1
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Liang J, Davoodi H, Wadhwa S, Badilita V, Korvink JG. Broadband stripline Lenz lens achieves 11 × NMR signal enhancement. Sci Rep 2024; 14:1645. [PMID: 38238376 PMCID: PMC10796323 DOI: 10.1038/s41598-023-50616-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/22/2023] [Indexed: 01/22/2024] Open
Abstract
A Lenz lens is an electrically passive conductive element that, when placed in a time-varying magnetic field, acts as a magnetic flux concentrator or a magnetic lens. In the realm of nuclear magnetic resonance (NMR), Lenz lenses have been exploited as electrically passive metallic radiofrequency interposers placed between a sample and a tuned or untuned NMR detector in order to focus the [Formula: see text]-field of the detector onto a smaller sample space. Here we explore a novel embodiment of the Lenz lens, which acts as a non-resonant stripline interposer, i.e., the [Formula: see text]-field acts along the longitudinal volume of a sample container, such as a capillary or other microfluidic channel that is coincident with the axis of the stripline. The almost vanishing self-resonance of the stripline Lenz lens, at frequencies relevant for NMR, leads to a desirable [Formula: see text]-field amplitude that is nearly perfectly uniform across the sample and hence lacking a characteristic sinusoidal modal shape. The action of Lenz' law ensures that no stray [Formula: see text]-field is found outside of the stripline's active volume. Because the stripline Lenz lens does not rely on its own geometry to achieve resonance, its frequency response is thus widely broadband for field enhancements up to a factor of 11, with only the external driving resonator properties governing the overall resonant behaviour. We explore the use of the stripline Lenz lens with a sub-nanolitre sample volume, readily detecting 4 isotopes with resonances ranging from 125.76 to 500 MHz. The concept holds potential for the NMR study of thin films, small biological samples, as well as the in situ study of battery materials.
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Affiliation(s)
- Jianyi Liang
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany
| | | | | | - Vlad Badilita
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany.
| | - Jan G Korvink
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Germany.
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2
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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 PMCID: PMC10313780 DOI: 10.1038/s41467-023-39537-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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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3
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Jenne A, von der Ecken S, Moxley-Paquette V, Soong R, Swyer I, Bastawrous M, Busse F, Bermel W, Schmidig D, Kuehn T, Kuemmerle R, Al Adwan-Stojilkovic D, Graf S, Frei T, Monette M, Wheeler AR, Simpson AJ. Integrated Digital Microfluidics NMR Spectroscopy: A Key Step toward Automated In Vivo Metabolomics. Anal Chem 2023; 95:5858-5866. [PMID: 36996326 DOI: 10.1021/acs.analchem.2c04201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
Toxicity testing is currently undergoing a paradigm shift from examining apical end points such as death, to monitoring sub-lethal toxicity in vivo. In vivo nuclear magnetic resonance (NMR) spectroscopy is a key platform in this endeavor. A proof-of-principle study is presented which directly interfaces NMR with digital microfluidics (DMF). DMF is a "lab on a chip" method allowing for the movement, mixing, splitting, and dispensing of μL-sized droplets. The goal is for DMF to supply oxygenated water to keep the organisms alive while NMR detects metabolomic changes. Here, both vertical and horizontal NMR coil configurations are compared. While a horizontal configuration is ideal for DMF, NMR performance was found to be sub-par and instead, a vertical-optimized single-sided stripline showed most promise. In this configuration, three organisms were monitored in vivo using 1H-13C 2D NMR. Without support from DMF droplet exchange, the organisms quickly showed signs of anoxic stress; however, with droplet exchange, this was completely suppressed. The results demonstrate that DMF can be used to maintain living organisms and holds potential for automated exposures in future. However, due to numerous limitations of vertically orientated DMF, along with space limitations in standard bore NMR spectrometers, we recommend future development be performed using a horizontal (MRI style) magnet which would eliminate practically all the drawbacks identified here.
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Affiliation(s)
- Amy Jenne
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Sebastian von der Ecken
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Nicoya, B-29 King Street East, Kitchener, Ontario N2G 2K4, Canada
| | - Vincent Moxley-Paquette
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Ronald Soong
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Ian Swyer
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Monica Bastawrous
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - Falko Busse
- Bruker BioSpin GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany
| | - Daniel Schmidig
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Till Kuehn
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Rainer Kuemmerle
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | | | - Stephan Graf
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Thomas Frei
- Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Martine Monette
- Bruker Canada Ltd., 2800 High Point Drive, Milton, Ontario L9T 6P4, Canada
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute for Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - Andre J Simpson
- Department of Chemistry, University of Toronto, 80. St. George Street, Toronto, Ontario M5S 3H6, Canada
- Environmental NMR Center, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
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4
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Polishchuk D, Gardeniers H. A compact permanent magnet for microflow NMR relaxometry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 347:107364. [PMID: 36599254 DOI: 10.1016/j.jmr.2022.107364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
We design and demonstrate a compact, robust, and simple to assemble and tune permanent magnet suitable for NMR relaxometry measurements of microfluidic flows. Soft-magnetic stainless-steel plates, incorporated inside the magnet airgap, are key for obtaining substantially improved and tunable field homogeneity. The design is scalable for different NMR probe sizes with the region of suitable field homogeneity, less than 200 ppm, achievable in a capillary length of about 50 % of the total magnet length. The built physical prototype, having 3.5x3.5x8.0 cm3 in size and 5 mm high airgap, provides a field strength of 0.5 T and sufficient field homogeneity for NMR relaxometry measurements in capillaries up to 1.6 mm i.d. and 20 mm long. The magnet was used for test flow rate measurements in a wide range, from 0.001 ml/min to 20 ml/min.
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Affiliation(s)
- Dmytro Polishchuk
- Mesoscale Chemical Systems Group, University of Twente, 7500 AE Enschede, the Netherlands
| | - Han Gardeniers
- Mesoscale Chemical Systems Group, University of Twente, 7500 AE Enschede, the Netherlands.
