1
|
Chen B, Fang Z, Zhang Y, Guan X, Lin E, Feng H, Zeng Y, Cai S, Yang Y, Huang Y, Chen Z. Two-Dimensional Laplace NMR Reconstruction through Deep Learning Enhancement. J Am Chem Soc 2024; 146:21591-21599. [PMID: 39046081 DOI: 10.1021/jacs.4c05211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Laplace NMR is a powerful tool for studying molecular dynamics and spin interactions, providing diffusion and relaxation information that complements Fourier NMR used for composition determination and structure elucidation. However, Laplace NMR demands sophisticated signal processing algorithms such as inverse Laplace transform (ILT). Due to the inherently ill-posed nature of ILT problems, it is generally challenging to perform satisfactory Laplace NMR processing and reconstruction, particularly for two-dimensional Laplace NMR. Herein, we propose a proof-of-concept approach that blends a physics-informed strategy with data-driven deep learning for two-dimensional Laplace NMR reconstruction. This approach integrates prior knowledge of mathematical and physical laws governing multidimensional decay signals by constructing a forward process model to simulate relationships among different decay factors. Benefiting from a noniterative neural network algorithm that automatically acquires prior information from synthetic data during training, this approach avoids tedious parameter tuning and enhances user friendliness. Experimental results demonstrate the practical effectiveness of this approach. As an advanced and impactful technique, this approach brings a fresh perspective to multidimensional Laplace NMR inversion.
Collapse
Affiliation(s)
- Bo Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Ze Fang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuebin Zhang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Xun Guan
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Enping Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Hai Feng
- College of Artificial Intelligence, Application Technology Research Center of Artificial Intelligence, Xiamen City University, Xiamen, Fujian 361008, China
| | - Yunsong Zeng
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Shuhui Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yu Yang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuqing Huang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| |
Collapse
|
2
|
Cai TX, Williamson NH, Ravin R, Basser PJ. The Diffusion Exchange Ratio (DEXR): A minimal sampling of diffusion exchange spectroscopy to probe exchange, restriction, and time-dependence. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 366:107745. [PMID: 39126819 DOI: 10.1016/j.jmr.2024.107745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 07/31/2024] [Accepted: 08/02/2024] [Indexed: 08/12/2024]
Abstract
Water exchange is increasingly recognized as an important biological process that can affect the study of biological tissue using diffusion MR. Methods to measure exchange, however, remain immature as opposed to those used to characterize restriction, with no consensus on the optimal pulse sequence (s) or signal model (s). In general, the trend has been towards data-intensive fitting of highly parameterized models. We take the opposite approach and show that a judicious sub-sample of diffusion exchange spectroscopy (DEXSY) data can be used to robustly quantify exchange, as well as restriction, in a data-efficient manner. This sampling produces a ratio of two points per mixing time: (i) one point with equal diffusion weighting in both encoding periods, which gives maximal exchange contrast, and (ii) one point with the same total diffusion weighting in just the first encoding period, for normalization. We call this quotient the Diffusion EXchange Ratio (DEXR). Furthermore, we show that it can be used to probe time-dependent diffusion by estimating the velocity autocorrelation function (VACF) over intermediate to long times (∼2-500ms). We provide a comprehensive theoretical framework for the design of DEXR experiments in the case of static or constant gradients. Data from Monte Carlo simulations and experiments acquired in fixed and viable ex vivo neonatal mouse spinal cord using a permanent magnet system are presented to test and validate this approach. In viable spinal cord, we report the following apparent parameters from just 6 data points: τk=17±4ms, fNG=0.72±0.01, Reff=1.05±0.01μm, and κeff=0.19±0.04μm/ms, which correspond to the exchange time, restricted or non-Gaussian signal fraction, an effective spherical radius, and permeability, respectively. For the VACF, we report a long-time, power-law scaling with ≈t-2.4, which is approximately consistent with disordered domains in 3-D. Overall, the DEXR method is shown to be highly efficient, capable of providing valuable quantitative diffusion metrics using minimal MR data.
