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Gomez MV, Baas S, Velders AH. Multinuclear 1D and 2D NMR with 19F-Photo-CIDNP hyperpolarization in a microfluidic chip with untuned microcoil. Nat Commun 2023; 14:3885. [PMID: 37391397 DOI: 10.1038/s41467-023-39537-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 06/14/2023] [Indexed: 07/02/2023] Open
Abstract
Nuclear Magnetic Resonance (NMR) spectroscopy is a most powerful molecular characterization and quantification technique, yet two major persistent factors limit its more wide-spread applications: poor sensitivity, and intricate complex and expensive hardware required for sophisticated experiments. Here we show NMR with a single planar-spiral microcoil in an untuned circuit with hyperpolarization option and capability to execute complex experiments addressing simultaneously up to three different nuclides. A microfluidic NMR-chip in which the 25 nL detection volume can be efficiently illuminated with laser-diode light enhances the sensitivity by orders of magnitude via photochemically induced dynamic nuclear polarization (photo-CIDNP), allowing rapid detection of samples in the lower picomole range (normalized limit of detection at 600 MHz, nLODf,600, of 0.01 nmol Hz1/2). The chip is equipped with a single planar microcoil operating in an untuned circuit that allows different Larmor frequencies to be addressed simultaneously, permitting advanced hetero-, di- and trinuclear, 1D and 2D NMR experiments. Here we show NMR chips with photo-CIDNP and broadband capabilities addressing two of the major limiting factors of NMR, by enhancing sensitivity as well as reducing cost and hardware complexity; the performance is compared to state-of-the-art instruments.
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Affiliation(s)
- M Victoria Gomez
- IRICA, Department of Inorganic, Organic and Biochemistry, Faculty of Chemical Sciences and Technologies, Universidad de Castilla-La Mancha (UCLM), Av. Camilo José Cela 10, 13071, Ciudad Real, Spain.
| | - Sander Baas
- Laboratory of BioNanoTechnology, Wageningen University, 6700 EK, Wageningen, The Netherlands
| | - Aldrik H Velders
- IRICA, Department of Inorganic, Organic and Biochemistry, Faculty of Chemical Sciences and Technologies, Universidad de Castilla-La Mancha (UCLM), Av. Camilo José Cela 10, 13071, Ciudad Real, Spain.
- Laboratory of BioNanoTechnology, Wageningen University, 6700 EK, Wageningen, The Netherlands.
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2
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Wong A. A roadmap to high-resolution standard microcoil MAS NMR spectroscopy for metabolomics. NMR IN BIOMEDICINE 2023; 36:e4683. [PMID: 34970795 DOI: 10.1002/nbm.4683] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/06/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Current microcoil probe technology has emerged as a significant advancement in NMR applications to biofluids research. It has continued to excel as a hyphenated tool with other prominent microdevices, opening many new possibilities in multiple omics fields. However, this does not hold for biological samples such as intact tissue or organisms, due to the considerable challenges of incorporating the microcoil in a magic-angle spinning (MAS) probe without relinquishing the high-resolution spectral data. Not until 2012 did a microcoil MAS probe show promise in profiling the metabolome in a submilligram tissue biopsy with spectral resolution on par with conventional high-resolution MAS (HR-MAS) NMR. This result subsequently triggered a great interest in the possibility of NMR analysis with microgram tissues and striving toward the probe development of "high-resolution" capable microcoil MAS NMR spectroscopy. This review gives an overview of the issues and challenges in the probe development and summarizes the advancements toward metabolomics.
