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Wolff N, Beuck C, Schaller T, Epple M. Possibilities and limitations of solution-state NMR spectroscopy to analyze the ligand shell of ultrasmall metal nanoparticles. NANOSCALE ADVANCES 2024; 6:3285-3298. [PMID: 38933863 PMCID: PMC11197423 DOI: 10.1039/d4na00139g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024]
Abstract
Ultrasmall nanoparticles have a diameter between 1 and 3 nm at the border between nanoparticles and large molecules. Usually, their core consists of a metal, and the shell of a capping ligand with sulfur or phosphorus as binding atoms. While the core structure can be probed by electron microscopy, electron and powder diffraction, and single-crystal structure analysis for atom-sharp clusters, it is more difficult to analyze the ligand shell. In contrast to larger nanoparticles, ultrasmall nanoparticles cause only a moderate distortion of the NMR signal, making NMR spectroscopy a qualitative as well as a quantitative probe to assess the nature of the ligand shell. The application of isotope-labelled ligands and of two-dimensional NMR techniques can give deeper insight into ligand-nanoparticle interactions. Applications of one- and two-dimensional NMR spectroscopy to analyze ultrasmall nanoparticles are presented with suitable examples, including a critical discussion of the limitations of NMR spectroscopy on nanoparticles.
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Affiliation(s)
- Natalie Wolff
- Inorganic Chemistry, Centre for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen 45117 Essen Germany
| | - Christine Beuck
- Structural and Medicinal Biochemistry, Centre for Medical Biotechnology (ZMB), University of Duisburg-Essen 45117 Essen Germany
| | - Torsten Schaller
- Organic Chemistry, University of Duisburg-Essen 45117 Essen Germany
| | - Matthias Epple
- Inorganic Chemistry, Centre for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen 45117 Essen Germany
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2
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Rao Y, De Biasi F, Wei R, Copéret C, Emsley L. Probing Homogeneous Catalysts and Precatalysts in Solution by Exchange-Mediated Overhauser Dynamic Nuclear Polarization NMR. J Am Chem Soc 2024; 146:12587-12594. [PMID: 38685488 PMCID: PMC11082894 DOI: 10.1021/jacs.4c01570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 05/02/2024]
Abstract
Triphenylphosphine (PPh3) is a ubiquitous ligand in organometallic chemistry that has been shown to give enhanced 31P NMR signals at high magnetic field via a scalar-dominated Overhauser effect dynamic nuclear polarization (OE DNP). However, PPh3 can only be polarized via DNP in the free form, while the coordinated form is DNP-inactive. Here, we demonstrate the possibility of enhancing the 31P NMR signals of coordinated PPh3 in metal complexes in solution at room temperature by combining Overhauser effect DNP and chemical exchange between the free and coordinated PPh3 forms. With this method, we successfully obtain 31P DNP enhancements of up to 2 orders of magnitude for the PPh3 ligands in Rh(I), Ru(II), Pd(II), and Pt(II) complexes, and we show that the DNP enhancements can be used to determine the activation energy of the ligand exchange reaction.
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Affiliation(s)
- Yu Rao
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Federico De Biasi
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ran Wei
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Christophe Copéret
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, CH-8093 Zürich, Switzerland
| | - Lyndon Emsley
- Institut
des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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3
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Eills J, Hale W, Utz M. Synergies between Hyperpolarized NMR and Microfluidics: A Review. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 128:44-69. [PMID: 35282869 DOI: 10.1016/j.pnmrs.2021.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 06/14/2023]
Abstract
Hyperpolarized nuclear magnetic resonance and lab-on-a-chip microfluidics are two dynamic, but until recently quite distinct, fields of research. Recent developments in both areas increased their synergistic overlap. By microfluidic integration, many complex experimental steps can be brought together onto a single platform. Microfluidic devices are therefore increasingly finding applications in medical diagnostics, forensic analysis, and biomedical research. In particular, they provide novel and powerful ways to culture cells, cell aggregates, and even functional models of entire organs. Nuclear magnetic resonance is a non-invasive, high-resolution spectroscopic technique which allows real-time process monitoring with chemical specificity. It is ideally suited for observing metabolic and other biological and chemical processes in microfluidic systems. However, its intrinsically low sensitivity has limited its application. Recent advances in nuclear hyperpolarization techniques may change this: under special circumstances, it is possible to enhance NMR signals by up to 5 orders of magnitude, which dramatically extends the utility of NMR in the context of microfluidic systems. Hyperpolarization requires complex chemical and/or physical manipulations, which in turn may benefit from microfluidic implementation. In fact, many hyperpolarization methodologies rely on processes that are more efficient at the micro-scale, such as molecular diffusion, penetration of electromagnetic radiation into a sample, or restricted molecular mobility on a surface. In this review we examine the confluence between the fields of hyperpolarization-enhanced NMR and microfluidics, and assess how these areas of research have mutually benefited one another, and will continue to do so.
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Affiliation(s)
- James Eills
- Institute for Physics, Johannes Gutenberg University, D-55090 Mainz, Germany; GSI Helmholtzzentrum für Schwerionenforschung GmbH, Helmholtz-Institut Mainz, 55128 Mainz, Germany.
| | - William Hale
- Department of Chemistry, University of Florida, 32611, USA
| | - Marcel Utz
- School of Chemistry, University of Southampton, SO17 1BJ, UK.
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4
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Khan AS, Harvey RL, Birchall JR, Irwin RK, Nikolaou P, Schrank G, Emami K, Dummer A, Barlow MJ, Goodson BM, Chekmenev EY. Enabling Clinical Technologies for Hyperpolarized 129 Xenon Magnetic Resonance Imaging and Spectroscopy. Angew Chem Int Ed Engl 2021; 60:22126-22147. [PMID: 34018297 PMCID: PMC8478785 DOI: 10.1002/anie.202015200] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Indexed: 11/06/2022]
Abstract
Hyperpolarization is a technique that can increase nuclear spin polarization with the corresponding gains in nuclear magnetic resonance (NMR) signals by 4-8 orders of magnitude. When this process is applied to biologically relevant samples, the hyperpolarized molecules can be used as exogenous magnetic resonance imaging (MRI) contrast agents. A technique called spin-exchange optical pumping (SEOP) can be applied to hyperpolarize noble gases such as 129 Xe. Techniques based on hyperpolarized 129 Xe are poised to revolutionize clinical lung imaging, offering a non-ionizing, high-contrast alternative to computed tomography (CT) imaging and conventional proton MRI. Moreover, CT and conventional proton MRI report on lung tissue structure but provide little functional information. On the other hand, when a subject breathes hyperpolarized 129 Xe gas, functional lung images reporting on lung ventilation, perfusion and diffusion with 3D readout can be obtained in seconds. In this Review, the physics of SEOP is discussed and the different production modalities are explained in the context of their clinical application. We also briefly compare SEOP to other hyperpolarization methods and conclude this paper with the outlook for biomedical applications of hyperpolarized 129 Xe to lung imaging and beyond.
