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Merz S, Wang J, Galvosas P, Granwehr J. MAS-NMR of [Pyr 13][Tf 2N] and [Pyr 16][Tf 2N] Ionic Liquids Confined to Carbon Black: Insights and Pitfalls. Molecules 2021; 26:6690. [PMID: 34771100 PMCID: PMC8587276 DOI: 10.3390/molecules26216690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/16/2022] Open
Abstract
Electrolytes based on ionic liquids (IL) are promising candidates to replace traditional liquid electrolytes in electrochemical systems, particularly in combination with carbon-based porous electrodes. Insight into the dynamics of such systems is imperative for tailoring electrochemical performance. In this work, 1-Methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-Hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide were studied in a carbon black (CB) host using spectrally resolved Carr-Purcell-Meiboom-Gill (CPMG) and 13-interval Pulsed Field Gradient Stimulated Echo (PFGSTE) Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR). Data were processed using a sensitivity weighted Laplace inversion algorithm without non-negativity constraint. Previously found relations between the alkyl length and the aggregation behavior of pyrrolidinium-based cations were confirmed and characterized in more detail. For the IL in CB, a different aggregation behavior was found compared to the neat IL, adding the surface of a porous electrode as an additional parameter for the optimization of IL-based electrolytes. Finally, the suitability of MAS was assessed and critically discussed for investigations of this class of samples.
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Affiliation(s)
- Steffen Merz
- Fundamental Electrochemistry (IEK-9), Institute of Energy and Climate Research, Forschungszentrum Juelich, 52425 Juelich, Germany; (S.M.); (J.G.)
| | - Jie Wang
- MacDiamid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University Wellington, Wellington 6140, New Zealand;
| | - Petrik Galvosas
- MacDiamid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University Wellington, Wellington 6140, New Zealand;
| | - Josef Granwehr
- Fundamental Electrochemistry (IEK-9), Institute of Energy and Climate Research, Forschungszentrum Juelich, 52425 Juelich, Germany; (S.M.); (J.G.)
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, 52056 Aachen, Germany
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Modo M. 19F Magnetic Resonance Imaging and Spectroscopy in Neuroscience. Neuroscience 2021; 474:37-50. [PMID: 33766776 DOI: 10.1016/j.neuroscience.2021.03.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/23/2022]
Abstract
1H magnetic resonance imaging (MRI) has established itself as a key diagnostic technique, affording the visualization of brain anatomy, blood flow, activity and connectivity. The detection of other atoms (e.g. 19F, 23Na, 31P), so called hetero-nuclear MRI and spectroscopy (MRS), provides investigative avenues that complement and extend the richness of information that can be gained from 1H MRI. Especially 19F MRI is increasingly emerging as a multi-nuclear (1H/19F) technique that can be exploited to visualize cell migration and trafficking. The lack of a 19F background signal in the brain affords an unequivocal detection suitable for quantification. Fluorine-based contrast material can be engineered as nanoemulsions, nanocapsules, or nanoparticles to label cells in vitro or in vivo. Fluorinated blood substitutes, typically nanoemulsions, can also carry oxygen and serve as a theranostic in poorly perfused brain regions. Brain tissue concentrations of fluorinated pharmaceuticals, including inhalation anesthetics (e.g. isoflurane) and anti-depressants (e.g. fluoxetine), can also be measured using MRS. However, the low signal from these compounds provides a challenge for imaging. Further methodological advances that accelerate signal acquisition (e.g. compressed sensing, cryogenic coils) are required to expand the applications of 19F MR imaging to, for instance, determine the regional pharmacokinetics of novel fluorine-based drugs. Improvements in 19F signal detection and localization, combined with the development of novel sensitive probes, will increase the utility of these multi-nuclear studies. These advances will provide new insights into cellular and molecular processes involved in neurodegenerative disease, as well as the mode of action of pharmaceutical compounds.