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Affiliation(s)
- Alan Wong
- NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay, Gif-sur-Yvette, France
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3
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Zhang Y, Andrén OCJ, Nordström R, Fan Y, Malmsten M, Mongkhontreerat S, Malkoch M. Off-Stoichiometric Thiol-Ene Chemistry to Dendritic Nanogel Therapeutics. ADVANCED FUNCTIONAL MATERIALS 2019; 29:1806693. [PMID: 35865651 PMCID: PMC9286377 DOI: 10.1002/adfm.201806693] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/28/2019] [Indexed: 05/03/2023]
Abstract
A novel platform of dendritic nanogels is herein presented, capitalizing on the self-assembly of allyl-functional polyesters based on dendritic-linear-dendritic amphiphiles followed by simple cross-linking with complementary monomeric thiols via UV initiated off-stoichiometric thiol-ene chemistry. The facile approach enabled multigram creation of allyl reactive nanogel precursors, in the size range of 190-295 nm, being readily available for further modifications to display a number of core functionalities while maintaining the size distribution and characteristics of the master batch. The nanogels are evaluated as carriers of a spread of chemotherapeutics by customizing the core to accommodate each individual cargo. The resulting nanogels are biocompatible, displaying diffusion controlled release of cargo, maintained therapeutic efficacy, and decreased cargo toxic side effects. Finally, the nanogels are found to successfully deliver pharmaceuticals into a 3D pancreatic spheroids tumor model.
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Affiliation(s)
- Yuning Zhang
- KTH Royal Institute of TechnologyDepartment of Fibre and Polymer TechnologySE‐100 44StockholmSweden
| | - Oliver C. J. Andrén
- KTH Royal Institute of TechnologyDepartment of Fibre and Polymer TechnologySE‐100 44StockholmSweden
| | - Randi Nordström
- Department of PharmacyUppsala UniversitySE‐751 23UppsalaSweden
| | - Yanmiao Fan
- KTH Royal Institute of TechnologyDepartment of Fibre and Polymer TechnologySE‐100 44StockholmSweden
| | - Martin Malmsten
- Department of PharmacyUppsala UniversitySE‐751 23UppsalaSweden
| | | | - Michael Malkoch
- KTH Royal Institute of TechnologyDepartment of Fibre and Polymer TechnologySE‐100 44StockholmSweden
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4
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Fang Y, Yushmanov PV, Furó I. Assessing 2D electrophoretic mobility spectroscopy (2D MOSY) for analytical applications. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:584-588. [PMID: 27930812 PMCID: PMC5434926 DOI: 10.1002/mrc.4558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 06/06/2023]
Abstract
Electrophoretic displacement of charged entity phase modulates the spectrum acquired in electrophoretic NMR experiments, and this modulation can be presented via 2D FT as 2D mobility spectroscopy (MOSY) spectra. We compare in various mixed solutions the chemical selectivity provided by 2D MOSY spectra with that provided by 2D diffusion-ordered spectroscopy (DOSY) spectra and demonstrate, under the conditions explored, a superior performance of the former method. 2D MOSY compares also favourably with closely related LC-NMR methods. The shape of 2D MOSY spectra in complex mixtures is strongly modulated by the pH of the sample, a feature that has potential for areas such as in drug discovery and metabolomics. Copyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.
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Affiliation(s)
- Yuan Fang
- Division of Applied Physical Chemistry, Department of ChemistryKTH Royal Institute of TechnologyTeknikringen 30SE‐10044StockholmSweden
| | | | - István Furó
- Division of Applied Physical Chemistry, Department of ChemistryKTH Royal Institute of TechnologyTeknikringen 30SE‐10044StockholmSweden
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5
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Mahrous EA, Farag MA. Two dimensional NMR spectroscopic approaches for exploring plant metabolome: A review. J Adv Res 2014; 6:3-15. [PMID: 25685540 PMCID: PMC4293671 DOI: 10.1016/j.jare.2014.10.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 10/09/2014] [Accepted: 10/11/2014] [Indexed: 01/06/2023] Open
Abstract
Today, most investigations of the plant metabolome tend to be based on either nuclear magnetic resonance (NMR) spectroscopy or mass spectrometry (MS), with or without hyphenation with chromatography. Although less sensitive than MS, NMR provides a powerful complementary technique for the identification and quantification of metabolites in plant extracts. NMR spectroscopy, well appreciated by phytochemists as a particularly information-rich method, showed recent paradigm shift for the improving of metabolome(s) structural and functional characterization and for advancing the understanding of many biological processes. Furthermore, two dimensional NMR (2D NMR) experiments and the use of chemometric data analysis of NMR spectra have proven highly effective at identifying novel and known metabolites that correlate with changes in genotype or phenotype. In this review, we provide an overview of the development of NMR in the field of metabolomics with special focus on 2D NMR spectroscopic techniques and their applications in phytomedicines quality control analysis and drug discovery from natural sources, raising more attention at its potential to reduce the gap between the pace of natural products research and modern drug discovery demand.
