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Enhanced spatial resolution in magnetic resonance imaging by dynamic nuclear polarization at 5 K. Proc Natl Acad Sci U S A 2022; 119:e2201644119. [PMID: 35605126 DOI: 10.1073/pnas.2201644119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceAlthough MRI is a powerful method for visualizing features within organisms and materials, the relatively low signal-to-noise ratio (SNR) of the NMR signals that are used to construct an image makes MRI with isotropic spatial resolution below 3.0 μm impractical at room temperature. Here we show that SNR enhancements available from a combination of low temperatures and dynamic nuclear polarization allow MRI with 1.7-μm isotropic resolution. These results may enable informative MRI studies of eukaryotic cells, cell clusters, and small tissue samples.
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Kupče Ē, Mote KR, Webb A, Madhu PK, Claridge TDW. Multiplexing experiments in NMR and multi-nuclear MRI. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 124-125:1-56. [PMID: 34479710 DOI: 10.1016/j.pnmrs.2021.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 02/28/2021] [Accepted: 03/02/2021] [Indexed: 05/22/2023]
Abstract
Multiplexing NMR experiments by direct detection of multiple free induction decays (FIDs) in a single experiment offers a dramatic increase in the spectral information content and often yields significant improvement in sensitivity per unit time. Experiments with multi-FID detection have been designed with both homonuclear and multinuclear acquisition, and the advent of multiple receivers on commercial spectrometers opens up new possibilities for recording spectra from different nuclear species in parallel. Here we provide an extensive overview of such techniques, designed for applications in liquid- and solid-state NMR as well as in hyperpolarized samples. A brief overview of multinuclear MRI is also provided, to stimulate cross fertilization of ideas between the two areas of research (NMR and MRI). It is shown how such techniques enable the design of experiments that allow structure elucidation of small molecules from a single measurement. Likewise, in biomolecular NMR experiments multi-FID detection allows complete resonance assignment in proteins. Probes with multiple RF microcoils routed to multiple NMR receivers provide an alternative way of increasing the throughput of modern NMR systems, effectively reducing the cost of NMR analysis and increasing the information content at the same time. Solid-state NMR experiments have also benefited immensely from both parallel and sequential multi-FID detection in a variety of multi-dimensional pulse schemes. We are confident that multi-FID detection will become an essential component of future NMR methodologies, effectively increasing the sensitivity and information content of NMR measurements.
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Affiliation(s)
- Ēriks Kupče
- Bruker UK Ltd., Banner Lane, Coventry CV4 9GH, United Kingdom.
| | - Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research-Hyderabad, 36/P Gopanpally Village, Ranga Reddy District, Hyderabad 500 046, Telangana, India
| | - Andrew Webb
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, Netherlands
| | - Perunthiruthy K Madhu
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research-Hyderabad, 36/P Gopanpally Village, Ranga Reddy District, Hyderabad 500 046, Telangana, India
| | - Tim D W Claridge
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK
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Kupče Ē, Frydman L, Webb AG, Yong JRJ, Claridge TDW. Parallel nuclear magnetic resonance spectroscopy. ACTA ACUST UNITED AC 2021. [DOI: 10.1038/s43586-021-00024-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Chen HY, Tycko R. Low-temperature magnetic resonance imaging with 2.8 μm isotropic resolution. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 287:47-55. [PMID: 29288890 PMCID: PMC5803441 DOI: 10.1016/j.jmr.2017.12.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 05/16/2023]
Abstract
We demonstrate the feasibility of high-resolution 1H magnetic resonance imaging (MRI) at low temperatures by obtaining an MRI image of 20 μm diameter glass beads in glycerol/water at 28 K with 2.8 μm isotropic resolution. The experiments use a recently-described MRI apparatus (Moore and Tycko, 2015) with minor modifications. The sample is contained within a radio-frequency microcoil with 150 μm inner diameter. Sensitivity is additionally enhanced by paramagnetic doping, optimization of the sample temperature, three-dimensional phase-encoding of k-space data, pulsed spin-lock detection of 1H nuclear magnetic resonance signals, and spherical sampling of k-space. We verify that the actual image resolution is 2.7 ± 0.3 μm by quantitative comparisons of experimental and calculated images. Our imaging approach is compatible with dynamic nuclear polarization, providing a path to significantly higher resolution in future experiments.