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Affiliation(s)
- Michel Modo
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Ghuman H, Hitchens TK, Modo M. A systematic optimization of 19F MR image acquisition to detect macrophage invasion into an ECM hydrogel implanted in the stroke-damaged brain. Neuroimage 2019; 202:116090. [PMID: 31408717 DOI: 10.1016/j.neuroimage.2019.116090] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 08/06/2019] [Accepted: 08/08/2019] [Indexed: 02/08/2023] Open
Abstract
19F-MR imaging of perfluorocarbon (PFC)-labeled macrophages can provide a unique insight into their participation and spatio-temporal dynamics of inflammatory events, such as the biodegradation of an extracellular matrix (ECM) hydrogel implanted into a stroke cavity. To determine the most efficient acquisition strategy for 19F-MR imaging, five commonly used sequences were optimized using a design of experiment (DoE) approach and compared based on their signal-to-noise ratio (SNR). The fast imaging with steady-state precession (FISP) sequence produced the most efficient detection of a 19F signal followed by the rapid acquisition with relaxation enhancement (RARE) sequence. The multi-slice multi-echo (MSME), fast low angle shot (FLASH), and zero echo time (ZTE) sequences were significantly less efficient. Imaging parameters (matrix/voxel size; slice thickness, number of averages) determined the accuracy (i.e. trueness and precision) of object identification by reducing partial volume effects, as determined by analysis of the point spread function (PSF). A 96 × 96 matrix size (0.35 mm3) produced the lowest limit of detection (LOD) for RARE (2.85 mM PFPE; 119 mM 19F) and FISP (0.43 mM PFPE; 18.1 mM 19F), with an SNR of 2 as the detection threshold. Imaging of a brain phantom with PFC-labeled macrophages invading an ECM hydrogel further illustrated the impact of these parameter changes. The systematic optimization of sequence and imaging parameters provides the framework for an accurate visualization of 19F-labeled macrophage distribution and density in the brain. This will enhance our understanding of the contribution of periphery-derived macrophages in bioscaffold degradation and its role in brain tissue regeneration.
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Affiliation(s)
- Harmanvir Ghuman
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - T Kevin Hitchens
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michel Modo
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
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Fluorine-19 Cellular MRI Detection of In Vivo Dendritic Cell Migration and Subsequent Induction of Tumor Antigen-Specific Immunotherapeutic Response. Mol Imaging Biol 2019; 22:549-561. [DOI: 10.1007/s11307-019-01393-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Accelerated 19F·MRI Detection of Matrix Metalloproteinase-2/-9 through Responsive Deactivation of Paramagnetic Relaxation Enhancement. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:4826520. [PMID: 30944549 PMCID: PMC6421815 DOI: 10.1155/2019/4826520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 12/10/2018] [Indexed: 01/12/2023]
Abstract
Paramagnetic gadolinium ions (GdIII), complexed within DOTA-based chelates, have become useful tools to increase the magnetic resonance imaging (MRI) contrast in tissues of interest. Recently, "on/off" probes serving as 19F·MRI biosensors for target enzymes have emerged that utilize the increase in transverse (T 2 ∗ or T 2) relaxation times upon cleavage of the paramagnetic GdIII centre. Molecular 19F·MRI has the advantage of high specificity due to the lack of background signal but suffers from low signal intensity that leads to low spatial resolution and long recording times. In this work, an "on/off" probe concept is introduced that utilizes responsive deactivation of paramagnetic relaxation enhancement (PRE) to generate 19F longitudinal (T 1) relaxation contrast for accelerated molecular MRI. The probe concept is applied to matrix metalloproteinases (MMPs), a class of enzymes linked with many inflammatory diseases and cancer that modify bioactive extracellular substrates. The presence of these biomarkers in extracellular space makes MMPs an accessible target for responsive PRE deactivation probes. Responsive PRE deactivation in a 19F biosensor probe, selective for MMP-2 and MMP-9, is shown to enable molecular MRI contrast at significantly reduced experimental times compared to previous methods. PRE deactivation was caused by MMP through cleavage of a protease substrate that served as a linker between the fluorine-containing moiety and a paramagnetic GdIII-bound DOTA complex. Ultrashort echo time (UTE) MRI and, alternatively, short echo times in standard gradient echo (GE) MRI were employed to cope with the fast 19F transverse relaxation of the PRE active probe in its "on-state." Upon responsive PRE deactivation, the 19F·MRI signal from the "off-state" probe diminished, thereby indicating the presence of the target enzyme through the associated negative MRI contrast. Null point 1H·MRI, obtainable within a short time course, was employed to identify false-positive 19F·MRI responses caused by dilution of the contrast agent.