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Affiliation(s)
- Engy A Mahrous
- Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, Kasr el Aini st. P.B. 11562, Egypt
| | - Mohamed A Farag
- Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, Kasr el Aini st. P.B. 11562, Egypt
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6
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Webb AG. Radiofrequency microcoils for magnetic resonance imaging and spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 229:55-66. [PMID: 23142002 DOI: 10.1016/j.jmr.2012.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 10/07/2012] [Accepted: 10/09/2012] [Indexed: 06/01/2023]
Abstract
Small radiofrequency coils, often termed "microcoils", have found extensive use in many areas of magnetic resonance. Their advantageous properties include a very high intrinsic sensitivity, a high (several MHz) excitation and reception bandwidth, the fact that large arrays can fit within the homogeneous volume of the static magnetic field, and the very high resonance frequencies (several GHz) that can be achieved. This review concentrates on recent developments in the construction of single and multiple RF microcoil systems, and new types of experiments that can be performed using such assemblies.
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Affiliation(s)
- A G Webb
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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7
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Wolfender JL, Queiroz EF, Hostettmann K. The importance of hyphenated techniques in the discovery of new lead compounds from nature. Expert Opin Drug Discov 2013; 1:237-60. [PMID: 23495845 DOI: 10.1517/17460441.1.3.237] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nature represents an extraordinary reservoir of novel molecules and there is currently a resurgence of interest in natural products as a possible source of new lead compounds for introduction into therapeutical screening programmes. To discover new bioactive natural products, the dereplication of crude extracts performed prior to isolation work is of crucial importance for avoiding the tedious isolation of known constituents. In this respect, chemical screening strategies based on hyphenated techniques such as liquid chromatography-ultraviolet photodiode array detection, liquid chromatography-mass spectrometry, liquid chromatography tandom mass spectrometry and liquid chromatography-nuclear magnetic resonance (LC-NMR) are more and more extensively used. In the laboratory of Hostettmann's group, these analytical methods have been fully integrated into the isolation process and are used for the chemical screening of crude plant extracts, in complement with online or at-line bioassays, for rapid localisation and identification of new bioactive compounds. In this paper, possibilities and limitations of hyphenated techniques for de novo online natural product identification are discussed. As LC-NMR is playing a key role in this respect, the main part of the paper is dedicated to this technique. In particular, various ways of integrating NMR in the dereplication process are illustrated and strategies involving either direct or indirect hyphenation are presented.