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5
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Lepucki P, Dioguardi AP, Karnaushenko D, Schmidt OG, Grafe HJ. The normalized limit of detection in NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 332:107077. [PMID: 34634649 DOI: 10.1016/j.jmr.2021.107077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
We derive the normalized limit of detection for frequency space (nLODf) as a parameter to measure the sensitivity of an NMR spectroscopy setup. nLODf is independent of measurement settings such as bandwidth or number of measurement points, and allows to compare performances of different setups. We demonstrate the usefulness of the new nLODf by comparing the sensitivity of NMR setups from various publications, which all use microcoils. Finally, we want to propose a standard measurement and report format for the sensitivity of new NMR setups.
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Affiliation(s)
- Piotr Lepucki
- IFW Dresden, Institut für Festkörperforschung, Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Adam P Dioguardi
- IFW Dresden, Institut für Festkörperforschung, Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Daniil Karnaushenko
- IFW Dresden, Institut für Integrative Nanowissenschaften, Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Oliver G Schmidt
- IFW Dresden, Institut für Integrative Nanowissenschaften, Helmholtzstraße 20, 01069 Dresden, Germany; TU Dresden, Nanophysik, Häckelstraße 3, 01069 Dresden, Germany; TU Chemnitz, Material Systems for Nanoelectronics, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Hans-Joachim Grafe
- IFW Dresden, Institut für Festkörperforschung, Helmholtzstraße 20, 01069 Dresden, Germany.
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6
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Plata M, Hale W, Sharma M, Werner JM, Utz M. Microfluidic platform for serial mixing experiments with in operando nuclear magnetic resonance spectroscopy. LAB ON A CHIP 2021; 21:1598-1603. [PMID: 33662071 DOI: 10.1039/d0lc01100b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We present a microfluidic platform that allows in operando nuclear magnetic resonance (NMR) observation of serial mixing experiments. Gradually adding one reagent to another is a fundamental experimental modality, widely used to quantify equilibrium constants, for titrations, and in chemical kinetics studies. NMR provides a non-invasive means to quantify concentrations and to follow structural changes at the molecular level as a function of exchanged volume. Using active pneumatic valving on the microfluidic device directly inside an NMR spectrometer equipped with a transmission-line NMR microprobe, the system allows injection of aliquots and in situ mixing in a sample volume of less than 10 μL.
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Affiliation(s)
- Marek Plata
- School of Chemistry, University of Southampton, SO17 1BJ, UK. and Institute for Life Sciences, University of Southampton, SO17 1BJ, UK and School of Biological Sciences, University of Southampton, SO17 1BJ, UK
| | - William Hale
- School of Chemistry, University of Southampton, SO17 1BJ, UK.
| | | | - Jörn M Werner
- Institute for Life Sciences, University of Southampton, SO17 1BJ, UK and School of Biological Sciences, University of Southampton, SO17 1BJ, UK
| | - Marcel Utz
- School of Chemistry, University of Southampton, SO17 1BJ, UK. and Institute for Life Sciences, University of Southampton, SO17 1BJ, UK
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7
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Untuned broadband spiral micro-coils achieve sensitive multi-nuclear NMR TX/RX from microfluidic samples. Sci Rep 2021; 11:7798. [PMID: 33833324 PMCID: PMC8032710 DOI: 10.1038/s41598-021-87247-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/22/2021] [Indexed: 11/17/2022] Open
Abstract
The low frequency plateau in the frequency response of an untuned micro-resonator permits broadband radio-frequency reception, albeit at the expense of optimal signal-to-noise ratio for a particular nucleus. In this contribution we determine useful figures of merit for broadband micro-coils, and thereby explore the parametric design space towards acceptable simultaneous excitation and reception of a microfluidic sample over a wide frequency band ranging from 13C to 1H, i.e., 125–500 MHz in an 11.74 T magnet. The detector achieves 37% of the performance of a comparably sized, tuned and matched resonator, and a linewidth of 17 ppb using standard magnet shims. The use of broadband detectors circumvents numerous difficulties introduced by multi-resonant RF detector circuits, including sample loading effects on matching, channel isolation, and field distortion.
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8
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Time-resolved non-invasive metabolomic monitoring of a single cancer spheroid by microfluidic NMR. Sci Rep 2021; 11:53. [PMID: 33420162 PMCID: PMC7794408 DOI: 10.1038/s41598-020-79693-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/27/2020] [Indexed: 02/07/2023] Open
Abstract
We present a quantitative study of the metabolic activity of a single spheroid culture of human cancer cells. NMR (nuclear magnetic resonance) spectroscopy is an ideal tool for observation of live systems due to its non-invasive nature. However, limited sensitivity has so far hindered its application in microfluidic culture systems. We have used an optimised micro-NMR platform to observe metabolic changes from a single spheroid. NMR spectra were obtained by directly inserting microfluidic devices containing spheroids ranging from 150 [Formula: see text]m to 300 [Formula: see text]m in diameter in 2.5 [Formula: see text]L of culture medium into a dedicated NMR probe. Metabolite concentrations were found to change linearly with time, with rates approximately proportional to the number of cells in the spheroid. The results demonstrate that quantitative monitoring of a single spheroid with [Formula: see text] 2500 cells is possible. A change in spheroid size by 600 cells leads to a clearly detectable change in the L-Lactic acid production rate ([Formula: see text]). The consumption of D-Glucose and production of L-Lactic acid were approximately 2.5 times slower in spheroids compared to monolayer culture of the same number of cells. Moreover, while cells in monolayer culture were found to produce L-Alanine and L-Glutamine, spheroids showed slight consumption in both cases.
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9
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Korvink JG, MacKinnon N, Badilita V, Jouda M. "Small is beautiful" in NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 306:112-117. [PMID: 31337561 DOI: 10.1016/j.jmr.2019.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/31/2019] [Accepted: 07/08/2019] [Indexed: 05/03/2023]
Abstract
In this prospective paper we consider the opportunities and challenges of miniaturized nuclear magnetic resonance. As the title suggests, (irreverently borrowing from E.F. Schumacher's famous book), miniaturized NMR will feature a few small windows of opportunity for the analyst. We look at what these are, speculate on some open opportunities, but also comment on the challenges to progress.