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Affiliation(s)
- Alixander S Khan
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Rebecca L Harvey
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Jonathan R Birchall
- Intergrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), 5101 Cass Avenue, Detroit, MI, 48202, USA
| | - Robert K Irwin
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | - Geoffry Schrank
- Northrup Grumman Space Systems, 45101 Warp Drive, Sterling, VA, 20166, USA
| | | | | | - Michael J Barlow
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Boyd M Goodson
- Department of Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL, 62901, USA
- Materials Technology Center, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL, 62901, USA
| | - Eduard Y Chekmenev
- Intergrative Biosciences (Ibio), Wayne State University, Karmanos Cancer Institute (KCI), 5101 Cass Avenue, Detroit, MI, 48202, USA
- Russian Academy of Sciences, Leninskiy Prospekt 14, Moscow, 119991, Russia
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Fiedorowicz M, Wieteska M, Rylewicz K, Kossowski B, Piątkowska-Janko E, Czarnecka AM, Toczylowska B, Bogorodzki P. Hyperpolarized 13C tracers: Technical advancements and perspectives for clinical applications. Biocybern Biomed Eng 2021. [DOI: 10.1016/j.bbe.2021.03.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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6
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Khan AS, Harvey RL, Birchall JR, Irwin RK, Nikolaou P, Schrank G, Emami K, Dummer A, Barlow MJ, Goodson BM, Chekmenev EY. Enabling Clinical Technologies for Hyperpolarized
129
Xenon Magnetic Resonance Imaging and Spectroscopy. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Alixander S. Khan
- Sir Peter Mansfield Imaging Centre University of Nottingham Nottingham NG7 2RD UK
| | - Rebecca L. Harvey
- Sir Peter Mansfield Imaging Centre University of Nottingham Nottingham NG7 2RD UK
| | - Jonathan R. Birchall
- Intergrative Biosciences (Ibio) Wayne State University, Karmanos Cancer Institute (KCI) 5101 Cass Avenue Detroit MI 48202 USA
| | - Robert K. Irwin
- Sir Peter Mansfield Imaging Centre University of Nottingham Nottingham NG7 2RD UK
| | | | - Geoffry Schrank
- Northrup Grumman Space Systems 45101 Warp Drive Sterling VA 20166 USA
| | | | | | - Michael J. Barlow
- Sir Peter Mansfield Imaging Centre University of Nottingham Nottingham NG7 2RD UK
| | - Boyd M. Goodson
- Department of Chemistry and Biochemistry Southern Illinois University 1245 Lincoln Drive Carbondale IL 62901 USA
- Materials Technology Center Southern Illinois University 1245 Lincoln Drive Carbondale IL 62901 USA
| | - Eduard Y. Chekmenev
- Intergrative Biosciences (Ibio) Wayne State University, Karmanos Cancer Institute (KCI) 5101 Cass Avenue Detroit MI 48202 USA
- Russian Academy of Sciences Leninskiy Prospekt 14 Moscow 119991 Russia
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7
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Gizatullin B, Mattea C, Stapf S. Molecular Dynamics in Ionic Liquid/Radical Systems. J Phys Chem B 2021; 125:4850-4862. [PMID: 33930266 DOI: 10.1021/acs.jpcb.1c02118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular dynamics of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (Emim-Tf2N) with either of the four organic stable radicals, TEMPO, 4-benzoyloxy-TEMPO, BDPA, and DPPH, is studied by using Nuclear Magnetic Resonance (NMR) and Dynamic Nuclear Polarization (DNP). In complex fluids at ambient temperature, NMR signal enhancement by DNP is frequently obtained by a combination of several mechanisms, where the Overhauser effect and solid effect are the most common. Understanding the interactions of free radicals with ionic liquid molecules is of particular significance due to their complex dynamics in these systems, influencing the properties of the ion-radical interaction. A combined analysis of EPR, DNP, and NMR relaxation dispersion is carried out for cations and anions containing, respectively, the NMR active nuclei 1H or 19F. Depending on the size and the chemical properties of the radical, different interaction processes are distinguished, namely, the Overhauser effect and solid effect, driven by dominating dipolar or scalar interactions. The resulting NMR relaxation dispersion is decomposed into rotational and translational contributions, allowing the identification of the corresponding correlation times of motion and interactions. The influence of electron relaxation time and electron-nuclear spin hyperfine coupling is discussed.
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Affiliation(s)
- Bulat Gizatullin
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
| | - Carlos Mattea
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
| | - Siegfried Stapf
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
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8
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Gizatullin B, Mattea C, Stapf S. Field-cycling NMR and DNP - A friendship with benefits. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 322:106851. [PMID: 33423755 DOI: 10.1016/j.jmr.2020.106851] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 06/12/2023]
Abstract
Field-cycling relaxometry, or rather its electronic version with a resistive magnet which requires signal detection at a field strength of 1 Tesla or below, remains an inherently insensitive technique due to the construction compromise that goes along with the need for a fast-switching, low-inductance magnet. For the same reasons, signal lifetime is short and frequency resolution is typically not given, at least for the predominantly used hydrogen nuclei. Dynamic Nuclear Polarization (DNP) bears the potential to circumvent these disadvantages: not only has it been demonstrated to enhance magnetization by up to three orders of magnitude beyond its thermal value, but it also provides the possibility to address particular parts of a molecule, thus generating selectivity even in the absence of spectral resolution. At the same time, DNP requires the introduction of stable radicals giving rise to additional relaxation contributions. This article presents a straightforward way to recover the native relaxation rates of the undisturbed system, and shows examples in different research fields where field-cycling relaxometry is traditionally used for refining models of molecular dynamics and interactions.
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Affiliation(s)
- Bulat Gizatullin
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
| | - Carlos Mattea
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
| | - Siegfried Stapf
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany.