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Affiliation(s)
- Hsueh-Ying Chen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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Heo P, Seo JH, Han SD, Ryu Y, Byun JD, Kim KN, Lee JH. Multi-port-driven birdcage coil for multiple-mouse MR imaging at 7 T. SCANNING 2016; 38:747-756. [PMID: 27162104 DOI: 10.1002/sca.21324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
In ultra-high field (UHF) imaging environments, it has been demonstrated that multiple-mouse magnetic resonance imaging (MM-MRI) is dependent on key factors such as the radiofrequency (RF) coil hardware, imaging protocol, and experimental setup for obtaining high-resolution MR images. A key aspect is the RF coil, and a number of MM-MRI studies have investigated the application of single-channel RF transmit (Tx)/receive (Rx) coils or multi-channel phased array (PA) coil configurations under a single gradient coil set. However, despite applying a variety of RF coils, Tx (|B1+ |)-field inhomogeneity still remains a major problem due to the relative shortening of the effective RF wavelength in the UHF environment. To address this issue, we propose a relatively smaller size of individual Tx-only coils in a multiple birdcage (MBC) coil for MM-MRI to image up to three mice. We use electromagnetic (EM) simulations in the finite-difference time-domain (FDTD) environment to obtain the |B1 |-field distribution. Our results clearly show that the single birdcage (SBC) high-pass filter (HPF) configuration, which is referred to as the SBCHPF , under the absence of an RF shield exhibits a high |B1 |-field intensity in comparison with other coil configurations such as the low-pass filter (LPF) and band-pass filter (BPF) configurations. In a 7-T MRI experiment, the signal-to-noise ratio (SNR) map of the SBCHPF configuration shows the highest coil performance compared to other coil configurations. The MBCHPF coil, which is comprised of a triple-SBCHPF configuration combined with additional decoupling techniques, is developed for simultaneous image acquisition of three mice. SCANNING 38:747-756, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Phil Heo
- Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
| | - Jeung-Hoon Seo
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Sang-Doc Han
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Yeunchul Ryu
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - Jong-Deok Byun
- Department of Mechanical and Biomedical Engineering, Gangwon University, Gangwon, Korea
| | - Kyoung-Nam Kim
- Neuroscience Research Institute, Gachon University, Incheon, Korea
- Department of Biomedical Engineering, Gachon University, Incheon, Korea
| | - Jung Hee Lee
- Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Moore E, Tycko R. Micron-scale magnetic resonance imaging of both liquids and solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:1-9. [PMID: 26397215 PMCID: PMC4628880 DOI: 10.1016/j.jmr.2015.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 05/16/2023]
Abstract
We describe and demonstrate a novel apparatus for magnetic resonance imaging (MRI), suitable for imaging of both liquid and solid samples with micron-scale isotropic resolution. The apparatus includes a solenoidal radio-frequency microcoil with 170 μm inner diameter and a set of planar gradient coils, all wound by hand and supported on a series of stacked sapphire plates. The design ensures efficient heat dissipation during gradient pulses and also facilitates disassembly, sample changes, and reassembly. To demonstrate liquid state (1)H MRI, we present an image of polystyrene beads within CuSO4-doped water, contained within a capillary tube with 100 μm inner diameter, with 5.0 μm isotropic resolution. To demonstrate solid state (1)H MRI, we present an image of NH4Cl particles within the capillary tube, with 8.0 μm isotropic resolution. High-resolution solid state MRI is enabled by frequency-switched Lee-Goldburg decoupling, with an effective rotating frame field amplitude of 289 kHz. At room temperature, pulsed gradients of 4 T/m (i.e., 170 Hz/μm for (1)H MRI) are achievable in all three directions with currents of 10 A or less. The apparatus is contained within a variable-temperature liquid helium cryostat, which will allow future efforts to obtain MRI images at low temperatures with signal enhancement by dynamic nuclear polarization.
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Affiliation(s)
- Eric Moore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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Anders J, SanGiorgio P, Boero G. A fully integrated IQ-receiver for NMR microscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 209:1-7. [PMID: 21257327 DOI: 10.1016/j.jmr.2010.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 05/30/2023]
Abstract
We present a fully integrated CMOS receiver for micro-magnetic resonance imaging together with a custom-made micro-gradient system. The receiver is designed for an operating frequency of 300 MHz. The chip consists of an on-chip detection coil and tuning capacitor as well as a low-noise amplifier and a quadrature downconversion mixer with corresponding low-frequency amplification stages. The design is realized in a 0.13 μm CMOS technology, it occupies a chip area of 950 × 800 μm² and it draws 50 mA from a supply voltage of 1.8 V. The achieved time-domain spin sensitivity is 5×10(14)spins/Hz. Images of phantoms obtained in our custom-made gradient system with 8 μm isotropic resolution are reported.