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Affiliation(s)
- Jan G Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Neil MacKinnon
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Vlad Badilita
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Mazin Jouda
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
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10
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Davoodi H, Jouda M, Korvink JG, MacKinnon N, Badilita V. Broadband and multi-resonant sensors for NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:34-54. [PMID: 31481158 DOI: 10.1016/j.pnmrs.2019.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 06/10/2023]
Abstract
It has always been of considerable interest to study the nuclear magnetic resonance response of multiple nuclei simultaneously, whether these signals arise from internuclear couplings within the same molecule, or from uncoupled nuclei within sample mixtures. The literature contains numerous uncorrelated reports on techniques employed to achieve multi-nuclear NMR detection. This paper consolidates the subset of techniques in which single coil detectors are utilized, and highlights the strengths and weaknesses of each approach, at the same time pointing the way towards future developments in the field of multi-nuclear NMR. We compare the different multi-nuclear NMR techniques in terms of performance, and present a guide to NMR probe designers towards application-based optimum design. We also review the applicability of micro-coils in the context of multi-nuclear methods. Micro-coils benefit from compact geometries and exhibit lower impedance, which provide new opportunities and challenges for the NMR probe designer.
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Affiliation(s)
- Hossein Davoodi
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Baden-Württemberg, Germany
| | - Mazin Jouda
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Baden-Württemberg, Germany
| | - Jan G Korvink
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Baden-Württemberg, Germany.
| | - Neil MacKinnon
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Baden-Württemberg, Germany
| | - Vlad Badilita
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Baden-Württemberg, Germany.
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11
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Eills J, Hale W, Sharma M, Rossetto M, Levitt MH, Utz M. High-Resolution Nuclear Magnetic Resonance Spectroscopy with Picomole Sensitivity by Hyperpolarization on a Chip. J Am Chem Soc 2019; 141:9955-9963. [DOI: 10.1021/jacs.9b03507] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- James Eills
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, United Kingdom
| | - William Hale
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, United Kingdom
| | - Manvendra Sharma
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, United Kingdom
| | - Matheus Rossetto
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, United Kingdom
| | - Malcolm H. Levitt
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, United Kingdom
| | - Marcel Utz
- School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1BJ, United Kingdom
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12
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Oosthoek-de Vries AJ, Nieuwland PJ, Bart J, Koch K, Janssen JWG, van Bentum PJM, Rutjes FPJT, Gardeniers HJGE, Kentgens APM. Inline Reaction Monitoring of Amine-Catalyzed Acetylation of Benzyl Alcohol Using a Microfluidic Stripline Nuclear Magnetic Resonance Setup. J Am Chem Soc 2019; 141:5369-5380. [PMID: 30864795 PMCID: PMC6449804 DOI: 10.1021/jacs.9b00039] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Indexed: 12/30/2022]
Abstract
We present an in-depth study of the acetylation of benzyl alcohol in the presence of N, N-diisopropylethylamine (DIPEA) by nuclear magnetic resonance (NMR) monitoring of the reaction from 1.5 s to several minutes. We have adapted the NMR setup to be compatible to microreactor technology, scaling down the typical sample volume of commercial NMR probes (500 μL) to a microfluidic stripline setup with 150 nL detection volume. Inline spectra are obtained to monitor the kinetics and unravel the reaction mechanism of this industrially relevant reaction. The experiments are combined with conventional 2D NMR measurements to identify the reaction products. In addition, we replace DIPEA with triethylamine and pyridine to validate the reaction mechanism for different amine catalysts. In all three acetylation reactions, we find that the acetyl ammonium ion is a key intermediate. The formation of ketene is observed during the first minutes of the reaction when tertiary amines were present. The pyridine-catalyzed reaction proceeds via a different mechanism.
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Affiliation(s)
| | - Pieter J. Nieuwland
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
- FutureChemistry
Holding B.V., Nijmegen, The Netherlands
| | - Jacob Bart
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
| | - Kaspar Koch
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
- FutureChemistry
Holding B.V., Nijmegen, The Netherlands
| | - Johannes W. G. Janssen
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
| | - P. Jan M. van Bentum
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
| | - Floris P. J. T. Rutjes
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
| | | | - Arno P. M. Kentgens
- Institute
of Molecules and Materials, Radboud University
Nijmegen, Nijmegen, The Netherlands
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13
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Swyer I, von der Ecken S, Wu B, Jenne A, Soong R, Vincent F, Schmidig D, Frei T, Busse F, Stronks HJ, Simpson AJ, Wheeler AR. Digital microfluidics and nuclear magnetic resonance spectroscopy for in situ diffusion measurements and reaction monitoring. LAB ON A CHIP 2019; 19:641-653. [PMID: 30648175 DOI: 10.1039/c8lc01214h] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In recent years microcoils and related structures have been developed to increase the mass sensitivity of nuclear magnetic resonance spectroscopy, allowing this extremely powerful analytical technique to be extended to small sample volumes (<5 μl). In general, microchannels have been used to deliver the samples of interest to these microcoils; however, these systems tend to have large dead volumes and require more complex fluidic connections. Here, we introduce a two-plate digital microfluidic (DMF) strategy to interface small-volume samples with NMR microcoils. In this system, a planar microcoil is surrounded by a copper plane that serves as the counter-electrode for the digital microfluidic device, allowing for precise control of droplet position and shape. This feature allows for the user-determination of the orientation of droplets relative to the main axes of the shim stack, permitting improved shimming and a more homogeneous magnetic field inside the droplet below the microcoil, which leads to improved spectral lineshape. This, along with high-fidelity droplet actuation, allows for rapid shimming strategies (developed over decades for vertically oriented NMR tubes) to be employed, permitting the determination of reaction-product diffusion coefficients as well as quantitative monitoring of reactive intermediates. We propose that this system paves the way for new and exciting applications for in situ analysis of small samples by NMR spectroscopy.
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Affiliation(s)
- Ian Swyer
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6, Canada.