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Affiliation(s)
- Jean-Luc Wolfender
- Laboratory of Pharmacognosy and Pytochemistry, School of Pharmaceutical Sciences, University of Geneva, Univerity of Lausanne, 30 quai Ernest-Ansermet, CH-1211, Geneva, Switzerland; †
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8
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Ryan H, Song SH, Zaß A, Korvink J, Utz M. Contactless NMR Spectroscopy on a Chip. Anal Chem 2012; 84:3696-702. [DOI: 10.1021/ac300204z] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Herbert Ryan
- Department
of Mechanical and Aeropspace Engineering, University of Virginia, Charlottesville, Virginia 22904, United
States
| | - Suk-Heung Song
- Department
of Mechanical and Aeropspace Engineering, University of Virginia, Charlottesville, Virginia 22904, United
States
| | - Anja Zaß
- Department of Microsystems
Engineering, University of Freiburg, Germany
| | - Jan Korvink
- Department of Microsystems
Engineering, University of Freiburg, Germany
- Freiburg Institute for Advanced Studies, Germany
| | - Marcel Utz
- Department
of Mechanical and Aeropspace Engineering, University of Virginia, Charlottesville, Virginia 22904, United
States
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United
States
- Center For Microsystems
For The Life Sciences, University of Virginia, Charlottesville, Virginia 22904, United States
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9
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From single to multiple microcoil flow probe NMR and related capillary techniques: a review. Anal Bioanal Chem 2011; 402:647-69. [PMID: 21969176 DOI: 10.1007/s00216-011-5419-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 08/20/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is one of the most important and powerful instrumental analytical techniques for structural elucidation of unknown small and large (complex) isolated and synthesized compounds in organic and inorganic chemistry. X-ray crystallography, neutron scattering (neutron diffraction), and NMR spectroscopy are the only suitable methods for three-dimensional structure determination at atomic resolution. Moreover, these methods are complementary. However, by means of NMR spectroscopy, reaction dynamics and interaction processes can also be investigated. Unfortunately, this technique is very insensitive in comparison with other spectrometric (e.g., mass spectrometry) and spectroscopic (e.g., infrared spectroscopy) methods. Mainly through the development of stronger magnets and more sensitive solenoidal microcoil flow probes, this drawback has been successfully counteracted. Capillary NMR spectroscopy increases the mass-based sensitivity of the NMR spectroscopic analysis up to 100-fold compared with conventional 5-mm NMR probes, and thus can be coupled online and off-line with other microseparation and detection techniques. It offers not only higher sensitivity, but in many cases provides better quality spectra than traditional methods. Owing to the immense number of compounds (e.g., of natural product extracts and compound libraries) to be examined, single microcoil flow probe NMR spectroscopy will soon be far from being sufficiently effective as a screening method. For this reason, an inevitable trend towards coupled microseparation-multiple microcoil flow probe NMR techniques, which allow simultaneous online and off-line detection of several compounds, will occur. In this review we describe the current status and possible future developments of single and multiple microcoil capillary flow probe NMR spectroscopy and its application as a high-throughput tool for the analysis of a large number of mass-limited samples. The advantages and drawbacks of different coupled microseparation-capillary NMR spectroscopy techniques, such as capillary high-performance liquid chromatography-NMR spectroscopy, capillary electrophoresis-NMR spectroscopy, and capillary gas chromatography-NMR spectroscopy, are discussed and demonstrated by specific applications. Another subject of discussion is the progress in parallel NMR detection techniques. Furthermore, the applicability and mixing capability of tiny reactor systems, termed "microreactors" or "micromixers," implemented in NMR probes is demonstrated by carbamate- and imine-forming reactions.
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10
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Teisseyre TZ, Urban J, Halpern-Manners NW, Chambers SD, Bajaj VS, Svec F, Pines A. Remotely Detected NMR for the Characterization of Flow and Fast Chromatographic Separations Using Organic Polymer Monoliths. Anal Chem 2011; 83:6004-10. [DOI: 10.1021/ac2010108] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas Z. Teisseyre
- Program in Bioengineering, University of California—Berkeley and University of California—San Francisco, California 94133, United States
| | - Jiri Urban
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
| | | | - Stuart D. Chambers
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Vikram S. Bajaj
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
| | | | - Alexander Pines
- Department of Chemistry, University of California—Berkeley, Berkeley, California 94720, United States
- Program in Bioengineering, University of California—Berkeley and University of California—San Francisco, California 94133, United States
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11
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Diekmann J, Adams KL, Klunder GL, Evans L, Steele P, Vogt C, Herberg JL. Portable Microcoil NMR Detection Coupled to Capillary Electrophoresis. Anal Chem 2011; 83:1328-35. [DOI: 10.1021/ac102389b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joana Diekmann
- Department of Analytical Chemistry, Institute of Inorganic Chemistry, Faculty of Natural Sciences, Leibniz University Hanover, Callinstrasse 1, 30167 Hanover, Germany
| | - Kristl L. Adams
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - Gregory L. Klunder
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - Lee Evans
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - Paul Steele
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - Carla Vogt
- Department of Analytical Chemistry, Institute of Inorganic Chemistry, Faculty of Natural Sciences, Leibniz University Hanover, Callinstrasse 1, 30167 Hanover, Germany
| | - Julie L. Herberg
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
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12
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Fratila RM, Velders AH. Small-volume nuclear magnetic resonance spectroscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2011; 4:227-249. [PMID: 21391818 DOI: 10.1146/annurev-anchem-061010-114024] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is one of the most information-rich analytical techniques available. However, it is also inherently insensitive, and this drawback precludes the application of NMR spectroscopy to mass- and volume-limited samples. We review a particular approach to increase the sensitivity of NMR experiments, namely the use of miniaturized coils. When the size of the coil is reduced, the sample volume can be brought down to the nanoliter range. We compare the main coil geometries (solenoidal, planar, and microslot/stripline) and discuss their applications to the analysis of mass-limited samples. We also provide an overview of the hyphenation of microcoil NMR spectroscopy to separation techniques and of the integration with lab-on-a-chip devices and microreactors.