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Affiliation(s)
- Jens Anders
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne, Switzerland.
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Mohmmadzadeh M, Baxan N, Badilita V, Kratt K, Weber H, Korvink JG, Wallrabe U, Hennig J, von Elverfeldt D. Characterization of a 3D MEMS fabricated micro-solenoid at 9.4 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 208:20-26. [PMID: 21071246 DOI: 10.1016/j.jmr.2010.09.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 09/25/2010] [Accepted: 09/29/2010] [Indexed: 05/30/2023]
Abstract
We present for the first time a complete characterization of a micro-solenoid for high resolution MR imaging of mass- and volume-limited samples based on three-dimensional B(0), B(1) per unit current (B(1)(unit)) and SNR maps. The micro-solenoids are fabricated using a fully micro-electromechanical systems (MEMS) compatible process in conjunction with an automatic wire-bonder. We present 15 μm isotropic resolution 3D B(0) maps performed using the phase difference method. The resulting B(0) variation in the range of [-0.07 ppm to -0.157 ppm] around the coil center, compares favorably with the 0.5 ppm limit accepted for MR microscopy. 3D B(1)(unit) maps of 40 μm isotropic voxel size were acquired according to the extended multi flip angle (ExMFA) method. The results demonstrate that the characterized microcoil provides a high and uniform sensitivity distribution around its center (B(1)(unit) = 3.4 mT/A ± 3.86%) which is in agreement with the corresponding 1D theoretical data computed along the coil axis. The 3D SNR maps reveal a rather uniform signal distribution around the coil center with a mean value of 53.69 ± 19%, in good agreement with the analytical 1D data along coil axis in the axial slice. Finally, we prove the microcoil capabilities for MR microscopy by imaging Eremosphaera viridis cells with 18 μm isotropic resolution.
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Affiliation(s)
- M Mohmmadzadeh
- Department of Radiology, University Hospital Freiburg, Germany.
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Anders J, Chiaramonte G, SanGiorgio P, Boero G. A single-chip array of NMR receivers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 201:239-249. [PMID: 19836280 DOI: 10.1016/j.jmr.2009.09.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 09/17/2009] [Accepted: 09/27/2009] [Indexed: 05/28/2023]
Abstract
We present the first single-chip array of integrated NMR receivers for parallel spectroscopy and imaging. The array, optimized for operation at 300 MHz, is composed of eight separate channels, with each channel consisting of a detection coil, a tuning capacitor, a low noise amplifier and a 50 ohm buffer. As all the integrated electronics are placed underneath the reception coils, the array is densely packed. Each single-channel reception coil has a diameter of 500 microm, resulting in a total active area of 1 mm by 2 mm for the array. The (1)H time-domain spin sensitivity of a single channel is approximately 1x10(15) spins/square root(Hz).
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Affiliation(s)
- Jens Anders
- Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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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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Moco S, Schneider B, Vervoort J. Plant Micrometabolomics: The Analysis of Endogenous Metabolites Present in a Plant Cell or Tissue. J Proteome Res 2009; 8:1694-703. [DOI: 10.1021/pr800973r] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Sofia Moco
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, and Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
| | - Bernd Schneider
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, and Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
| | - Jacques Vervoort
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, and Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
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Mietchen D, Manz B, Volke F, Storey K. In vivo assessment of cold adaptation in insect larvae by magnetic resonance imaging and magnetic resonance spectroscopy. PLoS One 2008; 3:e3826. [PMID: 19057644 PMCID: PMC2586655 DOI: 10.1371/journal.pone.0003826] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 11/04/2008] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Temperatures below the freezing point of water and the ensuing ice crystal formation pose serious challenges to cell structure and function. Consequently, species living in seasonally cold environments have evolved a multitude of strategies to reorganize their cellular architecture and metabolism, and the underlying mechanisms are crucial to our understanding of life. In multicellular organisms, and poikilotherm animals in particular, our knowledge about these processes is almost exclusively due to invasive studies, thereby limiting the range of conclusions that can be drawn about intact living systems. METHODOLOGY Given that non-destructive techniques like (1)H Magnetic Resonance (MR) imaging and spectroscopy have proven useful for in vivo investigations of a wide range of biological systems, we aimed at evaluating their potential to observe cold adaptations in living insect larvae. Specifically, we chose two cold-hardy insect species that frequently serve as cryobiological model systems--the freeze-avoiding gall moth Epiblema scudderiana and the freeze-tolerant gall fly Eurosta solidaginis. RESULTS In vivo MR images were acquired from autumn-collected larvae at temperatures between 0 degrees C and about -70 degrees C and at spatial resolutions down to 27 microm. These images revealed three-dimensional (3D) larval anatomy at a level of detail currently not in reach of other in vivo techniques. Furthermore, they allowed visualization of the 3D distribution of the remaining liquid water and of the endogenous cryoprotectants at subzero temperatures, and temperature-weighted images of these distributions could be derived. Finally, individual fat body cells and their nuclei could be identified in intact frozen Eurosta larvae. CONCLUSIONS These findings suggest that high resolution MR techniques provide for interesting methodological options in comparative cryobiological investigations, especially in vivo.