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14
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Kamberger R, Göbel-Guéniot K, Gerlach J, Gruschke OG, Hennig J, LeVan P, Haas C, Korvink JG. Improved method for MR microscopy of brain tissue cultured with the interface method combined with Lenz lenses. Magn Reson Imaging 2018; 52:24-32. [PMID: 29857037 DOI: 10.1016/j.mri.2018.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 05/21/2018] [Accepted: 05/21/2018] [Indexed: 12/17/2022]
Abstract
MR in microscopy can non-invasively image the morphology of living tissue, which is of particular interest in studying the mammalian brain. Many studies use live animals for basic research on brain functions, disease pathogenesis, and drug development. However, in vitro systems are on the rise, due to advantages such as the absence of a blood-brain barrier, predictable pharmacokinetics, and reduced ethical restrictions. Hence, they present an inexpensive and adequate technique to answer scientific questions and to perform drug screenings. Some publications report the use of acute brain slices for MR microscopy studies, but these only permit single measurements over several hours. Repetitive MR measurements in longitudinal studies demand an MR-compatible setup which allows cultivation for several days or weeks, and hence properly functioning in vitro systems. Organotypic hippocampal slice cultures (OHSC) are a well-established and robust in vitro system which still exhibits most histological hallmarks of the hippocampal network in vivo. An MR compatible incubation platform is introduced in which OHSC are cultivated according to the interface method following Stoppini et al. In this cultivation method a tissue slice is placed onto a membrane with nutrition medium underneath and a gas atmosphere above, where the air-tissue interface perpendicular to the B0 field induces strong artefacts. We introduce a handling protocol that suppresses these artefacts and increases signal quality significantly to acquire high resolution images of tissue slices. An additional challenge is the lack of available of MR microscopy equipment suitable for small animal scanners. A Lenz lens with an attached capacitor can dramatically increase the SNR in these cases, and wirelessly bring the detection system in close proximity to the sample without compromising the OHSC system through the introduction of wired detectors. The resultant signal gain is demonstrated by imaging a PFA-fixed brain slice with a 72 mm diameter volume coil without a Lenz lens, and with a broadband and a self-resonant Lenz lens. In our setting, the self-resonant Lenz lens increases the SNR 10-fold over using the volume coil only.
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Affiliation(s)
- R Kamberger
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany
| | - K Göbel-Guéniot
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Medical Physics, Department of Radiology, Medical Center - University of Freiburg, Germany
| | - J Gerlach
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Experimental Epilepsy Laboratory, Department of Neurosurgery, Medical Center - University of Freiburg, Germany
| | - O G Gruschke
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Germany
| | - J Hennig
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Medical Physics, Department of Radiology, Medical Center - University of Freiburg, Germany
| | - P LeVan
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Medical Physics, Department of Radiology, Medical Center - University of Freiburg, Germany
| | - C Haas
- BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany; Experimental Epilepsy Laboratory, Department of Neurosurgery, Medical Center - University of Freiburg, Germany
| | - J G Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Germany.
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15
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Chen Y, Mehta HS, Butler MC, Walter ED, Reardon PN, Renslow RS, Mueller KT, Washton NM. High-resolution microstrip NMR detectors for subnanoliter samples. Phys Chem Chem Phys 2018; 19:28163-28174. [PMID: 29022609 DOI: 10.1039/c7cp03933f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We present the numerical optimization and experimental characterization of two microstrip-based nuclear magnetic resonance (NMR) detectors. The first detector, introduced in our previous work, was a flat wire detector with a strip resting on a substrate, and the second detector was created by adding a ground plane on top of the strip conductor, separated by a sample-carrying capillary and a thin layer of insulator. The dimensional parameters of the detectors were optimized using numerical simulations with regards to radio frequency (RF) sensitivity and homogeneity, with particular attention given to the effect of the ground plane. The influence of copper surface finish and substrate surface on the spectral resolution was investigated, and a resolution of 0.8-1.5 Hz was obtained on 1 nL deionized water depending on sample positioning. For 0.13 nmol sucrose (0.2 M in 0.63 nL H2O) encapsulated between two Fluorinert plugs, high RF homogeneity (A810°/A90° = 70-80%) and high sensitivity (expressed in the limit of detection nLODm = 0.73-1.21 nmol s1/2) were achieved, allowing for high-performance 2D NMR spectroscopy of subnanoliter samples.
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Affiliation(s)
- Ying Chen
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
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16
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Meier T, Wang N, Mager D, Korvink JG, Petitgirard S, Dubrovinsky L. Magnetic flux tailoring through Lenz lenses for ultrasmall samples: A new pathway to high-pressure nuclear magnetic resonance. SCIENCE ADVANCES 2017; 3:eaao5242. [PMID: 29230436 PMCID: PMC5724354 DOI: 10.1126/sciadv.aao5242] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 11/09/2017] [Indexed: 05/31/2023]
Abstract
A new pathway to nuclear magnetic resonance (NMR) spectroscopy for picoliter-sized samples (including those kept in harsh and extreme environments, particularly in diamond anvil cells) is introduced, using inductively coupled broadband passive electromagnetic lenses, to locally amplify the magnetic field at the isolated sample, leading to an increase in sensitivity. The lenses are adopted for the geometrical restrictions imposed by a toroidal diamond indenter cell and yield signal-to-noise ratios at pressures as high as 72 GPa at initial sample volumes of only 230 pl. The corresponding levels of detection are found to be up to four orders of magnitude lower compared to formerly used solenoidal microcoils. Two-dimensional nutation experiments on long-chained alkanes, CnH2n+2 (n = 16 to 24), as well as homonuclear correlation spectroscopy on thymine, C5H6N2O2, were used to demonstrate the feasibility of this approach for higher-dimensional NMR experiments, with a spectral resolution of at least 2 parts per million. This approach opens up the field of ultrahigh-pressure sciences to one of the most versatile spectroscopic methods available in a pressure range unprecedented up to now.