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9
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Hyperpolarized 15N-labeled, deuterated tris (2-pyridylmethyl)amine as an MRI sensor of freely available Zn 2. Commun Chem 2020; 3. [PMID: 34212118 PMCID: PMC8244538 DOI: 10.1038/s42004-020-00426-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Dynamic nuclear polarization (DNP) coupled with 15N magnetic resonance imaging (MRI) provides an opportunity to image quantitative levels of biologically important metal ions such as Zn2+, Mg2+ or Ca2+ using appropriately designed 15N enriched probes. For example, a Zn-specific probe could prove particularly valuable for imaging the tissue distribution of freely available Zn2+ ions, an important known metal ion biomarker in the pancreas, in prostate cancer, and in several neurodegenerative diseases. In the present study, we prepare the cell-permeable, 15N-enriched, d6-deuterated version of the well-known Zn2+ chelator, tris(2-pyridylmethyl)amine (TPA) and demonstrate that the polarized ligand had favorable T1 and linewidth characteristics for 15N MRI. Examples of how polarized TPA can be used to quantify freely available Zn2+ in homogenized human prostate tissue and intact cells are presented.
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10
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Singh J, Suh EH, Sharma G, Khemtong C, Sherry AD, Kovacs Z. Probing carbohydrate metabolism using hyperpolarized 13 C-labeled molecules. NMR IN BIOMEDICINE 2019; 32:e4018. [PMID: 30474153 PMCID: PMC6579721 DOI: 10.1002/nbm.4018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/03/2018] [Accepted: 08/11/2018] [Indexed: 05/05/2023]
Abstract
Glycolysis is a fundamental metabolic process in all organisms. Anomalies in glucose metabolism are linked to various pathological conditions. In particular, elevated aerobic glycolysis is a characteristic feature of rapidly growing cells. Glycolysis and the closely related pentose phosphate pathway can be monitored in real time by hyperpolarized 13 C-labeled metabolic substrates such as 13 C-enriched, deuterated D-glucose derivatives, [2-13 C]-D-fructose, [2-13 C] dihydroxyacetone, [1-13 C]-D-glycerate, [1-13 C]-D-glucono-δ-lactone and [1-13 C] pyruvate in healthy and diseased tissues. Elevated glycolysis in tumors (the Warburg effect) was also successfully imaged using hyperpolarized [U-13 C6 , U-2 H7 ]-D-glucose, while the size of the preexisting lactate pool can be measured by 13 C MRS and/or MRI with hyperpolarized [1-13 C]pyruvate. This review summarizes the application of various hyperpolarized 13 C-labeled metabolites to the real-time monitoring of glycolysis and related metabolic processes in normal and diseased tissues.
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Affiliation(s)
- Jaspal Singh
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eul Hyun Suh
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gaurav Sharma
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chalermchai Khemtong
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - A. Dean Sherry
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Zoltan Kovacs
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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11
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Ranjan R, Sinha N. Nuclear magnetic resonance (NMR)-based metabolomics for cancer research. NMR IN BIOMEDICINE 2019; 32:e3916. [PMID: 29733484 DOI: 10.1002/nbm.3916] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/01/2018] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Nuclear magnetic resonance (NMR) has emerged as an effective tool in various spheres of biomedical research, amongst which metabolomics is an important method for the study of various types of disease. Metabolomics has proved its stronghold in cancer research by the development of different NMR methods over time for the study of metabolites, thus identifying key players in the aetiology of cancer. A plethora of one-dimensional and two-dimensional NMR experiments (in solids, semi-solids and solution phases) are utilized to obtain metabolic profiles of biofluids, cell extracts and tissue biopsy samples, which can further be subjected to statistical analysis. Any alteration in the assigned metabolite peaks gives an indication of changes in metabolic pathways. These defined changes demonstrate the utility of NMR in the early diagnosis of cancer and provide further measures to combat malignancy and its progression. This review provides a snapshot of the trending NMR techniques and the statistical analysis involved in the metabolomics of diseases, with emphasis on advances in NMR methodology developed for cancer research.
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Affiliation(s)
- Renuka Ranjan
- Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow, India
- School of Biotechnology, Institute of Science Banaras Hindu University, Varanasi, India
| | - Neeraj Sinha
- Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow, India
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12
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In-Cell NMR: Analysis of Protein-Small Molecule Interactions, Metabolic Processes, and Protein Phosphorylation. Int J Mol Sci 2019; 20:ijms20020378. [PMID: 30658393 PMCID: PMC6359726 DOI: 10.3390/ijms20020378] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 01/31/2023] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy enables the non-invasive observation of biochemical processes, in living cells, at comparably high spectral and temporal resolution. Preferably, means of increasing the detection limit of this powerful analytical method need to be applied when observing cellular processes under physiological conditions, due to the low sensitivity inherent to the technique. In this review, a brief introduction to in-cell NMR, protein–small molecule interactions, posttranslational phosphorylation, and hyperpolarization NMR methods, used for the study of metabolites in cellulo, are presented. Recent examples of method development in all three fields are conceptually highlighted, and an outlook into future perspectives of this emerging area of NMR research is given.
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13
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Khattri RB, Sirusi AA, Suh EH, Kovacs Z, Merritt ME. The influence of Ho 3+ doping on 13C DNP in the presence of BDPA. Phys Chem Chem Phys 2019; 21:18629-18635. [PMID: 31414686 DOI: 10.1039/c9cp03717a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Polarization transfer from unpaired electron radicals to nuclear spins at low-temperature is achieved using microwave irradiation by a process broadly termed dynamic nuclear polarization (DNP). The resulting signal enhancement can easily exceed factors of 104 when paired with cryogenic cooling of the sample. Dissolution-DNP couples low temperature polarization methods with a rapid dissolution step, resulting in a highly polarized solution that can be used for metabolically sensitive magnetic resonance imaging (MRI). Hyperpolarized [1-13C]pyruvate is a powerful metabolic imaging agent for investigation of in vitro and in vivo cellular metabolism by means of NMR spectroscopy and MRI. Radicals (trityl OX063 and BDPA) with narrower EPR linewidths typically produce higher nuclear polarizations when carbon-13 is the target nucleus. Increased solid-state polarization is observed when narrow line radicals are doped with lanthanide ions such as Gd3+, Ho3+, Dy3+, and Tb3+. Earlier results have demonstrated an incongruence between DNP experiments with trityl and BDPA, where the optimal concentrations for polarization transfer are disparate despite similar electron spin resonance linewidths. Here, the effects of Ho-DOTA on the solid-state polarization of [1-13C]pyruvic acid were compared for 3.35 T (1.4 K) and 5 T (1.2 K) systems using BDPA as a radical. Multiple concentrations of BDPA were doped with variable concentrations of Ho-DOTA (0, 0.2, 0.5, 1, and 2 mM), and dissolved in 1 : 1 (v/v) of [1-13C] pyruvic acid/sulfolane mixture. Our results reveal that addition of small amounts of Ho-DOTA in the sample preparation increases the solid-state polarization for [1-13C] pyruvic acid, with the optimum Ho-DOTA concentration of 0.2 mM. Without Ho-DOTA doping, the optimum BDPA concentration found for 3.35 T (1.4 K) is 40 mM, and for 5 T (1.2 K) system it is about 60 mM. In both systems, inclusion of Ho-DOTA in the 13C DNP sample leads to a change in the breadth (ΔDNP) of the extrema between the P(+) and P(-) frequencies in microwave spectra. At no combination of BDPA and Ho3+ did polarizations reach those achievable with trityl. Simplified analysis of increased polarization as a function of decreased electron T1e used to explain results in trityl are insufficient to describe DNP with BDPA.