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Affiliation(s)
- Raluca M Fratila
- MIRA Institute for Biomedical Engineering and Technical Medicine, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands.
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13
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Neuberger T, Webb A. Radiofrequency coils for magnetic resonance microscopy. NMR IN BIOMEDICINE 2009; 22:975-981. [PMID: 18300326 DOI: 10.1002/nbm.1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Given the several orders of magnitude fewer spins per voxel for MR microscopy than for conventional MRI, efficient coil design is important to obtain sufficient signal-to-noise within reasonable data acquisition times. As MR microscopy is typically performed using very high magnetic fields, coil design must also incorporate the effects of increased component losses and skin-depth-dependent resistance, as well as radiation losses and phase effects for coils when conductor dimensions constitute a substantial fraction of the electromagnetic wavelength. For samples much less than 1 mm in size, wire solenoids or microfabricated planar coils are used. For samples with diameters of several millimeters, saddle, birdcage, Alderman-Grant or millipede coils become the preferred choice. Recent advances in multiple-coil probes and phased arrays have been used to reduce data acquisition time and/or increase sample throughput, and small superconducting coils have shown significant improvements in signal-to-noise over equivalently sized room-temperature coils.
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Affiliation(s)
- Thomas Neuberger
- Department of Bioengineering, Pennsylvania State University, University Park, PA, USA
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14
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Utz M, Monazami R. Nuclear magnetic resonance in microfluidic environments using inductively coupled radiofrequency resonators. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 198:132-136. [PMID: 19237303 DOI: 10.1016/j.jmr.2009.01.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 01/08/2009] [Accepted: 01/22/2009] [Indexed: 05/27/2023]
Abstract
Inductively coupled radiofrequency resonators can provide NMR signals from small samples wirelessly and with high sensitivity. We explore the achievable sensitivity depending on the resonator's Q-factor and its cross-inductance to the NMR probe. Even for small resonators with modest Q, the sensitivity can be close to that of directly (impedance) coupled microcoils. Sensitivity and excitation power inside inductively coupled solenoids were monitored experimentally by microimaging. The flow velocity profile inside a capillary of 200microm diameter was measured with a resolution and sensitivity that rivals recent work based on directly coupled microcoils.
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Affiliation(s)
- Marcel Utz
- Center For Microsystems For The Life Sciences, University of Virginia, Charlottesville, VA 22904, USA.