Collapse
Affiliation(s)
- Teddy X Cai
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, 20892, MD, USA
| | - Nathan H Williamson
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, 20892, MD, USA
| | - Rea Ravin
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, 20892, MD, USA; Celoptics, Inc., Rockville, 20850, MD, USA
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, 20892, MD, USA.
| |
Collapse
|
3
|
Rotzinger M, Schuster N, Zangger K. Identifying Exchangeable Protons in a 1D NMR Spectrum by Spatially Selective Exchange-Editing. Chemphyschem 2024; 25:e202300713. [PMID: 38407996 DOI: 10.1002/cphc.202300713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 02/28/2024]
Abstract
Signals undergoing chemical or conformational exchange in one-dimensional NMR spectra are often identified by deuterium exchange. In order to obtain quantitative information about the dynamic processes involved, one frequently used method is EXchange SpectroscopY (EXSY). To detect all exchange processes, the EXSY experiment requires the acquisition of time-consuming two-dimensional spectra. Here we report a faster alternative, an experiment which uses spatial encoding to extract similar information in a 1D exchange-edited experiment. Thereby, all protons are observed at once, but in different slices of the detection volume. The experiment can be carried out in a single scan to identify exchanging sites in a 1D spectrum by changes in signal intensity indicating exchange processes. If the exchanging partner, for example water is in molar excess the exchange-editing method easily identifies mobile protons by negative signals in the 1D 1H NMR spectrum.
Collapse
Affiliation(s)
- Markus Rotzinger
- University of Graz, Institute of Chemistry, Heinrichstraße 28, 8010, Graz, Austria
| | - Nathalie Schuster
- University of Graz, Institute of Chemistry, Heinrichstraße 28, 8010, Graz, Austria
| | - Klaus Zangger
- University of Graz, Institute of Chemistry, Heinrichstraße 28, 8010, Graz, Austria
| |
Collapse
|
4
|
Qi C, Mankinen O, Telkki VV, Hilty C. Measuring Protein-Ligand Binding by Hyperpolarized Ultrafast NMR. J Am Chem Soc 2024; 146:5063-5066. [PMID: 38373110 PMCID: PMC10910566 DOI: 10.1021/jacs.3c14359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/06/2024] [Accepted: 02/12/2024] [Indexed: 02/21/2024]
Abstract
Protein-ligand interactions can be detected by observing changes in the transverse relaxation rates of the ligand upon binding. The ultrafast NMR technique, which correlates the chemical shift with the transverse relaxation rate, allows for the simultaneous acquisition of R2 for carbon spins at different positions. In combination with dissolution dynamic nuclear polarization (D-DNP), where the signal intensity is enhanced by thousands of times, the R2 values of several carbon signals from unlabeled benzylamine are observable within a single scan. The hyperpolarized ultrafast chemical shift-R2 correlated experiment separates chemical shift encoding from the readout phase in the NMR pulse sequence, which allows it to beat the fundamental limit on the spectral resolution otherwise imposed by the sampling theorem. Applications enabled by the ability to measure multiple relaxation rates in a single scan include the study of structural properties of protein-ligand interactions.
Collapse
Affiliation(s)
- Chang Qi
- Chemistry
Department, Texas A&M University, College Station, Texas 77843-3255, United
States
| | - Otto Mankinen
- NMR
Research Unit, Faculty of Science, University
of Oulu, 90014 Oulu, Finland
| | - Ville-Veikko Telkki
- NMR
Research Unit, Faculty of Science, University
of Oulu, 90014 Oulu, Finland
| | - Christian Hilty
- Chemistry
Department, Texas A&M University, College Station, Texas 77843-3255, United
States
| |
Collapse
|
5
|
Peat G, Boaler PJ, Dickson CL, Lloyd-Jones GC, Uhrín D. SHARPER-DOSY: Sensitivity enhanced diffusion-ordered NMR spectroscopy. Nat Commun 2023; 14:4410. [PMID: 37479704 PMCID: PMC10361965 DOI: 10.1038/s41467-023-40130-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 07/06/2023] [Indexed: 07/23/2023] Open
Abstract
Since its discovery in mid-20th century, the sensitivity of Nuclear Magnetic Resonance (NMR) has increased steadily, in part due to the design of new, sophisticated NMR experiments. Here we report on a liquid-state NMR methodology that significantly increases the sensitivity of diffusion coefficient measurements of pure compounds, allowing to estimate their sizes using a much reduced amount of material. In this method, the diffusion coefficients are being measured by analysing narrow and intense singlets, which are invariant to magnetic field inhomogeneities. The singlets are obtained through signal acquisition embedded in short (<0.5 ms) spin-echo intervals separated by non-selective 180° or 90° pulses, suppressing the chemical shift evolution of resonances and their splitting due to J couplings. The achieved 10-100 sensitivity enhancement results in a 100-10000-fold time saving. Using high field cryoprobe NMR spectrometers, this makes it possible to measure a diffusion coefficient of a medium-size organic molecule in a matter of minutes with as little as a few hundred nanograms of material.