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Affiliation(s)
- Thomas Meier
- Bayerisches Geoinstitut, Bayreuth University, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Nan Wang
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Dario Mager
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Jan G. Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Sylvain Petitgirard
- Bayerisches Geoinstitut, Bayreuth University, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Leonid Dubrovinsky
- Bayerisches Geoinstitut, Bayreuth University, Universitätsstraße 30, 95447 Bayreuth, Germany
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17
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Jouda M, Kamberger R, Leupold J, Spengler N, Hennig J, Gruschke O, Korvink JG. A comparison of Lenz lenses and LC resonators for NMR signal enhancement. CONCEPTS IN MAGNETIC RESONANCE. PART B, MAGNETIC RESONANCE ENGINEERING 2017; 47B:e21357. [PMID: 29541005 PMCID: PMC5839471 DOI: 10.1002/cmr.b.21357] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/11/2017] [Accepted: 10/26/2017] [Indexed: 06/09/2023]
Abstract
High signal-to-noise ratio (SNR) of the NMR signal has always been a key target that drives massive research effort in many fields. Among several parameters, a high filling factor of the MR coil has proven to boost the SNR. In case of small-volume samples, a high filling factor and thus a high SNR can be achieved through miniaturizing the MR coil. However, under certain circumstances, this can be impractical. In this paper, we present an extensive theoretical and experimental investigation of the inductively coupled LC resonator and the magnetic Lenz lens as two candidate approaches that can enhance the SNR in such circumstances. The results demonstrate that the narrow-band LC resonator is superior in terms of SNR, while the non-tuned nature of the Lenz lens makes it preferable in broadband applications.
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Affiliation(s)
- Mazin Jouda
- Karlsruhe Institute of Technology‐KITInstitute of Microstructure Technology‐IMTEggenstein‐LeopoldshafenGermany
| | - Robert Kamberger
- BrainLinks‐BrainTools Cluster of ExcellenceInstitute of Microsystems Technology‐IMTEKUniversity of FreiburgFreiburgGermany
| | - Jochen Leupold
- Department of RadiologyMedical PhysicsMedical Center ‐ University of FreiburgFaculty of MedicineUniversity of FreiburgFreiburgGermany
| | | | - Jürgen Hennig
- Department of RadiologyMedical PhysicsMedical Center ‐ University of FreiburgFaculty of MedicineUniversity of FreiburgFreiburgGermany
| | | | - Jan G. Korvink
- Karlsruhe Institute of Technology‐KITInstitute of Microstructure Technology‐IMTEggenstein‐LeopoldshafenGermany
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18
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Oosthoek-de Vries AJ, Bart J, Tiggelaar RM, Janssen JWG, van Bentum PJM, Gardeniers HJGE, Kentgens APM. Continuous Flow 1H and 13C NMR Spectroscopy in Microfluidic Stripline NMR Chips. Anal Chem 2017; 89:2296-2303. [PMID: 28194934 PMCID: PMC5337998 DOI: 10.1021/acs.analchem.6b03784] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 01/23/2017] [Indexed: 12/28/2022]
Abstract
Microfluidic stripline NMR technology not only allows for NMR experiments to be performed on small sample volumes in the submicroliter range, but also experiments can easily be performed in continuous flow because of the stripline's favorable geometry. In this study we demonstrate the possibility of dual-channel operation of a microfluidic stripline NMR setup showing one- and two-dimensional 1H, 13C and heteronuclear NMR experiments under continuous flow. We performed experiments on ethyl crotonate and menthol, using three different types of NMR chips aiming for straightforward microfluidic connectivity. The detection volumes are approximately 150 and 250 nL, while flow rates ranging from 0.5 μL/min to 15 μL/min have been employed. We show that in continuous flow the pulse delay is determined by the replenishment time of the detector volume, if the sample trajectory in the magnet toward NMR detector is long enough to polarize the spin systems. This can considerably speed up quantitative measurement of samples needing signal averaging. So it can be beneficial to perform continuous flow measurements in this setup for analysis of, e.g., reactive, unstable, or mass-limited compounds.
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Affiliation(s)
| | - Jacob Bart
- Institute
of Molecules and Materials, Radboud University, 6525 HP Nijmegen, The Netherlands
- Mesoscale
Chemical Systems, MESA+ Institute of Nanotechnology, University of Twente, 7522
NB Enschede, The Netherlands
| | - Roald M. Tiggelaar
- Mesoscale
Chemical Systems, MESA+ Institute of Nanotechnology, University of Twente, 7522
NB Enschede, The Netherlands
| | - Johannes W. G. Janssen
- Institute
of Molecules and Materials, Radboud University, 6525 HP Nijmegen, The Netherlands
| | - P. Jan M. van Bentum
- Institute
of Molecules and Materials, Radboud University, 6525 HP Nijmegen, The Netherlands
| | - Han J. G. E. Gardeniers
- Mesoscale
Chemical Systems, MESA+ Institute of Nanotechnology, University of Twente, 7522
NB Enschede, The Netherlands
| | - Arno P. M. Kentgens
- Institute
of Molecules and Materials, Radboud University, 6525 HP Nijmegen, The Netherlands
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19
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Renslow RS, Marshall MJ, Tucker AE, Chrisler WB, Yu XY. In situ nuclear magnetic resonance microimaging of live biofilms in a microchannel. Analyst 2017; 142:2363-2371. [DOI: 10.1039/c7an00078b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The firstin situnuclear magnetic resonance microimaging of live biofilms in a transferrable microfluidic platform.