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15
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Bergeron SJ, Henry ID, Santini RE, Aghdasi A, Raftery D. Saturation transfer double-difference NMR spectroscopy using a dual solenoid microcoil difference probe. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2008; 46:925-9. [PMID: 18615852 PMCID: PMC5441454 DOI: 10.1002/mrc.2275] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
An experiment designed to collect a saturation transfer double difference (STDD) NMR spectrum using a solenoid microcoil NMR difference probe is reported. STDD-NMR allows the investigation of ligand-biomolecule binding, with moderate concentration requirements for unlabeled molecular targets and the ability to discern binding events in the presence of non-binding ligands. The NMR difference probe acquires the signals from two different samples at once, and cancels common signals automatically through a mechanism of switching between parallel excitation and serial acquisition of the sample signals. STDD spectra were acquired on a system consisting of human serum albumin and two ligands, octanoic acid and glucose. The non-binding ligand, glucose, was cancelled internally through phase cycling, while the protein signal was subtracted automatically by the difference probe. The proton NMR resonance signal from octanoic acid remained in the double difference spectrum. This work demonstrates that the double difference can be performed both internally and automatically through the utilization of the solenoid microcoil NMR difference probe and STDD-NMR pulse sequence, resulting in a clean signal from the binding ligand with good protein background subtraction and an overall favorable result when compared to the conventional approach.
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Affiliation(s)
- Scott J. Bergeron
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Ian D. Henry
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Robert E. Santini
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Abdollah Aghdasi
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Daniel Raftery
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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16
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Abstract
The article brings a comprehensive survey of recent developments and applications of high-performance capillary electromigration methods, zone electrophoresis, ITP, IEF, affinity electrophoresis, EKC, and electrochromatography, to analysis, preparation, and physicochemical characterization of peptides. New approaches to the theoretical description and experimental verification of electromigration behavior of peptides and to methodology of their separations, such as sample preparation, adsorption suppression, and detection, are presented. Novel developments in individual CE and CEC modes are shown and several types of their applications to peptide analysis are presented: conventional qualitative and quantitative analysis, purity control, determination in biomatrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid and sequence analysis, and peptide mapping of proteins. Some examples of micropreparative peptide separations are given and capabilities of CE and CEC techniques to provide important physicochemical characteristics of peptides are demonstrated.
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Affiliation(s)
- Václav Kasicka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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17
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Wilson SR, Malerød H, Petersen D, Rise F, Lundanes E, Greibrokk T. An alternative multiple-trapping LC-SPE-NMR system. J Sep Sci 2007; 30:322-8. [PMID: 17396589 DOI: 10.1002/jssc.200600238] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this paper, we describe approaches that make RP LC-SPE-NMR simpler, and in our opinion, result in more reliable methods for trapping and subsequent transfer of separated trace-level compounds to the NMR. An SPE unit based on a commercially available, low dead-volume 10 port high-pressure column selector gives the possibility of trapping compounds on nine individual SPEs that have standard fittings. This allows the operator to employ specific stationary phases that are not available as SPEs in commercially available LC-SPE-NMR systems. Multiple trappings of small compounds like monuron, 1-(4-chlorophenyl)-3-methylurea, and 4-chlorophenylurea were easily performed employing a porous-carbon SPE material. The system was optimized to elute the SPE-trapped compounds to the NMR probes in as small a volume as possible using back-flushing. The proper match of NMR probe volume and SPE column inner diameter and elution volume was discussed, as well as the necessity of drying loaded SPEs prior to NMR transfer when using porous-carbon SPE material.
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Affiliation(s)
- Steven Ray Wilson
- Department of Chemistry, University of Oslo, Blindern, Oslo, Norway.
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18
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Schroeder FC, Gronquist M. Extending the scope of NMR spectroscopy with microcoil probes. Angew Chem Int Ed Engl 2007; 45:7122-31. [PMID: 16991159 DOI: 10.1002/anie.200601789] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Capillary NMR (CapNMR) spectroscopy has emerged as a major breakthrough for increasing the mass-sensitivity of NMR spectroscopic analysis and enabling the combination of NMR spectroscopy with other analytical techniques. Not only is the acquisition of high-sensitivity spectra getting easier but the quality of CapNMR spectra obtained in many small-molecule applications exceeds what can be accomplished with conventional designs. This Minireview discusses current CapNMR technology and its applications for the characterization of mass-limited, small-molecule and protein samples, the rapid screening of small-molecule or protein libraries, as well as hyphenated techniques that combine CapNMR with other analytical methods.
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Affiliation(s)
- Frank C Schroeder
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA.