Collapse
Affiliation(s)
- George Peat
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Rd, Edinburgh, EH9 3FJ, UK
| | - Patrick J Boaler
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Rd, Edinburgh, EH9 3FJ, UK
| | - Claire L Dickson
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Rd, Edinburgh, EH9 3FJ, UK
- Oxford Instruments, Halifax Road, High Wycombe, HP12 3SE2, UK
| | - Guy C Lloyd-Jones
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Rd, Edinburgh, EH9 3FJ, UK
| | - Dušan Uhrín
- EaStCHEM School of Chemistry, University of Edinburgh, David Brewster Rd, Edinburgh, EH9 3FJ, UK.
| |
Collapse
|
6
|
Tolkkinen K, Mailhiot SE, Selent A, Mankinen O, Henschel H, Nieminen MT, Hanni M, Kantola AM, Liimatainen T, Telkki VV. SPICY: a method for single scan rotating frame relaxometry. Phys Chem Chem Phys 2023; 25:13164-13169. [PMID: 37129427 PMCID: PMC10171246 DOI: 10.1039/d2cp05988f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
T 1ρ is an NMR relaxation mode that is sensitive to low frequency molecular motions, making it an especially valuable tool in biomolecular research. Here, we introduce a new method, SPICY, for measuring T1ρ relaxation times. In contrast to conventional T1ρ experiments, in which the sequence is repeated many times to determine the T1ρ time, the SPICY sequence allows determination of T1ρ within a single scan, shortening the experiment time remarkably. We demonstrate the method using 1H T1ρ relaxation dispersion experiments. Additionally, we combine the sequence with spatial encoding to produce 1D images in a single scan. We show that T1ρ relaxation times obtained using the single scan approach are in good agreement with those obtained using the traditional experiments.
Collapse
Affiliation(s)
| | | | - Anne Selent
- NMR Research Unit, University of Oulu, Oulu, Finland.
| | - Otto Mankinen
- NMR Research Unit, University of Oulu, Oulu, Finland.
| | - Henning Henschel
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Miika T Nieminen
- Research Unit of Health Sciences and Technology, University of Oulu, Oulu, Finland
- Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Matti Hanni
- Research Unit of Health Sciences and Technology, University of Oulu, Oulu, Finland
- Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Anu M Kantola
- NMR Research Unit, University of Oulu, Oulu, Finland.
| | - Timo Liimatainen
- Research Unit of Health Sciences and Technology, University of Oulu, Oulu, Finland
- Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | | |
Collapse
|
7
|
Zhan H, Hao M, Lin E, Zheng Z, Huang C, Cai S, Cao S, Huang Y, Chen Z. A Pure Shift-Based Nuclear Magnetic Resonance Method for In-Phase Three-Dimensional Diffusion-Ordered Spectroscopy. Anal Chem 2023; 95:1002-1007. [PMID: 36579454 DOI: 10.1021/acs.analchem.2c03678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY) plays a vital role in mixture studies. However, its applications to complex mixture samples are generally limited by spectral congestion along the chemical shift domain caused by extensive J coupling networks and abundant compounds. Herein, we develop the in-phase multidimensional DOSY strategy for complex mixture analyses by simultaneously revealing molecular self-diffusion behaviors and multiplet structures with optimal spectral resolution. As a proof of concept, two pure shift-based three-dimensional (3D) DOSY protocols are proposed to record high-resolution 3D spectroscopic view with separated mixture components and their resolved multiplet coupling structures, thus suitable for analyzing complex mixtures that contain abundant compounds and complicated molecular structures, even under adverse magnetic field conditions. Therefore, this study shows a promising tool for component analyses and multiplet structure studies on practical mixture samples.
Collapse
Affiliation(s)
- Haolin Zhan
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China.,Department of Biomedical Engineering, Anhui Provincial Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Mengyou Hao
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Enping Lin
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zeyu Zheng
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Chengda Huang
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Shuhui Cai
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Shuohui Cao
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuqing Huang
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| |
Collapse
|
8
|
Maillet B, Sidi-Boulenouar R, Coussot P. Dynamic NMR Relaxometry as a Simple Tool for Measuring Liquid Transfers and Characterizing Surface and Structure Evolution in Porous Media. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15009-15025. [PMID: 36468708 DOI: 10.1021/acs.langmuir.2c01918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Porous media containing voids which can be filled with gas and/or liquids are ubiquitous in our everyday life: soils, wood, bricks, concrete, sponges, and textiles. It is of major interest to identify how a liquid, pushing another fluid or transporting particles, ions, or nutriments, can penetrate or be extracted from the porous medium. High-resolution X-ray microtomography, neutron imaging, and magnetic resonance imaging are techniques allowing us to obtain, in a nondestructive way, a view of the internal processes in nontransparent porous media. Here we review the possibilities of a simple though powerful technique which provides various direct quantitative information on the liquid distribution inside the porous structure and its variations over time due to fluid transport and/or phase changes. It relies on the analysis of the details of the NMR (nuclear magnetic resonance) relaxation of the proton spins of the liquid molecules and its evolution during some process such as the imbibition, drying, or phase change of the sample. This rather cheap technique then allows us to distinguish how the liquid is distributed in the different pore sizes or pore types and how this evolves over time; since the NMR relaxation time depends on the fraction of time spent by the molecule along the solid surface, this technique can also be used to determine the specific surface of some pore classes in the material. The principles of the technique and its contribution to the physical understanding of the processes are illustrated through examples: imbibition, drying or fluid transfers in a nanoporous silica glass, large pores dispersed in a fine polymeric porous matrix, a pile of cellulose fibers partially saturated with bound water, a softwood, and a simple porous inclusion in a cement paste. We thus show the efficiency of the technique to quantify the transfers with a good temporal resolution.