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Affiliation(s)
- Ram B Khattri
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, USA.
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14
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Niedbalski P, Kiswandhi A, Parish C, Wang Q, Khashami F, Lumata L. NMR Spectroscopy Unchained: Attaining the Highest Signal Enhancements in Dissolution Dynamic Nuclear Polarization. J Phys Chem Lett 2018; 9:5481-5489. [PMID: 30179503 DOI: 10.1021/acs.jpclett.8b01687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dynamic nuclear polarization (DNP) via the dissolution method is one of the most successful methods for alleviating the inherently low Boltzmann-dictated sensitivity in nuclear magnetic resonance (NMR) spectroscopy. This emerging technology has already begun to positively impact chemical and metabolic research by providing the much-needed enhancement of the liquid-state NMR signals of insensitive nuclei such as 13C by several thousand-fold. In this Perspective, we present our viewpoints regarding the key elements needed to maximize the NMR signal enhancements in dissolution DNP, from the very core of the DNP process at cryogenic temperatures, DNP instrumental conditions, and chemical tuning in sample preparation to current developments in minimizing hyperpolarization losses during the dissolution transfer process. The optimization steps discussed herein could potentially provide important experimental and theoretical considerations in harnessing the best possible sensitivity gains in NMR spectroscopy as afforded by optimized dissolution DNP technology.
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Affiliation(s)
- Peter Niedbalski
- Department of Physics , The University of Texas at Dallas , 800 West Campbell Road , Richardson , Texas 75080 , United States
| | - Andhika Kiswandhi
- Department of Physics , The University of Texas at Dallas , 800 West Campbell Road , Richardson , Texas 75080 , United States
| | - Christopher Parish
- Department of Physics , The University of Texas at Dallas , 800 West Campbell Road , Richardson , Texas 75080 , United States
| | - Qing Wang
- Department of Physics , The University of Texas at Dallas , 800 West Campbell Road , Richardson , Texas 75080 , United States
| | - Fatemeh Khashami
- Department of Physics , The University of Texas at Dallas , 800 West Campbell Road , Richardson , Texas 75080 , United States
| | - Lloyd Lumata
- Department of Physics , The University of Texas at Dallas , 800 West Campbell Road , Richardson , Texas 75080 , United States
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15
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Blaffert J, Haeri HH, Blech M, Hinderberger D, Garidel P. Spectroscopic methods for assessing the molecular origins of macroscopic solution properties of highly concentrated liquid protein solutions. Anal Biochem 2018; 561-562:70-88. [PMID: 30243977 DOI: 10.1016/j.ab.2018.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 09/08/2018] [Accepted: 09/17/2018] [Indexed: 01/14/2023]
Abstract
In cases of subcutaneous injection of therapeutic monoclonal antibodies, high protein concentrations (>50 mg/ml) are often required. During the development of these high concentration liquid formulations (HCLF), challenges such as aggregation, gelation, opalescence, phase separation, and high solution viscosities are more prone compared to low concentrated protein formulations. These properties can impair manufacturing processes, as well as protein stability and shelf life. To avoid such unfavourable solution properties, a detailed understanding about the nature of these properties and their driving forces are required. However, the fundamental mechanisms that lead to macroscopic solution properties, as above mentioned, are complex and not fully understood, yet. Established analytical methods for assessing the colloidal stability, i.e. the ability of a native protein to remain dispersed in solution, are restricted to dilute conditions and provide parameters such as the second osmotic virial coefficient, B22, and the diffusion interaction coefficient, kD. These parameters are routinely applied for qualitative estimations and identifications of proteins with challenging solution behaviours, such as high viscosities and aggregation, although the assays are prepared for low protein concentration conditions, typically between 0.1 and 20 mg/ml ("ideal" solution conditions). Quantitative analysis of samples of high protein concentration is difficult and it is hard to obtain information about the driving forces of such solution properties and corresponding protein-protein self-interactions. An advantage of using specific spectroscopic methods is the potential of directly analysing highly concentrated protein solutions at different solution conditions. This allows for collecting/gaining valuable information about the fundamental mechanisms of solution properties of the high protein concentration regime. In addition, the derived parameters might be more predictive as compared to the parameters originating from assays which are optimized for the low protein concentration range. The provided information includes structural data, molecular dynamics at various timescales and protein-solvent interactions, which can be obtained at molecular resolution. Herein, we provide an overview about spectroscopic techniques for analysing the origins of macroscopic solution behaviours in general, with a specific focus on pharmaceutically relevant high protein concentration and formulation conditions.
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Affiliation(s)
- Jacob Blaffert
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle/Saale, Germany
| | - Haleh Hashemi Haeri
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle/Saale, Germany
| | - Michaela Blech
- Boehringer Ingelheim Pharma GmbH & Co. KG, Protein Science, Birkerndorfer Str. 65, 88397, Biberach/Riß, Germany
| | - Dariush Hinderberger
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle/Saale, Germany
| | - Patrick Garidel
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle/Saale, Germany; Boehringer Ingelheim Pharma GmbH & Co. KG, Protein Science, Birkerndorfer Str. 65, 88397, Biberach/Riß, Germany.