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Affiliation(s)
- Daniel Mietchen
- Magnetic Resonance Group, Fraunhofer Institute for Biomedical Engineering, IBMT, St Ingbert, Germany.
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Marquardsen T, Hofmann M, Hollander JG, Loch CMP, Kiihne SR, Engelke F, Siegal G. Development of a dual cell, flow-injection sample holder, and NMR probe for comparative ligand-binding studies. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 182:55-65. [PMID: 16814582 DOI: 10.1016/j.jmr.2006.05.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 05/04/2006] [Accepted: 05/15/2006] [Indexed: 05/10/2023]
Abstract
NMR based ligand screening is becoming increasingly important for the very early stages of drug discovery. We have proposed a method that makes highly efficient use of a single sample of a scarce target, or one with poor or limited solubility, to screen an entire compound library. This comparative method is based on immobilizing the target for the screening procedure. In order to support the method, a dual cell, flow injection probe with a single receiver coil has been constructed. The flow injection probe has been mated to a single high performance pump and sample handling system to enable the automated analysis of large numbers of compound mixes for binding to the target. The probe, having an 8 mm 1H/2H dual tuned coil and triple axis gradients, is easily shimmed and yields NMR spectra of comparable quality to a standard 5 mm high-resolution probe. The lineshape in the presence of a solid support is identical to that in glass NMR tubes in a 5 mm probe. Control spectra of each cell are identical and well separated, while ligand binding in a complex mixture can be readily detected in 20-30 min, thus paving the way for use of the probe for actual drug discovery efforts.
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Murali N, Miller WM, John BK, Avizonis DA, Smallcombe SH. Spectral unraveling by space-selective Hadamard spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 179:182-9. [PMID: 16364668 DOI: 10.1016/j.jmr.2005.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 11/29/2005] [Accepted: 11/29/2005] [Indexed: 05/05/2023]
Abstract
Spectral unraveling by space-selective Hadamard spectroscopy (SUSHY) enables recording of NMR spectra of multiple samples loaded in multiple sample tubes in a modified spinner turbine and a regular 5mm liquids NMR probe equipped with a tri-axis pulsed field gradient coil. The individual spectrum from each sample is extracted by adding and subtracting data that are simultaneously obtained from all the tubes based on the principles of spatially resolved Hadamard spectroscopy. The well-known Hadamard spectroscopy has been applied for spatial selection and the method utilizes standard configuration of NMR instrument hardware. The SUSHY method can be easily incorporated in multi-dimensional multi-tube NMR experiments. This method combines the excitation multiplexing, natural advantage of FTNMR, and sample multiplexing and offers high-throughput by reducing the total experimental time by up to a factor of four in a 4-tube mode.
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Webb AG. Microcoil nuclear magnetic resonance spectroscopy. J Pharm Biomed Anal 2005; 38:892-903. [PMID: 16087050 DOI: 10.1016/j.jpba.2005.01.048] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Revised: 01/15/2005] [Accepted: 01/22/2005] [Indexed: 11/16/2022]
Abstract
In comparison with most analytical chemistry techniques, nuclear magnetic resonance has an intrinsically low sensitivity, and many potential applications are therefore precluded by the limited available quantity of certain types of sample. In recent years, there has been a trend, both commercial and academic, towards miniaturization of the receiver coil in order to increase the mass sensitivity of NMR measurements. These small coils have also proved very useful in coupling NMR detection with commonly used microseparation techniques. A further development enabled by small detectors is parallel data acquisition from many samples simultaneously, made possible by incorporating multiple receiver coils into a single NMR probehead. This review article summarizes recent developments and applications of "microcoil" NMR spectroscopy.
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Affiliation(s)
- A G Webb
- Department of Electrical and Computer Engineering, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 4221 Beckman Institute, 405 N. Mathews, Urbana, IL 61801, USA.
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