Collapse
Affiliation(s)
- Benjamin Maillet
- Laboratoire Navier (Ecole des Ponts Paris Tech-Université Gustave Eiffel-CNRS), 77420Champs-sur-Marne, France
| | - Rahima Sidi-Boulenouar
- Laboratoire Navier (Ecole des Ponts Paris Tech-Université Gustave Eiffel-CNRS), 77420Champs-sur-Marne, France
| | - Philippe Coussot
- Laboratoire Navier (Ecole des Ponts Paris Tech-Université Gustave Eiffel-CNRS), 77420Champs-sur-Marne, France
| |
Collapse
|
9
|
Ullah MS, Mankinen O, Zhivonitko VV, Telkki VV. Ultrafast transverse relaxation exchange NMR spectroscopy. Phys Chem Chem Phys 2022; 24:22109-22114. [PMID: 36074123 PMCID: PMC9491048 DOI: 10.1039/d2cp02944h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular exchange between different physical or chemical environments occurs due to either diffusion or chemical transformation. Nuclear magnetic resonance (NMR) spectroscopy provides a means of understanding the molecular exchange in a noninvasive way and without tracers. Here, we introduce a novel two dimensional, single-scan ultrafast Laplace NMR (UF LNMR) method to monitor molecular exchange using transverse relaxation as a contrast. The UF T2–T2 relaxation exchange spectroscopy (REXSY) method shortens the experiment time by one to two orders of magnitude compared to its conventional counterpart. Contrary to the conventional EXSY, the exchanging sites are distinguished based on T2 relaxation times instead of chemical shifts, making the method especially useful for systems including physical exchange of molecules. Therefore, the UF REXSY method offers an efficient means for quantification of exchange processes in various fields such as cellular metabolism and ion transport in electrolytes. As a proof of principle, we studied a halogen-free orthoborate based ionic liquid system and followed molecular exchange between molecular aggregates and free molecules. The results are in good agreement with the conventional exchange studies. Due to the single-scan nature, the method potentially significantly facilitates the use of modern hyperpolarization techniques to boost the sensitivity by several orders of magnitude. An ultrafast two-dimensional NMR method allows quantification of molecular exchange rates efficiently based on T2 relaxation contrast.![]()
Collapse
Affiliation(s)
- Md Sharif Ullah
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Otto Mankinen
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Vladimir V Zhivonitko
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Ville-Veikko Telkki
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| |
Collapse
|
10
|
Mamone S, Jagtap AP, Korchak S, Ding Y, Sternkopf S, Glöggler S. A Field‐Independent Method for the Rapid Generation of Hyperpolarized [1‐
13
C]Pyruvate in Clean Water Solutions for Biomedical Applications. Angew Chem Int Ed Engl 2022; 61:e202206298. [PMID: 35723041 PMCID: PMC9543135 DOI: 10.1002/anie.202206298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Salvatore Mamone
- Max Planck Institute for Multidisciplinary Sciences NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG NMR Signal Enhancement Group Von-Siebold-Straße 3 A 37075 Göttingen Germany
| | - Anil P. Jagtap
- Max Planck Institute for Multidisciplinary Sciences NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG NMR Signal Enhancement Group Von-Siebold-Straße 3 A 37075 Göttingen Germany
| | - Sergey Korchak
- Max Planck Institute for Multidisciplinary Sciences NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG NMR Signal Enhancement Group Von-Siebold-Straße 3 A 37075 Göttingen Germany
| | - Yonghong Ding
- Max Planck Institute for Multidisciplinary Sciences NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG NMR Signal Enhancement Group Von-Siebold-Straße 3 A 37075 Göttingen Germany
| | - Sonja Sternkopf
- Max Planck Institute for Multidisciplinary Sciences NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG NMR Signal Enhancement Group Von-Siebold-Straße 3 A 37075 Göttingen Germany
| | - Stefan Glöggler
- Max Planck Institute for Multidisciplinary Sciences NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG NMR Signal Enhancement Group Von-Siebold-Straße 3 A 37075 Göttingen Germany