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19
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Petr J, Maier V, Horáková J, Sevcík J, Stránský Z. Capillary isotachophoresis from the student point of view – images and the reality. J Sep Sci 2006; 29:2705-15. [PMID: 17305231 DOI: 10.1002/jssc.200600249] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A review of some fundamental aspects of ITP from the student point of view, imaginations of some basic facts and laws, use of ITP, and the recent trends are presented. The results of theoretical computations of ITP separation processes are added for comparison of imaginations with the exact mathematical description.
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Affiliation(s)
- Jan Petr
- Department of Analytical Chemistrý, Palackỳ University, Trída Svobody 8, Olomouc, Czech Republic.
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20
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Schroeder FC, Gronquist M. Größere Möglichkeiten für die NMR-Spektroskopie durch Mikrospulenprobenköpfe. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200601789] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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21
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Djukovic D, Liu S, Henry I, Tobias B, Raftery D. Signal enhancement in HPLC/microcoil NMR using automated column trapping. Anal Chem 2006; 78:7154-60. [PMID: 17037915 PMCID: PMC2577147 DOI: 10.1021/ac0605748] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A new HPLC NMR system is described that performs analytical separation, preconcentration, and NMR spectroscopy in rapid succession. The central component of our method is the online preconcentration sequence that improves the match between postcolumn analyte peak volume and microcoil NMR detection volume. Separated samples are collected on to a C18 guard column with a mobile phase composed of 90% D2O/10% acetonitrile-D3 and back-flushed to the NMR microcoil probe with 90% acetonitrile-D3/10% D2O. To assess the performance of our unit, we separated a standard mixture of 1 mM ibuprofen, naproxen, and phenylbutazone using a commercially available C18 analytical column. The S/N measurements from the NMR acquisitions indicated that we achieved signal enhancement factors up to 10.4 (+/-1.2)-fold. Furthermore, we observed that preconcentration factors increased as the injected amount of analyte decreased. The highest concentration enrichment of 14.7 (+/-2.2)-fold was attained injecting 100 microL of solution of 0.2 mM (approximately 4 microg) ibuprofen.
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Affiliation(s)
- Danijel Djukovic
- Department of Chemistry, Purdue University 560 Oval Drive, West Lafayette, IN 47907
| | - Shuhui Liu
- Department of Chemistry, Purdue University 560 Oval Drive, West Lafayette, IN 47907
| | - Ian Henry
- Department of Chemistry, Purdue University 560 Oval Drive, West Lafayette, IN 47907
| | | | - Daniel Raftery
- Department of Chemistry, Purdue University 560 Oval Drive, West Lafayette, IN 47907
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22
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The changing role of NMR spectroscopy in off-line impurity identification: A conceptual view. Trends Analyt Chem 2006. [DOI: 10.1016/j.trac.2006.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Wilson SR, Malerød H, Petersen D, Simic N, Bobu MM, Rise F, Lundanes E, Greibrokk T. Controlling LC–SPE–NMR systems. J Sep Sci 2006; 29:582-9. [PMID: 16583697 DOI: 10.1002/jssc.200500359] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
There are several stages of the LC-SPE-NMR process that should be monitored closely to ensure an efficient isolation and concentration of the target analyte, for instance analyte break-through and compound transfer from the LC-SPE to the NMR probe. In this study, analyte break-through monitoring was performed with a UV detector and a mass spectrometer placed after the SPE unit. Easy break-through was a problem when attempting multiple trapping of various compounds using C18 SPE cartridges with the original commercial system. However, on lowering the flow rate over the SPE system and using SPE cartridges packed with porous carbon, the number of trappings possible increased five-fold. To increase control over the on-line SPE-NMR transfer, a gradient pump-UV system was used to elute compounds trapped on an SPE to an NMR probe. The analyte band was placed in the active volume of the probe by a stop-flow mechanism. The modified LC-SPE system was also coupled with off-line NMR analysis for determination of a degradation product of the insecticide monuron, present in the low ppm range.
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