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16
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Richards JE, Hooper AJJ, Bayfield OW, Cockett MCR, Dear GJ, Holmes AJ, John RO, Mewis RE, Pridmore N, Roberts AD, Whitwood AC, Duckett SB. Using hyperpolarised NMR and DFT to rationalise the unexpected hydrogenation of quinazoline to 3,4-dihydroquinazoline. Chem Commun (Camb) 2018; 54:10375-10378. [PMID: 30152480 PMCID: PMC6136267 DOI: 10.1039/c8cc04826f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 07/17/2018] [Indexed: 11/21/2022]
Abstract
PHIP and SABRE hyperpolarized NMR methods are used to follow the unexpected metal-catalysed hydrogenation of quinazoline (Qu) to 3,4-dihydroquinazoline as the sole product. A solution of [IrCl(IMes)(COD)] in dichloromethane reacts with H2 and Qu to form [IrCl(H)2(IMes)(Qu)2] (2). The addition of methanol then results in its conversion to [Ir(H)2(IMes)(Qu)3]Cl (3) which catalyses the hydrogenation reaction. Density functional theory calculations are used to rationalise a proposed outer sphere mechanism in which (3) converts to [IrCl(H)2(H2)(IMes)(Qu)2]Cl (4) and neutral [Ir(H)3(IMes)(Qu)2] (6), both of which are involved in the formation of 3,4-dihydroquinazoline via the stepwise transfer of H+ and H-, with H2 identified as the reductant. Successive ligand exchange in 3 results in the production of thermodynamically stable [Ir(H)2(IMes)(3,4-dihydroquinazoline)3]Cl (5).
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Affiliation(s)
- Josh E. Richards
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Alexander J. J. Hooper
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Oliver W. Bayfield
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Martin C. R. Cockett
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Gordon J. Dear
- GlaxoSmithKline Research and Development Ltd
, Park Road
,
Ware
, Hertfordshire
SG12 0DP
, UK
| | - A. Jonathon Holmes
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Richard O. John
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Ryan E. Mewis
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Natalie Pridmore
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Andy D. Roberts
- GlaxoSmithKline Research and Development Ltd
, Park Road
,
Ware
, Hertfordshire
SG12 0DP
, UK
| | - Adrian C. Whitwood
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
| | - Simon B. Duckett
- Centre for Hyperpolarisation in Magnetic Resonance
, University of York
,
Heslington
, York
YO10 5NY
, UK
.
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17
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Niedbalski P, Wang Q, Parish C, Khashami F, Kiswandhi A, Lumata L. Magnetic-Field-Dependent Lifetimes of Hyperpolarized 13C Spins at Cryogenic Temperature. J Phys Chem B 2018; 122:1898-1904. [PMID: 29369632 DOI: 10.1021/acs.jpcb.8b00630] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Using a home-built cryogen-free dynamic nuclear polarization (DNP) system with a variable magnetic field capability, 13C spin-lattice T1 relaxation times of hyperpolarized [1-13C] carboxylates (sodium acetate, glycine, sodium pyruvate, and pyruvic acid) doped with trityl OX063 free radical were systematically measured for the first time at different field strengths up to 9 T at T = 1.8 K. Our data reveal that the 13C T1 values of these frozen hyperpolarized 13C samples vary drastically with the applied magnetic field B according to an apparent empirical power-law dependence (13C T1 ∝ Bα, 2.3 < α < 3.1), with relaxation values ranging from a few hundred seconds at 1 T to over 200,000 s at fields close to 9 T. This low temperature relaxation behavior can be ascribed approximately to a model that accounts for the combined effect of 13C-1H intramolecular dipolar interaction and the relaxation contribution from the paramagnetic impurities present in the DNP sample. Since the lifetime or T1 storage of the hyperpolarized state is intimately linked to DNP efficiency, these 13C relaxation data at cryogenic temperature have important theoretical and experimental implications as the DNP of 13C-labeled biomolecules is pushed to higher magnetic fields.
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Affiliation(s)
- Peter Niedbalski
- Department of Physics, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Qing Wang
- Department of Physics, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Christopher Parish
- Department of Physics, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Fatemeh Khashami
- Department of Physics, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Andhika Kiswandhi
- Department of Physics, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Lloyd Lumata
- Department of Physics, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
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18
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Liu M, Hilty C. Metabolic Measurements of Nonpermeating Compounds in Live Cells Using Hyperpolarized NMR. Anal Chem 2018; 90:1217-1222. [PMID: 29227628 PMCID: PMC6200330 DOI: 10.1021/acs.analchem.7b03901] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hyperpolarization by dissolution dynamic nuclear polarization (D-DNP) has emerged as a technique for enhancing NMR signals by several orders of magnitude, thereby facilitating the characterization of metabolic pathways both in vivo and in vitro. Following the introduction of an externally hyperpolarized compound, real-time NMR enables the measurement of metabolic flux in the corresponding pathway. Spin relaxation however limits the maximum experimental time and prevents the use of this method with compounds exhibiting slow membrane transport rates. Here, we demonstrate that on-line electroporation can serve as a method for membrane permeabilization for use with D-DNP in cell cultures. An electroporation apparatus hyphenated with stopped-flow sample injection permits the introduction of the hyperpolarized metabolite within 3 s after the electrical pulse. In yeast cells that do not readily take up pyruvate, the addition of the electroporation pulse to the D-DNP experiment increases the signals of the downstream metabolic products CO2 and HCO3-, which otherwise are near the detection limit, by 8.2- and 8.6-fold. Modeling of the time dependence of these signals then permits the determination of the respective kinetic rate constants. The observed conversion rate from pyruvate to CO2 normalized for cell density was found to increase by a factor of 12 due to the alleviation of the membrane transport limitation. The use of electroporation therefore extends the applicability of D-DNP to in vitro studies with a wider range of metabolites and at the same time reduces the influence of membrane transport on the observed conversion rates.
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Affiliation(s)
- Mengxiao Liu
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA
| | - Christian Hilty
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA
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19
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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.