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Affiliation(s)
- R. S. Renslow
- Earth and Biological Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
| | - M. J. Marshall
- Earth and Biological Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
| | - A. E. Tucker
- Earth and Biological Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
| | - W. B. Chrisler
- Earth and Biological Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
| | - X.-Y. Yu
- Earth and Biological Sciences Directorate
- Pacific Northwest National Laboratory
- Richland
- USA
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20
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In vivo online magnetic resonance quantification of absolute metabolite concentrations in microdialysate. Sci Rep 2016; 6:36080. [PMID: 27811972 PMCID: PMC5095764 DOI: 10.1038/srep36080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 10/11/2016] [Indexed: 12/23/2022] Open
Abstract
In order to study metabolic processes in animal models of diseases and in patients, microdialysis probes have evolved as powerful tools that are minimally invasive. However, analyses of microdialysate, performed remotely, do not provide real-time monitoring of microdialysate composition. Microdialysate solutions can theoretically be analyzed online inside a preclicinal or clinical MRI scanner using MRS techniques. Due to low NMR sensitivity, acquisitions of real-time NMR spectra on very small solution volumes (μL) with low metabolite concentrations (mM range) represent a major issue. To address this challenge we introduce the approach of combining a microdialysis probe with a custom-built magnetic resonance microprobe that allows for online metabolic analysis (1H and 13C) with high sensitivity under continuous flow conditions. This system is mounted inside an MRI scanner and allows performing simultaneously MRI experiments and rapid MRS metabolic analysis of the microdialysate. The feasibility of this approach is demonstrated by analyzing extracellular brain cancer cells (glioma) in vitro and brain metabolites in an animal model in vivo. We expect that our approach is readily translatable into clinical settings and can be used for a better and precise understanding of diseases linked to metabolic dysfunction.
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21
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Swyer I, Soong R, Dryden MDM, Fey M, Maas WE, Simpson A, Wheeler AR. Interfacing digital microfluidics with high-field nuclear magnetic resonance spectroscopy. LAB ON A CHIP 2016; 16:4424-4435. [PMID: 27757467 DOI: 10.1039/c6lc01073c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is extremely powerful for chemical analysis but it suffers from lower mass sensitivity compared to many other analytical detection methods. NMR microcoils have been developed in response to this limitation, but interfacing these coils with small sample volumes is a challenge. We introduce here the first digital microfluidic system capable of interfacing droplets of analyte with microcoils in a high-field NMR spectrometer. A finite element simulation was performed to assist in determining appropriate system parameters. After optimization, droplets inside the spectrometer could be controlled remotely, permitting the observation of processes such as xylose-borate complexation and glucose oxidase catalysis. We propose that the combination of DMF and NMR will be a useful new tool for a wide range of applications in chemical analysis.
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Affiliation(s)
- Ian Swyer
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON M5S 3H6, Canada.
| | - Ronald Soong
- Department of Chemistry, University of Toronto Scarborough, 1256 Military Trail, Toronto, ON M1C 1A4, Canada.
| | - Michael D M Dryden
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON M5S 3H6, Canada.
| | - Michael Fey
- Bruker BioSpin Corp, 15 Fortune Drive, Billerica, Massachusetts 01821-3991, USA
| | - Werner E Maas
- Bruker BioSpin Corp, 15 Fortune Drive, Billerica, Massachusetts 01821-3991, USA
| | - André Simpson
- Department of Chemistry, University of Toronto Scarborough, 1256 Military Trail, Toronto, ON M1C 1A4, Canada.
| | - Aaron R Wheeler
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON M5S 3H6, Canada. and Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St, Toronto, ON M5S 3E1, Canada and Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5S 3G9, Canada
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22
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Yilmaz A, Utz M. Characterisation of oxygen permeation into a microfluidic device for cell culture by in situ NMR spectroscopy. LAB ON A CHIP 2016; 16:2079-2085. [PMID: 27149932 DOI: 10.1039/c6lc00396f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A compact microfluidic device for perfusion culture of mammalian cells under in situ metabolomic observation by NMR spectroscopy is presented. The chip is made from poly(methyl methacrylate) (PMMA), and uses a poly(dimethyl siloxane) (PDMS) membrane to allow gas exchange. It is integrated with a generic micro-NMR detector developed recently by our group [J. Magn. Reson., 2016, 262, 73-80]. While PMMA is an excellent material in the context of NMR, PDMS is known to produce strong background signals. To mitigate this, the device keeps the PDMS away from the detection area. The oxygen permeation into the device is quantified using a flow chemistry approach. A solution of glucose is mixed on the chip with a solution of glucose oxidase, before flowing through the gas exchanger. The resulting concentration of gluconate is measured by (1)H NMR spectroscopy as a function of flow rate. An oxygen equilibration rate constant of 2.4 s(-1) is found for the device, which is easily sufficient to maintain normoxic conditions in a cell culture at low perfusion flow rates.
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Affiliation(s)
- Ali Yilmaz
- School of Chemistry, University of Southampton, SO17 1BJ, UK.
| | - Marcel Utz
- School of Chemistry, University of Southampton, SO17 1BJ, UK.
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23
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Anders J, Handwerker J, Ortmanns M, Boero G. A low-power high-sensitivity single-chip receiver for NMR microscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 266:41-50. [PMID: 27011023 DOI: 10.1016/j.jmr.2016.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 06/05/2023]
Abstract
In this paper, we present a fully-integrated receiver for NMR microscopy applications manufactured in a 0.13μm CMOS technology. The design co-integrates a 10-turn planar detection coil together with a complete quadrature, low-IF downconversion receiver on a single chip, which operates from a single 1.5V supply with a total power dissipation of 18mW. The detector's measured time-domain spin sensitivity is 3×10(13)(1)Hspins/Hz at 7T. Additionally, the paper discusses two important aspects of NMR microscopy using planar detection coils: the link between the detection coil's spin sensitivity and the achievable image SNR and the correction of image artifacts induced by the inhomogeneous sensitivity profile of planar detection coils. More specifically, we derive analytical expressions for both the theoretical image SNR as a function of the coil's spin sensitivity and the sensitivity correction for a known coil sensitivity profile in CTI MR imaging experiments. Both expressions are validated using measured data in the imaging section of the paper. Thanks to the improved spin sensitivity of the utilized integrated receiver chip compared to a previously presented design, we were able to obtain sensitivity corrected images in a 7T spectroscopy magnet with isotropic resolutions of 9.6μm and 5μm with single-shot SNRs of 37 and 15 in relatively short imaging times of 4.4h and 24h, respectively.
