Physical Chemistry, ETH Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
| |
Collapse
|