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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
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20
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Niedbalski P, Parish C, Wang Q, Kiswandhi A, Hayati Z, Song L, Lumata L. 13C Dynamic Nuclear Polarization Using a Trimeric Gd 3+ Complex as an Additive. J Phys Chem A 2017. [PMID: 28631929 DOI: 10.1021/acs.jpca.7b03869] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Dissolution dynamic nuclear polarization (DNP) is one of the most successful techniques that resolves the insensitivity problem in liquid-state nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) by amplifying the signal by several thousand-fold. One way to further improve the DNP signal is the inclusion of trace amounts of lanthanides in DNP samples doped with trityl OX063 free radical as the polarizing agent. In practice, stable monomeric gadolinium complexes such as Gd-DOTA or Gd-HP-DO3A are used as beneficial additives in DNP samples, further boosting the DNP-enhanced solid-state 13C polarization by a factor of 2 or 3. Herein, we report on the use of a trimeric gadolinium complex as a dopant in 13C DNP samples to improve the 13C DNP signals in the solid-state at 3.35 T and 1.2 K and consequently, in the liquid-state at 9.4 T and 298 K after dissolution. Our results have shown that doping the 13C DNP sample with a complex which holds three Gd3+ ions led to an improvement of DNP-enhanced 13C polarization by a factor of 3.4 in the solid-state, on par with those achieved using monomeric Gd3+ complexes but only requires about one-fifth of the concentration. Upon dissolution, liquid-state 13C NMR signal enhancements close to 20 000-fold, approximately 3-fold the enhancement of the control samples, were recorded in the nearby 9.4 T high resolution NMR magnet at room temperature. Comparable reduction of 13C spin-lattice T1 relaxation time was observed in the liquid-state after dissolution for both the monomeric and trimeric Gd3+ complexes. Moreover, W-band electron paramagnetic resonance (EPR) data have revealed that 3-Gd doping significantly reduces the electron T1 of the trityl OX063 free radical, but produces negligible changes in the EPR spectrum, reminiscent of the results with monomeric Gd3+-complex doping. Our data suggest that the trimeric Gd3+ complex is a highly beneficial additive in 13C DNP samples and that its effect on DNP efficiency can be described in the context of the thermal mixing mechanism.
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Affiliation(s)
- Peter Niedbalski
- Department of Physics, University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080 United States
| | - Christopher Parish
- Department of Physics, University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080 United States
| | - Qing Wang
- Department of Physics, University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080 United States
| | - Andhika Kiswandhi
- Department of Physics, University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080 United States
| | - Zahra Hayati
- National High Magnetic Field Laboratory, Florida State University , 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Likai Song
- National High Magnetic Field Laboratory, Florida State University , 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Lloyd Lumata
- Department of Physics, University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080 United States
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21
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Waddington DEJ, Sarracanie M, Zhang H, Salameh N, Glenn DR, Rej E, Gaebel T, Boele T, Walsworth RL, Reilly DJ, Rosen MS. Nanodiamond-enhanced MRI via in situ hyperpolarization. Nat Commun 2017; 8:15118. [PMID: 28443626 PMCID: PMC5414045 DOI: 10.1038/ncomms15118] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 03/01/2017] [Indexed: 11/05/2022] Open
Abstract
Nanodiamonds are of interest as nontoxic substrates for targeted drug delivery and as highly biostable fluorescent markers for cellular tracking. Beyond optical techniques, however, options for noninvasive imaging of nanodiamonds in vivo are severely limited. Here, we demonstrate that the Overhauser effect, a proton–electron polarization transfer technique, can enable high-contrast magnetic resonance imaging (MRI) of nanodiamonds in water at room temperature and ultra-low magnetic field. The technique transfers spin polarization from paramagnetic impurities at nanodiamond surfaces to 1H spins in the surrounding water solution, creating MRI contrast on-demand. We examine the conditions required for maximum enhancement as well as the ultimate sensitivity of the technique. The ability to perform continuous in situ hyperpolarization via the Overhauser mechanism, in combination with the excellent in vivo stability of nanodiamond, raises the possibility of performing noninvasive in vivo tracking of nanodiamond over indefinitely long periods of time. Hyperpolarized magnetic resonance imaging can enhance imaging contrast by orders of magnitude, but applications are limited by the thermal relaxation of hyperpolarized states. Here, Waddington et al. demonstrate the on-demand hyperpolarization of hydrogen spins through the Overhauser effect with nanodiamonds.
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Affiliation(s)
- David E J Waddington
- A.A. Martinos Center for Biomedical Imaging, Suite 2301, 149 13th Street, Charlestown, Massachusetts 02129, USA.,ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia.,Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Mathieu Sarracanie
- A.A. Martinos Center for Biomedical Imaging, Suite 2301, 149 13th Street, Charlestown, Massachusetts 02129, USA.,Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.,Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Huiliang Zhang
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.,Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA
| | - Najat Salameh
- A.A. Martinos Center for Biomedical Imaging, Suite 2301, 149 13th Street, Charlestown, Massachusetts 02129, USA.,Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.,Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115, USA
| | - David R Glenn
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.,Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA
| | - Ewa Rej
- ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Torsten Gaebel
- ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Thomas Boele
- ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Ronald L Walsworth
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.,Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA
| | - David J Reilly
- ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Matthew S Rosen
- A.A. Martinos Center for Biomedical Imaging, Suite 2301, 149 13th Street, Charlestown, Massachusetts 02129, USA.,Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.,Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115, USA
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22
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Segawa TF, Doppelbauer M, Garbuio L, Doll A, Polyhach YO, Jeschke G. Water accessibility in a membrane-inserting peptide comparing Overhauser DNP and pulse EPR methods. J Chem Phys 2017; 144:194201. [PMID: 27208942 DOI: 10.1063/1.4948988] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Water accessibility is a key parameter for the understanding of the structure of biomolecules, especially membrane proteins. Several experimental techniques based on the combination of electron paramagnetic resonance (EPR) spectroscopy with site-directed spin labeling are currently available. Among those, we compare relaxation time measurements and electron spin echo envelope modulation (ESEEM) experiments using pulse EPR with Overhauser dynamic nuclear polarization (DNP) at X-band frequency and a magnetic field of 0.33 T. Overhauser DNP transfers the electron spin polarization to nuclear spins via cross-relaxation. The change in the intensity of the (1)H NMR spectrum of H2O at a Larmor frequency of 14 MHz under a continuous-wave microwave irradiation of the nitroxide spin label contains information on the water accessibility of the labeled site. As a model system for a membrane protein, we use the hydrophobic α-helical peptide WALP23 in unilamellar liposomes of DOPC. Water accessibility measurements with all techniques are conducted for eight peptides with different spin label positions and low radical concentrations (10-20 μM). Consistently in all experiments, the water accessibility appears to be very low, even for labels positioned near the end of the helix. The best profile is obtained by Overhauser DNP, which is the only technique that succeeds in discriminating neighboring positions in WALP23. Since the concentration of the spin-labeled peptides varied, we normalized the DNP parameter ϵ, being the relative change of the NMR intensity, by the electron spin concentration, which was determined from a continuous-wave EPR spectrum.