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Affiliation(s)
- Jens Anders
- University of Ulm, Institute of Microelectronics, Albert-Einstein-Allee 43, D-89081 Ulm, Germany; Ecole Polytechnique Federale de Lausanne (EPFL), Institute of Microengineering, Station 17, CH-1015 Lausanne, Switzerland.
| | - Jonas Handwerker
- University of Ulm, Institute of Microelectronics, Albert-Einstein-Allee 43, D-89081 Ulm, Germany
| | - Maurits Ortmanns
- University of Ulm, Institute of Microelectronics, Albert-Einstein-Allee 43, D-89081 Ulm, Germany
| | - Giovanni Boero
- Ecole Polytechnique Federale de Lausanne (EPFL), Institute of Microengineering, Station 17, CH-1015 Lausanne, Switzerland
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24
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Finch G, Yilmaz A, Utz M. An optimised detector for in-situ high-resolution NMR in microfluidic devices. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 262:73-80. [PMID: 26754062 DOI: 10.1016/j.jmr.2015.11.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 06/05/2023]
Abstract
Integration of high-resolution nuclear magnetic resonance (NMR) spectroscopy with microfluidic lab-on-a-chip devices is challenging due to limited sensitivity and line broadening caused by magnetic susceptibility inhomogeneities. We present a novel double-stripline NMR probe head that accommodates planar microfluidic devices, and obtains the NMR spectrum from a rectangular sample chamber on the chip with a volume of 2μl. Finite element analysis was used to jointly optimise the detector and sample volume geometry for sensitivity and RF homogeneity. A prototype of the optimised design has been built, and its properties have been characterised experimentally. The performance in terms of sensitivity and RF homogeneity closely agrees with the numerical predictions. The system reaches a mass limit of detection of 1.57nmols, comparing very favourably with other micro-NMR systems. The spectral resolution of this chip/probe system is better than 1.75Hz at a magnetic field of 7T, with excellent line shape.
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Affiliation(s)
- Graeme Finch
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Ali Yilmaz
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Marcel Utz
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
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25
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Kind J, Thiele CM. Still shimming or already measuring?--Quantitative reaction monitoring for small molecules on the sub minute timescale by NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:109-115. [PMID: 26433632 DOI: 10.1016/j.jmr.2015.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/11/2015] [Accepted: 09/13/2015] [Indexed: 06/05/2023]
Abstract
In order to enable monitoring of rapidly occurring reactions Wagner et al. recently presented a simple scheme for 1D NMR experiments with continuous data acquisition, without inter-scan delays, using a spatially-selective and frequency-shifted excitation approach (Wagner et al., 2013). This scheme allows acquisition of proton spectra with temporal resolutions on the millisecond timescale. Such high temporal resolutions are desired in the case of reaction monitoring using stopped flow setups. In regular (1)H NMR-spectra without spatial selection the line width increases for a given shim setting with changes in sample volume, susceptibility, convection and temperature or concentration gradients due to the disturbance of magnetic field homogeneity. Concerning reaction monitoring this is unfortunate as shimming prior to acquisition becomes necessary to obtain narrow signals after injection of a reactant into an NMR sample. Even automatic shim routines may last up to minutes. Thus fast reactions can hardly be monitored online without large hardware dead times in a single stopped flow experiment. This problem is reduced in the spatially-selective and frequency-shifted continuous NMR experiment as magnetic field inhomogeneties are less pronounced and negative effects on the obtained line shapes are reduced as pointed out by Bax and Freeman (1980) [2] and demonstrated by Wagner et al. (2013). Here we present the utilization of this technique for observation of reactions in small molecule systems in which chemical conversion and longitudinal relaxation occur on the same timescale. By means of the alkaline ethyl acetate hydrolysis, a stoichiometric reaction, we show advantages of spatially-selective excitation on both temporal resolution and line shapes in stopped flow experiments. Results are compared to data obtained by non-selective small angle excitation experiments.
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Affiliation(s)
- J Kind
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 16, D-64287 Darmstadt, Germany
| | - C M Thiele
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 16, D-64287 Darmstadt, Germany.
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26
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Ryan H, Smith A, Utz M. Structural shimming for high-resolution nuclear magnetic resonance spectroscopy in lab-on-a-chip devices. LAB ON A CHIP 2014; 14:1678-1685. [PMID: 24658666 DOI: 10.1039/c3lc51431e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
High-resolution proton NMR spectroscopy is well-established as a tool for metabolomic analysis of biological fluids at the macro scale. Its full potential has, however, not been realised yet in the context of microfluidic devices. While microfabricated NMR detectors offer substantial gains in sensitivity, limited spectral resolution resulting from mismatches in the magnetic susceptibility of the sample fluid and the chip material remains a major hurdle. In this contribution, we show that susceptibility broadening can be avoided even in the presence of substantial mismatch by including suitably shaped compensation structures into the chip design. An efficient algorithm for the calculation of field maps from arbitrary chip layouts based on Gaussian quadrature is used to optimise the shape of the compensation structure to ensure a flat field distribution inside the sample area. Previously, the complexity of microfluidic NMR systems has been restricted to simple capillaries to avoid susceptibility broadening. The structural shimming approach introduced here can be adapted to virtually any shape of sample chamber and surrounding fluidic network, thereby greatly expanding the design space and enabling true lab-on-a-chip systems suitable for high-resolution NMR detection.