| |
Collapse
|
11
|
Kharbanda Y, Urbańczyk M, Zhivonitko VV, Mailhiot S, Kettunen MI, Telkki VV. Sensitive, Efficient and Portable Analysis of Molecular Exchange Processes by Hyperpolarized Ultrafast NMR. Angew Chem Int Ed Engl 2022; 61:e202203957. [PMID: 35499690 PMCID: PMC9400989 DOI: 10.1002/anie.202203957] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Indexed: 11/08/2022]
Abstract
Molecular exchange processes are ubiquitous in nature. Here, we introduce a method to analyze exchange processes by using low-cost, portable, single-sided NMR instruments. The inherent magnetic field inhomogeneity of the single-sided instruments is exploited to achieve diffusion contrast of exchange sites and spatial encoding of 2D data. This so-called ultrafast diffusion exchange spectroscopy method shortens the experiment time by two to four orders of magnitude. Furthermore, because full 2D data are measured in a single scan (in a fraction of a second), the sensitivity of the experiment can be improved by several orders of magnitude using so-called nuclear spin hyperpolarization methods (in this case, dissolution dynamic nuclear polarization). As the first demonstration of the feasibility of the method in various applications, we show that the method enables quantification of intra- and extracellular exchange of water in a yeast cell suspension.
Collapse
Affiliation(s)
| | - Mateusz Urbańczyk
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | | | - Sarah Mailhiot
- NMR Research Unit, University of Oulu, Oulu, 90540, Finland
| | - Mikko I Kettunen
- Kuopio Biomedical Imaging Unit, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | | |
Collapse
|
12
|
Mamone S, Jagtap AP, Korchak S, Ding Y, Sternkopf S, Glöggler S. A Field‐Independent Method for the Rapid Generation of Hyperpolarized [1‐13C]Pyruvate in Clean Water Solutions for Biomedical Applications. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Salvatore Mamone
- Max Planck Institute for Multidisciplinary Sciences - Fassberg Campus: Max-Planck-Institut fur Multidisziplinare Naturwissenschaften NMR Signal Enhancement GERMANY
| | - Anil P Jagtap
- Max Planck Institute for Multidisciplinary Sciences: Max-Planck-Institut fur Multidisziplinare Naturwissenschaften NMR Signal Enhancement GERMANY
| | - Sergey Korchak
- Max Planck Institute for Multidisciplinary Sciences: Max-Planck-Institut fur Multidisziplinare Naturwissenschaften NMR Signal Enhancement GERMANY
| | - Yonghong Ding
- Max Planck Institute for Multidisciplinary Sciences: Max-Planck-Institut fur Multidisziplinare Naturwissenschaften NMR Signal Enhancement GERMANY
| | - Sonja Sternkopf
- Max Planck Institute for Multidisciplinary Sciences: Max-Planck-Institut fur Multidisziplinare Naturwissenschaften NMR Signal Enhancement GERMANY
| | - Stefan Glöggler
- Max-Planck-Institute for Biophysical Chemistry NMR Signal Enhancement Group Am Fassberg 11 37077 Göttingen GERMANY
| |
Collapse
|
13
|
Mames A, Jopa S, Pietrzak M, Ratajczyk T. Deactivation of catalysts in simultaneous reversible and irreversible parahydrogen NMR signal enhancement, and the role of co-ligands in the stabilization of the reversible method. RSC Adv 2022; 12:15986-15991. [PMID: 35733673 PMCID: PMC9136854 DOI: 10.1039/d2ra02872g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 05/23/2022] [Indexed: 11/21/2022] Open
Abstract
Signal Amplification by Reversible Exchange (SABRE) and hydrogeneable Parahydrogen Induced Polarization (hPHIP) can enhance weak NMR signals, and thus increase the range of NMR applications. Here, using an N-heterocyclic carbene Ir-based catalyst, simultaneous SABRE and hPHIP was achieved for the compound with an N-donor site and an acetylene triple bond. It was demonstrated that the interplay between SABRE and hPHIP can be manipulated. Specifically, it was found that the hPHIP effect could be almost completely suppressed, while stable SABRE was observed in subsequent consecutive experiments. The presented results have the potential to increase the numbers of parahydrogen hyperpolarizable molecules.