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Affiliation(s)
- Takuya F Segawa
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Maximilian Doppelbauer
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Luca Garbuio
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Andrin Doll
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Yevhen O Polyhach
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
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23
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Niedbalski P, Parish C, Kiswandhi A, Fidelino L, Khemtong C, Hayati Z, Song L, Martins A, Sherry AD, Lumata L. Influence of Dy 3+ and Tb 3+ doping on 13C dynamic nuclear polarization. J Chem Phys 2017; 146:014303. [PMID: 28063445 PMCID: PMC5218971 DOI: 10.1063/1.4973317] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/14/2016] [Indexed: 12/28/2022] Open
Abstract
Dynamic nuclear polarization (DNP) is a technique that uses a microwave-driven transfer of high spin alignment from electrons to nuclear spins. This is most effective at low temperature and high magnetic field, and with the invention of the dissolution method, the amplified nuclear magnetic resonance (NMR) signals in the frozen state in DNP can be harnessed in the liquid-state at physiologically acceptable temperature for in vitro and in vivo metabolic studies. A current optimization practice in dissolution DNP is to dope the sample with trace amounts of lanthanides such as Gd3+ or Ho3+, which further improves the polarization. While Gd3+ and Ho3+ have been optimized for use in dissolution DNP, other lanthanides have not been exhaustively studied for use in C13 DNP applications. In this work, two additional lanthanides with relatively high magnetic moments, Dy3+ and Tb3+, were extensively optimized and tested as doping additives for C13 DNP at 3.35 T and 1.2 K. We have found that both of these lanthanides are also beneficial additives, to a varying degree, for C13 DNP. The optimal concentrations of Dy3+ (1.5 mM) and Tb3+ (0.25 mM) for C13 DNP were found to be less than that of Gd3+ (2 mM). W-band electron paramagnetic resonance shows that these enhancements due to Dy3+ and Tb3+ doping are accompanied by shortening of electron T1 of trityl OX063 free radical. Furthermore, when dissolution was employed, Tb3+-doped samples were found to have similar liquid-state C13 NMR signal enhancements compared to samples doped with Gd3+, and both Tb3+ and Dy3+ had a negligible liquid-state nuclear T1 shortening effect which contrasts with the significant reduction in T1 when using Gd3+. Our results show that Dy3+ doping and Tb3+ doping have a beneficial impact on C13 DNP both in the solid and liquid states, and that Tb3+ in particular could be used as a potential alternative to Gd3+ in C13 dissolution DNP experiments.
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Affiliation(s)
- Peter Niedbalski
- Department of Physics, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
| | - Christopher Parish
- Department of Physics, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
| | - Andhika Kiswandhi
- Department of Physics, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
| | - Leila Fidelino
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Chalermchai Khemtong
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Zahra Hayati
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Likai Song
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - André Martins
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - A Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA
| | - Lloyd Lumata
- Department of Physics, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
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24
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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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25
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Okuno Y, Cavagnero S. Fluorescein: A Photo-CIDNP Sensitizer Enabling Hypersensitive NMR Data Collection in Liquids at Low Micromolar Concentration. J Phys Chem B 2016; 120:715-23. [PMID: 26744790 PMCID: PMC4879942 DOI: 10.1021/acs.jpcb.5b12339] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photochemically induced dynamic nuclear polarization (photo-CIDNP) is a powerful approach for sensitivity enhancement in NMR spectroscopy. In liquids, intermolecular photo-CIDNP depends on the transient bimolecular reaction between photoexcited dye and sample of interest. Hence the extent of polarization is sample-concentration dependent. This study introduces fluorescein (FL) as a photo-CIDNP dye whose performance is exquisitely tailored to data collection at extremely low sample concentrations. The photo-CIDNP resonance intensities of tryptophan in the presence of either FL or FMN (i.e., the routinely employed flavin mononucleotide photosensitizer) in the liquid state show that FL yields superior sensitivity and enables rapid data collection down to an unprecedented 1 μM concentration. This result was achieved on a conventional spectrometer operating at 14.1 T and equipped with a room-temperature probe (i.e., noncryogenic). Kinetic simulations show that the excellent behavior of FL arises from its long excited-state triplet lifetime and superior photostability relative to conventional photo-CIDNP sensitizers.
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Affiliation(s)
- Yusuke Okuno
- 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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26
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Dale MW, Wedge CJ. Optically generated hyperpolarization for sensitivity enhancement in solution-state NMR spectroscopy. Chem Commun (Camb) 2016; 52:13221-13224. [DOI: 10.1039/c6cc06651h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Using optical excitation to generate radical triplet pairs the sensitivity of solution-state NMR can be enhanced without microwave pumping.
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27
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Eletsky A, Pulavarti SVSRK, Beaumont V, Gollnick P, Szyperski T. Solution NMR Experiment for Measurement of (15)N-(1)H Residual Dipolar Couplings in Large Proteins and Supramolecular Complexes. J Am Chem Soc 2015; 137:11242-5. [PMID: 26293598 DOI: 10.1021/jacs.5b07010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NMR residual dipolar couplings (RDCs) are exquisite probes of protein structure and dynamics. A new solution NMR experiment named 2D SE2 J-TROSY is presented to measure N-H RDCs for proteins and supramolecular complexes in excess of 200 kDa. This enables validation and refinement of their X-ray crystal and solution NMR structures and the characterization of structural and dynamic changes occurring upon complex formation. Accurate N-H RDCs were measured at 750 MHz (1)H resonance frequency for 11-mer 93 kDa (2)H,(15)N-labeled Trp RNA-binding attenuator protein tumbling with a correlation time τc of 120 ns. This is about twice as long as that for the most slowly tumbling system, for which N-H RDCs could be measured, so far, and corresponds to molecular weights of ∼200 kDa at 25 °C. Furthermore, due to the robustness of SE2 J-TROSY with respect to residual (1)H density from exchangeable protons, increased sensitivity at (1)H resonance frequencies around 1 GHz promises to enable N-H RDC measurement for even larger systems.