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Preclinical 19F MRI cell tracking at 3 Tesla. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2018; 32:123-132. [DOI: 10.1007/s10334-018-0715-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/06/2018] [Accepted: 10/27/2018] [Indexed: 01/11/2023]
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Fu C, Zhang C, Peng H, Han F, Baker C, Wu Y, Ta H, Whittaker AK. Enhanced Performance of Polymeric 19F MRI Contrast Agents through Incorporation of Highly Water-Soluble Monomer MSEA. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01190] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Waiczies S, Millward JM, Starke L, Delgado PR, Huelnhagen T, Prinz C, Marek D, Wecker D, Wissmann R, Koch SP, Boehm-Sturm P, Waiczies H, Niendorf T, Pohlmann A. Enhanced Fluorine-19 MRI Sensitivity using a Cryogenic Radiofrequency Probe: Technical Developments and Ex Vivo Demonstration in a Mouse Model of Neuroinflammation. Sci Rep 2017; 7:9808. [PMID: 28851959 PMCID: PMC5575026 DOI: 10.1038/s41598-017-09622-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/19/2017] [Indexed: 11/10/2022] Open
Abstract
Neuroinflammation can be monitored using fluorine-19 (19F)-containing nanoparticles and 19F MRI. Previously we studied neuroinflammation in experimental autoimmune encephalomyelitis (EAE) using room temperature (RT) 19F radiofrequency (RF) coils and low spatial resolution 19F MRI to overcome constraints in signal-to-noise ratio (SNR). This yielded an approximate localization of inflammatory lesions. Here we used a new 19F transceive cryogenic quadrature RF probe ( 19 F-CRP) that provides the SNR necessary to acquire superior spatially-resolved 19F MRI. First we characterized the signal-transmission profile of the 19 F-CRP. The 19 F-CRP was then benchmarked against a RT 19F/1H RF coil. For SNR comparison we used reference compounds including 19F-nanoparticles and ex vivo brains from EAE mice administered with 19F-nanoparticles. The transmit/receive profile of the 19 F-CRP diminished with increasing distance from the surface. This was counterbalanced by a substantial SNR gain compared to the RT coil. Intraparenchymal inflammation in the ex vivo EAE brains was more sharply defined when using 150 μm isotropic resolution with the 19 F-CRP, and reflected the known distribution of EAE histopathology. At this spatial resolution, most 19F signals were undetectable using the RT coil. The 19 F-CRP is a valuable tool that will allow us to study neuroinflammation with greater detail in future in vivo studies.
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Affiliation(s)
- Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
| | - Jason M Millward
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Ludger Starke
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Paula Ramos Delgado
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Christian Prinz
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | | | | | | | - Stefan P Koch
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité Core Facility 7T Experimental MRIs, and NeuroCure, Charité University Medicine Berlin, Berlin, Germany
| | - Philipp Boehm-Sturm
- Department of Experimental Neurology, Center for Stroke Research Berlin (CSB), Charité Core Facility 7T Experimental MRIs, and NeuroCure, Charité University Medicine Berlin, Berlin, Germany
| | | | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- MRI TOOLS GmbH, Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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