Collapse
Affiliation(s)
- Adam Mames
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 Warsaw 01-224 Poland
| | - Sylwia Jopa
- Faculty of Chemistry, University of Warsaw Pasteura 1 Warsaw 02-093 Poland
| | - Mariusz Pietrzak
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 Warsaw 01-224 Poland
| | - Tomasz Ratajczyk
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 Warsaw 01-224 Poland
| |
Collapse
|
14
|
Kharbanda Y, Urbańczyk M, Zhivonitko VV, Mailhiot S, Kettunen MI, Telkki V. Sensitive, Efficient and Portable Analysis of Molecular Exchange Processes by Hyperpolarized Ultrafast NMR. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Mateusz Urbańczyk
- Institute of Physical Chemistry Polish Academy of Sciences Warsaw Poland
| | | | | | - Mikko I. Kettunen
- Kuopio Biomedical Imaging Unit A.I. Virtanen Institute for Molecular Sciences University of Eastern Finland Kuopio Finland
| | | |
Collapse
|
15
|
Robinson N, May EF, Johns ML. Low-Field Functional Group Resolved Nuclear Spin Relaxation in Mesoporous Silica. ACS APPLIED MATERIALS & INTERFACES 2021; 13:54476-54485. [PMID: 34743514 DOI: 10.1021/acsami.1c13934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Solid-fluid interactions underpin the efficacy of functional porous materials across a diverse array of chemical reaction and separation processes. However, detailed characterization of interfacial phenomena within such systems is hampered by their optically opaque nature. Motivated by the need to bridge this capability gap, we report low-magnetic-field two-dimensional (2D) 1H nuclear spin relaxation measurements as a noninvasive probe of adsorbate identity and interfacial dynamics, exploring the relaxation characteristics exhibited by liquid hydrocarbon adsorbates confined to a model mesoporous silica. For the first time, we demonstrate the capacity of this approach in distinguishing functional group-specific relaxation phenomena across a diverse range of alcohols and carboxylic acids employed as solvents, reagents, and liquid hydrogen carriers, with distinct relaxation responses assigned to the alkyl and hydroxyl moieties of each confined liquid. Uniquely, this relaxation behavior is shown to correlate with adsorbate acidity, with the observed relationship rationalized on the basis of surface-adsorbate proton-exchange dynamics. Our results demonstrate that nuclear spin relaxation provides a molecular-level perspective on sorbent/sorbate interactions, motivating the exploration of such measurements as a unique probe of adsorbate identity within optically opaque porous media.
Collapse
Affiliation(s)
- Neil Robinson
- Department of Chemical Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Eric F May
- Department of Chemical Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Michael L Johns
- Department of Chemical Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| |
Collapse
|
16
|
Telkki VV, Urbańczyk M, Zhivonitko V. Ultrafast methods for relaxation and diffusion. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 126-127:101-120. [PMID: 34852922 DOI: 10.1016/j.pnmrs.2021.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Relaxation and diffusion NMR measurements offer an approach to studying rotational and translational motion of molecules non-invasively, and they also provide chemical resolution complementary to NMR spectra. Multidimensional experiments enable the correlation of relaxation and diffusion parameters as well as the observation of molecular exchange phenomena through relaxation or diffusion contrast. This review describes how to accelerate multidimensional relaxation and diffusion measurements significantly through spatial encoding. This so-called ultrafast Laplace NMR approach shortens the experiment time to a fraction and makes even single-scan experiments possible. Single-scan experiments, in turn, significantly facilitate the use of nuclear spin hyperpolarization methods to boost sensitivity. The ultrafast Laplace NMR method is also applicable with low-field, mobile NMR instruments, and it can be exploited in many disciplines. For example, it has been used in studies of the dynamics of fluids in porous materials, identification of intra- and extracellular metabolites in cancer cells, and elucidation of aggregation phenomena in atmospheric surfactant solutions.
Collapse
Affiliation(s)
| | - Mateusz Urbańczyk
- NMR Research Unit, University of Oulu, P.O. Box 3000, FIN-90014, Finland; Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | | |
Collapse
|
17
|
Cohen Y, Slovak S, Avram L. Solution NMR of synthetic cavity containing supramolecular systems: what have we learned on and from? Chem Commun (Camb) 2021; 57:8856-8884. [PMID: 34486595 DOI: 10.1039/d1cc02906a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
NMR has been instrumental in studies of both the structure and dynamics of molecular systems for decades, so it is not surprising that NMR has played a pivotal role in the study of host-guest complexes and supramolecular systems. In this mini-review, selected examples will be used to demonstrate the added value of using (multiparametric) NMR for studying macrocycle-based host-guest and supramolecular systems. We will restrict the discussion to synthetic host systems having a cavity that can engulf their guests thus restricting them into confined spaces. So discussion of selected examples of cavitands, cages, capsules and their complexes, aggregates and polymers as well as organic cages and porous liquids and other porous materials will be used to demonstrate the insights that have been gathered from the extracted NMR parameters when studying such systems emphasizing the information obtained from somewhat less routine NMR methods such as diffusion NMR, diffusion ordered spectroscopy (DOSY) and chemical exchange saturation transfer (CEST) and their variants. These selected examples demonstrate the impact that the results and findings from these NMR studies have had on our understanding of such systems and on the developments in various research fields.