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Affiliation(s)
- Alexander Eletsky
- Department of Chemistry and ‡Department of Biological Sciences, State University of New York at Buffalo , Buffalo, New York 14260, United States
| | - Surya V S R K Pulavarti
- Department of Chemistry and ‡Department of Biological Sciences, State University of New York at Buffalo , Buffalo, New York 14260, United States
| | - Victor Beaumont
- Department of Chemistry and ‡Department of Biological Sciences, State University of New York at Buffalo , Buffalo, New York 14260, United States
| | - Paul Gollnick
- Department of Chemistry and ‡Department of Biological Sciences, State University of New York at Buffalo , Buffalo, New York 14260, United States
| | - Thomas Szyperski
- Department of Chemistry and ‡Department of Biological Sciences, State University of New York at Buffalo , Buffalo, New York 14260, United States
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28
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Larive CK, Barding GA, Dinges MM. NMR spectroscopy for metabolomics and metabolic profiling. Anal Chem 2014; 87:133-46. [PMID: 25375201 DOI: 10.1021/ac504075g] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Cynthia K Larive
- Department of Chemistry, University of California-Riverside , Riverside, California 92521, United States
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Lee JH, Okuno Y, Cavagnero S. Sensitivity enhancement in solution NMR: emerging ideas and new frontiers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 241:18-31. [PMID: 24656077 PMCID: PMC3967054 DOI: 10.1016/j.jmr.2014.01.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/14/2014] [Accepted: 01/17/2014] [Indexed: 05/05/2023]
Abstract
Modern NMR spectroscopy has reached an unprecedented level of sophistication in the determination of biomolecular structure and dynamics at atomic resolution in liquids. However, the sensitivity of this technique is still too low to solve a variety of cutting-edge biological problems in solution, especially those that involve viscous samples, very large biomolecules or aggregation-prone systems that need to be kept at low concentration. Despite the challenges, a variety of efforts have been carried out over the years to increase sensitivity of NMR spectroscopy in liquids. This review discusses basic concepts, recent developments and future opportunities in this exciting area of research.
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Affiliation(s)
- Jung Ho Lee
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Yusuke Okuno
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Silvia Cavagnero
- Department of Chemistry and Biophysics Program, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA.
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30
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Zhang Y, Soon PC, Jerschow A, Canary JW. Long-Lived1H Nuclear Spin Singlet in Dimethyl Maleate Revealed by Addition of Thiols. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310284] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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31
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Zhang Y, Soon PC, Jerschow A, Canary JW. Long-lived ¹H nuclear spin singlet in dimethyl maleate revealed by addition of thiols. Angew Chem Int Ed Engl 2014; 53:3396-9. [PMID: 24623618 DOI: 10.1002/anie.201310284] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/28/2014] [Indexed: 01/14/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) have become important techniques in many research areas. One major limitation is the relatively low sensitivity of these methods, which recently has been addressed by hyperpolarization. However, once hyperpolarization is imparted on a molecule, the magnetization typically decays within relatively short times. Singlet states are well isolated from the environment, such that they acquire long lifetimes. We describe herein a model reaction for read-out of a hyperpolarized long-lived state in dimethyl maleate using thiol conjugate addition. This type of reaction could lend itself to monitoring oxidative stress or hypoxia by sensitive detection of thiols. Similar reactions could be used in biosensors or assays that exploit molecular switching. Singlet lifetimes of about 4.7 min for (1)H spins in [D4]MeOH are seen in this system.
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Affiliation(s)
- Yuning Zhang
- Department of Chemistry, New York University, 100 Washington Sq. East, New York, NY 10003 (USA) http://www.nyu.edu/projects/jerschow/ http://www.nyu.edu/pages/canary/home.html
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32
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Hyperpolarized NMR probes for biological assays. SENSORS 2014; 14:1576-97. [PMID: 24441771 PMCID: PMC3926627 DOI: 10.3390/s140101576] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 12/20/2013] [Accepted: 01/07/2014] [Indexed: 11/17/2022]
Abstract
During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized) molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.
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Spin hyperpolarization in NMR to address enzymatic processes in vivo. MENDELEEV COMMUNICATIONS 2013. [DOI: 10.1016/j.mencom.2013.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Lumata L, Merritt ME, Kovacs Z. Influence of deuteration in the glassing matrix on 13C dynamic nuclear polarization. Phys Chem Chem Phys 2013; 15:7032-5. [PMID: 23552448 DOI: 10.1039/c3cp50750e] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Replacement of protons by deuterons in the glassing solvents led to 2-3-fold improvement of the (13)C dynamic nuclear polarization (DNP) solid-state NMR signal for samples doped with large electron spin resonance (ESR) linewidth free radicals galvinoxyl, DPPH, and 4-oxo-TEMPO. Meanwhile, the reverse effect is observed for (13)C DNP using small ESR linewidth free radicals BDPA and trityl OX063.
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Affiliation(s)
- Lloyd Lumata
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, USA
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35
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Witte C, Schröder L. NMR of hyperpolarised probes. NMR IN BIOMEDICINE 2013; 26:788-802. [PMID: 23033215 DOI: 10.1002/nbm.2873] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/23/2012] [Accepted: 08/29/2012] [Indexed: 06/01/2023]
Abstract
Increasing the sensitivity of NMR experiments is an ongoing field of research to help realise the exquisite molecular specificity of this technique. Hyperpolarisation of various nuclei is a powerful approach that enables the use of NMR for molecular and cellular imaging. Substantial progress has been achieved over recent years in terms of both tracer preparation and detection schemes. This review summarises recent developments in probe design and optimised signal encoding, and promising results in sensitive disease detection and efficient therapeutic monitoring. The different methods have great potential to provide molecular specificity not available by other diagnostic modalities.
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Affiliation(s)
- Christopher Witte
- ERC Project BiosensorImaging, Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
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Abstract
Nuclear magnetic resonance (NMR) spectroscopy is one of the most commonly used spectroscopic techniques to obtain information on the structure and dynamics of biological and chemical materials. A variety of samples can be studied including solutions, crystalline solids, powders and hydrated protein extracts. However, biological NMR spectroscopy is limited to concentrated samples, typically in the millimolar range, due to its intrinsic low sensitivity compared to other techniques such as fluorescence or electron paramagnetic resonance (EPR) spectroscopy.Dynamic nuclear polarization (DNP) is a method that increases the sensitivity of NMR by several orders of magnitude. It exploits a polarization transfer from unpaired electrons to neighboring nuclei which leads to an absolute increase of the signal-to-noise ratio (S/N). Consequently, biological samples with much lower concentrations can now be studied in hours or days compared to several weeks.This chapter will explain the different types of DNP enhanced NMR experiments, focusing primarily on solid-state magic angle spinning (MAS) DNP, its applications, and possible means of improvement.
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