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Affiliation(s)
- Herbert Ryan
- School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
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27
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Zalesskiy SS, Danieli E, Blümich B, Ananikov VP. Miniaturization of NMR systems: desktop spectrometers, microcoil spectroscopy, and "NMR on a chip" for chemistry, biochemistry, and industry. Chem Rev 2014; 114:5641-94. [PMID: 24779750 DOI: 10.1021/cr400063g] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sergey S Zalesskiy
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Moscow, 119991, Russia
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28
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Chiwan Koo, Godley RF, McDougall MP, Wright SM, Han A. A microfluidically cryocooled spiral microcoil with inductive coupling for MR microscopy. IEEE Trans Biomed Eng 2014; 61:76-84. [PMID: 23955689 DOI: 10.1109/tbme.2013.2276770] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Magnetic resonance (MR) microscopy typically employs microcoils for enhanced local signal-to-noise ratio (SNR). Planar (surface) microcoils, in particular, offer the potential to be configured into array elements as well as to enable the imaging of extremely small samples because of the uniformity and precision provided by microfabrication techniques. Microcoils, in general, however, are copper-loss dominant, and cryocooling methods have been successfully used to improve the SNR. Cryocooling of the matching network elements, in addition to the coil itself, has shown to provide the most improvement, but can be challenging with respect to cryostat requirements, cabling, and tuning. Here we present the development of a microfluidically cryocooled spiral microcoil with integrated microfabricated parallel plate capacitors, allowing for localized cryocooling of both the microcoil and the on-chip resonating capacitor to increase the SNR while keeping the sample-to-coil distance within the most sensitive imaging range of the microcoil. Inductive coupling was used instead of a direct transmission line connection to eliminate the physical connection between the microcoil and the tuning network so that a single cryocooling microfluidic channel could enclose both the microcoil and the on-chip capacitor with minimum loss in cooling capacity. Comparisons between the cooled and uncooled cases were made via Q-factor measurements and agreed well with the theoretically achievable improvement: the cooled integrated capacitor coil with inductive coupling achieved a factor of 2.6 improvement in Q-factor over a reference coil conventionally matched and tuned with high- Q varactors and capacitively connected to the transmission line.
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Kašička V. Recent developments in capillary and microchip electroseparations of peptides (2011-2013). Electrophoresis 2013; 35:69-95. [PMID: 24255019 DOI: 10.1002/elps.201300331] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/10/2013] [Accepted: 09/10/2013] [Indexed: 01/15/2023]
Abstract
The review presents a comprehensive survey of recent developments and applications of capillary and microchip electroseparation methods (zone electrophoresis, ITP, IEF, affinity electrophoresis, EKC, and electrochromatography) for analysis, isolation, purification, and physicochemical and biochemical characterization of peptides. Advances in the investigation of electromigration properties of peptides, in the methodology of their analysis, including sample preseparation, preconcentration and derivatization, adsorption suppression and EOF control, as well as in detection of peptides, are presented. New developments in particular CE and CEC modes are reported and several types of their applications to peptide analysis are described: conventional qualitative and quantitative analysis, determination in complex (bio)matrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid, sequence and chiral analysis, and peptide mapping of proteins. Some micropreparative peptide separations are shown and capabilities of CE and CEC techniques to provide relevant physicochemical characteristics of peptides are demonstrated.
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Affiliation(s)
- Václav Kašička
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Zhivonitko VV, Telkki VV, Leppäniemi J, Scotti G, Franssila S, Koptyug IV. Remote detection NMR imaging of gas phase hydrogenation in microfluidic chips. LAB ON A CHIP 2013; 13:1554-1561. [PMID: 23435499 DOI: 10.1039/c3lc41309h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The heterogeneous hydrogenation reaction of propene into propane in microreactors is studied by remote detection (RD) nuclear magnetic resonance (NMR). The reactors consist of 36 parallel microchannels (50 × 50 μm(2) cross sections) coated with a platinum catalyst. We show that RD NMR is capable of monitoring reactions with sub-millimeter spatial resolution over a field-of-view of 30 × 8 mm(2) with a steady-state time-of-flight time resolution in the tens of milliseconds range. The method enables the visualization of active zones in the reactors, and time-of-flight is used to image the flow velocity variations inside the reactor. The overall reaction yields determined by NMR varied from 10% to 50%, depending on the flow rate, temperature and length of the reaction channels. The reaction yield was highest for the channels with the lowest flow velocity. Propane T1 relaxation time in the channels, estimated by means of RD NMR images, was 270 ± 18 ms. No parahydrogen-induced polarization (PHIP) was observed in experiments carried out using parahydrogen-enriched H2, indicating fast spreading of the hydrogen atoms on the sputtered Pt surface. In spite of the low concentration of gases, RD NMR made imaging of gas phase hydrogenation of propene in microreactors feasible, and it is a highly versatile method for characterizing on-chip chemical reactions.
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Affiliation(s)
- Vladimir V Zhivonitko
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk 630090, Russia.
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Kovarik ML, Ornoff DM, Melvin AT, Dobes NC, Wang Y, Dickinson AJ, Gach PC, Shah PK, Allbritton NL. Micro total analysis systems: fundamental advances and applications in the laboratory, clinic, and field. Anal Chem 2013; 85:451-72. [PMID: 23140554 PMCID: PMC3546124 DOI: 10.1021/ac3031543] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Michelle L. Kovarik
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Douglas M. Ornoff
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Adam T. Melvin
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Nicholas C. Dobes
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Alexandra J. Dickinson
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Philip C. Gach
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Pavak K. Shah
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 and North Carolina State University, Raleigh, NC 27695
| | - Nancy L. Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599 and North Carolina State University, Raleigh, NC 27695
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Takeda K. Microcoils and microsamples in solid-state NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 47-48:1-9. [PMID: 23083521 DOI: 10.1016/j.ssnmr.2012.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 06/01/2023]
Abstract
Recent reports on microcoils are reviewed. The first part of the review includes a discussion of how the geometries of the sample and coil affect the NMR signal intensity. In addition to derivation of the well-known result that the signal intensity increases as the coil size decreases, the prediction that dilution of a small sample with magnetically inert matter leads to better sensitivity if a tiny coil is not available is given. The second part of the review focuses on the issues specific to solid-state NMR. They include realization of magic-angle spinning (MAS) using a microcoil and harnessing of such strong pulses that are feasible only with a microcoil. Two strategies for microcoil MAS, the piggyback method and magic-angle coil spinning (MACS), are reviewed. In addition, MAS of flat, disk-shaped samples is discussed in the context of solid-state NMR of small-volume samples. Strong RF irradiation, which has been exploited in wide-line spectral excitation, multiple-quantum MAS (MQMAS), and dipolar decoupling experiments, has been accompanied by new challenges regarding the Bloch-Siegert effect, the minimum time resolution of the spectrometer, and the time scale of pulse transient effects. For a possible solution to the latter problem, recent reports on active compensation of pulse transients are described.
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Affiliation(s)
- Kazuyuki Takeda
- Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
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