Collapse
Affiliation(s)
- Yoram Cohen
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 699781, Tel Aviv, Israel.
| | - Sarit Slovak
- School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 699781, Tel Aviv, Israel.
| | - Liat Avram
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot 7610001, Israel
| |
Collapse
|
18
|
Tickner BJ, Zhivonitko VV, Telkki VV. Ultrafast Laplace NMR to study metal-ligand interactions in reversible polarisation transfer from parahydrogen. Phys Chem Chem Phys 2021; 23:16542-16550. [PMID: 34338685 PMCID: PMC8359933 DOI: 10.1039/d1cp02383g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/22/2021] [Indexed: 12/11/2022]
Abstract
Laplace Nuclear Magnetic Resonance (NMR) can determine relaxation parameters and diffusion constants, giving valuable information about molecular structure and dynamics. Information about relaxation times (T1 and T2) and the self-diffusion coefficient (D) can be extracted from exponentially decaying NMR signals by performing a Laplace transform, which is a different approach to traditional NMR involving Fourier transform of a free induction decay. Ultrafast Laplace NMR uses spatial encoding to collect the entire data set in just a single scan which provides orders of magnitude time savings. In this work we use ultrafast Laplace NMR D-T2 correlation sequences to measure key relaxation (T2) and diffusion (D) parameters of methanolic solutions containing pyridine. For the first time we combine this technique with the hyperpolarisation technique Signal Amplification By Reversible Exchange (SABRE), which employs an iridium catalyst to reversibly transfer polarisation from parahydrogen, to boost the 1H NMR signals of pyridine by up to 300-fold. We demonstrate use of ultrafast Laplace NMR to monitor changes in pyridine T2 and D associated with ligation to the iridium SABRE catalyst and kinetic isotope exchange reactions. The combined 1440-fold reduction in experiment time and 300-fold 1H NMR signal enhancement allow the determination of pyridine D coefficients and T2 values at 25 mM concentrations in just 3 seconds using SABRE hyperpolarised ultrafast Laplace NMR.
Collapse
Affiliation(s)
- Ben. J. Tickner
- NMR Research Unit, Faculty of Science, University of Oulu90014Finland
| | | | | |
Collapse
|
19
|
Lin E, Telkki VV, Lin X, Huang C, Zhan H, Yang Y, Huang Y, Chen Z. High-Resolution Reconstruction for Multidimensional Laplace NMR. J Phys Chem Lett 2021; 12:5085-5090. [PMID: 34028285 PMCID: PMC8397344 DOI: 10.1021/acs.jpclett.1c01022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
As a perfect complement to conventional NMR that aims for chemical structure elucidation, Laplace NMR constitutes a powerful technique to study spin relaxation and diffusion, revealing information on molecular motions and spin interactions. Different from conventional NMR adopting Fourier transform to deal with the acquired data, Laplace NMR relies on specially designed signal processing and reconstruction algorithms resembling the inverse Laplace transform, and it generally faces severe challenges in cases where high spectral resolution and high spectral dimensionality are required. Herein, based on the tensor technique for high-dimensional problems and the sparsity assumption, we propose a general method for high-resolution reconstruction of multidimensional Laplace NMR data. We show that the proposed method can reconstruct multidimensional Laplace NMR spectra in a high-resolution manner for exponentially decaying relaxation and diffusion data acquired by commercial NMR instruments. Therefore, it would broaden the scope of multidimensional Laplace NMR applications.
Collapse
Affiliation(s)
- Enping Lin
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Ville-Veikko Telkki
- NMR
Research Unit, University of Oulu, P.O. Box 3000, Oulu FIN-90014, Finland
| | - Xiaoqing Lin
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Chengda Huang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Haolin Zhan
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yu Yang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuqing Huang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| |
Collapse
|
20
|
Ullah MS, Zhivonitko VV, Samoylenko A, Zhyvolozhnyi A, Viitala S, Kankaanpää S, Komulainen S, Schröder L, Vainio SJ, Telkki VV. Identification of extracellular nanoparticle subsets by nuclear magnetic resonance. Chem Sci 2021; 12:8311-8319. [PMID: 34221312 PMCID: PMC8221169 DOI: 10.1039/d1sc01402a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/29/2021] [Indexed: 01/08/2023] Open
Abstract
Exosomes are a subset of secreted lipid envelope-encapsulated extracellular vesicles (EVs) of 50-150 nm diameter that can transfer cargo from donor to acceptor cells. In the current purification protocols of exosomes, many smaller and larger nanoparticles such as lipoproteins, exomers and microvesicles are typically co-isolated as well. Particle size distribution is one important characteristics of EV samples, as it reflects the cellular origin of EVs and the purity of the isolation. However, most of the physicochemical analytical methods today cannot illustrate the smallest exosomes and other small particles like the exomers. Here, we demonstrate that diffusion ordered spectroscopy (DOSY) nuclear magnetic resonance (NMR) method enables the determination of a very broad distribution of extracellular nanoparticles, ranging from 1 to 500 nm. The range covers sizes of all particles included in EV samples after isolation. The method is non-invasive, as it does not require any labelling or other chemical modification. We investigated EVs secreted from milk as well as embryonic kidney and renal carcinoma cells. Western blot analysis and immuno-electron microscopy confirmed expression of exosomal markers such as ALIX, TSG101, CD81, CD9, and CD63 in the EV samples. In addition to the larger particles observed by nanoparticle tracking analysis (NTA) in the range of 70-500 nm, the DOSY distributions include a significant number of smaller particles in the range of 10-70 nm, which are visible also in transmission electron microscopy images but invisible in NTA. Furthermore, we demonstrate that hyperpolarized chemical exchange saturation transfer (Hyper-CEST) with 129Xe NMR indicates also the existence of smaller and larger nanoparticles in the EV samples, providing also additional support for DOSY results. The method implies also that the Xe exchange is significantly faster in the EV pool than in the lipoprotein/exomer pool.
Collapse
Affiliation(s)
| | | | - Anatoliy Samoylenko
- Laboratory of Developmental Biology, Infotech Oulu, Oulu Center for Cell-Matrix Research, Kvantum Institute, Faculty of Biochemistry and Molecular Medicine Oulu Finland
| | - Artem Zhyvolozhnyi
- Laboratory of Developmental Biology, Infotech Oulu, Oulu Center for Cell-Matrix Research, Kvantum Institute, Faculty of Biochemistry and Molecular Medicine Oulu Finland
| | - Sirja Viitala
- Production Systems, Natural Resources Institute Finland (Luke) Jokioinen Finland
| | - Santeri Kankaanpää
- Production Systems, Natural Resources Institute Finland (Luke) Jokioinen Finland
| | | | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Berlin Germany
- Division of Translational Molecular Imaging, German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Seppo J Vainio
- Laboratory of Developmental Biology, Infotech Oulu, Oulu Center for Cell-Matrix Research, Kvantum Institute, Faculty of Biochemistry and Molecular Medicine Oulu Finland
| | | |
Collapse
|
21
|
Urbańczyk M, Kharbanda Y, Mankinen O, Telkki VV. Accelerating Restricted Diffusion NMR Studies with Time-Resolved and Ultrafast Methods. Anal Chem 2020; 92:9948-9955. [PMID: 32551510 PMCID: PMC7439255 DOI: 10.1021/acs.analchem.0c01523] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Restricted
diffusion of fluids in porous materials can be studied
by pulsed field gradient nuclear magnetic resonance (NMR) non-invasively
and without tracers. If the experiment is repeated many times with
varying diffusion delays, detailed information about pore sizes and
tortuosity can be recorded. However, the measurements are very time-consuming
because numerous repetitions are needed for gradient ramping and varying
diffusion delays. In this paper, we demonstrate two different strategies
for acceleration of the restricted diffusion NMR measurements: time-resolved
diffusion NMR and ultrafast Laplace NMR. The former is based on time-resolved
non-uniform sampling, while the latter relies on spatial encoding
of two-dimensional data. Both techniques allow similar 1–2
order of magnitude acceleration of acquisition, but they have different
strengths and weaknesses, which we discuss in detail. The feasibility
of the methods was proven by investigating restricted diffusion of
water inside tracheid cells of thermally modified pine wood.
Collapse
Affiliation(s)
| | | | - Otto Mankinen
- NMR Research Unit, University of Oulu, 90014 Oulu, Finland.,Oulu Functional NeuroImaging Group, Research Unit of Medical Imaging, Physics and Technology, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, 90029 Oulu, Finland
| | | |
Collapse
|