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Cui X, Zhang Z, Yang Y, Li S, Lee C. Organic radical materials in biomedical applications: State of the art and perspectives. EXPLORATION (BEIJING, CHINA) 2022; 2:20210264. [PMID: 37323877 PMCID: PMC10190988 DOI: 10.1002/exp.20210264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/24/2022] [Indexed: 06/17/2023]
Abstract
Owing to their unique chemical reactivities and paramagnetism, organic radicals with unpaired electrons have found widespread exploration in physical, chemical, and biological fields. However, most radicals are too short-lived to be separated and only a few of them can maintain stable radical forms via stereochemical strategies. How to utilize these raw radicals for developing stable radical-containing materials have long been a research hotspot for many years. This perspective introduces fundamental characteristics of organic radical materials and highlights their applications in biomedical fields, particularly for bioimaging, biosensing, and photo-triggered therapies. Molecular design of these radical materials is considered with reference to their outstanding imaging and therapeutic performances. Various challenges currently limiting the wide applications of these organic radical materials and their future development are also discussed.
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Affiliation(s)
- Xiao Cui
- Department of ChemistryInstitution Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongKowloonHong Kong SARChina
| | - Zhen Zhang
- Department of ChemistryInstitution Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongKowloonHong Kong SARChina
| | - Yuliang Yang
- College of Pharmaceutical SciencesSoochow UniversitySuzhouChina
| | - Shengliang Li
- College of Pharmaceutical SciencesSoochow UniversitySuzhouChina
| | - Chun‐Sing Lee
- Department of ChemistryInstitution Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongKowloonHong Kong SARChina
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Kimura K, Iguchi N, Nakano H, Yasui H, Matsumoto S, Inanami O, Hirata H. Redox-Sensitive Mapping of a Mouse Tumor Model Using Sparse Projection Sampling of Electron Paramagnetic Resonance. Antioxid Redox Signal 2022; 36:57-69. [PMID: 33847172 PMCID: PMC8823265 DOI: 10.1089/ars.2021.0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aims: This work aimed to establish an accelerated imaging system for redox-sensitive mapping in a mouse tumor model using electron paramagnetic resonance (EPR) and nitroxyl radicals. Results: Sparse sampling of EPR spectral projections was demonstrated for a solution phantom. The reconstructed three-dimensional (3D) images with filtered back-projection (FBP) and compressed sensing image reconstruction were quantitatively assessed for the solution phantom. Mouse xenograft models of a human-derived pancreatic ductal adenocarcinoma cell line, MIA PaCa-2, were also measured for redox-sensitive mapping with the sparse sampling technique. Innovation: A short-lifetime redox-sensitive nitroxyl radical (15N-labeled perdeuterated Tempone) could be measured to map the decay rates of the EPR signals for the mouse xenograft models. Acceleration of 3D EPR image acquisition broadened the choices of nitroxyl radical probes with various redox sensitivities to biological environments. Conclusion: Sparse sampling of EPR spectral projections accelerated image acquisition in the 3D redox-sensitive mapping of mouse tumor-bearing legs fourfold compared with conventional image acquisition with FBP. Antioxid. Redox Signal. 36, 57-69.
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Affiliation(s)
- Kota Kimura
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Nami Iguchi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Hitomi Nakano
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
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3
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Weaver J, Liu KJ. A Review of Low-Frequency EPR Technology for the Measurement of Brain pO2 and Oxidative Stress. APPLIED MAGNETIC RESONANCE 2021; 52:1379-1394. [PMID: 35340811 PMCID: PMC8945541 DOI: 10.1007/s00723-021-01384-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/24/2021] [Accepted: 06/30/2021] [Indexed: 06/14/2023]
Abstract
EPR can uniquely measure paramagnetic species. Although commercial EPR was introduced in 1950s, the early studies were mostly restricted to chemicals in solution or cellular experiments using X-band EPR equipment. Due to its limited penetration (<1 mm), experiments with living animals were almost impossible. To overcome these difficulties, Swartz group, along with several other leaders in field, pioneered the technology of low frequency EPR (e.g., L-band, 1-2 GHz). The development of low frequency EPR and the associated probes have dramatically expanded the application of EPR technology into the biomedical research field, providing answers to important scientific questions by measuring specific parameters that are impossible or very difficult to obtain by other approaches. In this review, which is aimed at highlighting the seminal contribution from Swartz group over the last several decades, we will focus on the development of EPR technology that was designed to deal with the potential challenges arising from conducting EPR spectroscopy in living animals. The second half of the review will be concentrated on the application of low frequency EPR in measuring cerebral tissue pO2 changes and oxidative stress in various physiological and pathophysiological conditions in the brain of animal disease models.
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Affiliation(s)
- John Weaver
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
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Samouilov A, Komarov D, Petryakov S, Iosilevich A, Zweier JL. Development of an L-band resonator optimized for fast scan EPR imaging of the mouse head. Magn Reson Med 2021; 86:2316-2327. [PMID: 33938574 PMCID: PMC8295191 DOI: 10.1002/mrm.28821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE To develop a novel resonator for high-quality fast scan electron paramagnetic resonance (EPR) and EPR/NMR co-imaging of the head and brain of mice at 1.25 GHz. METHODS Resonator dimensions were scaled to fit the mouse head with maximum filling factor. A single-loop 6-gap resonator of 20 mm diameter and 20 mm length was constructed. High resonator stability was achieved utilizing a fixed position double coupling loop. Symmetrical mutually inverted connections rendered it insensitive to field modulation and fast scan. Coupling adjustment was provided by a parallel-connected variable capacitor located at the feeding line at λ/4 distance. To minimize radiation loss, the shield around the resonator was supplemented with a planar conductive disc that focuses return magnetic flux. RESULTS Coupling of the resonator loaded with the mouse head was efficient and easy. This resonator enabled high-quality in vivo 3D EPR imaging of the mouse head following intravenous infusion of nitroxide probes. With this resonator and rapid scan EPR system, 4 ms scans were acquired in forward and reverse directions so that images with 2-scan 3,136 projections were acquired in 25 s. Head images were achieved with resolutions of 0.4 mm, enabling visualization of probe localization and uptake across the blood-brain barrier. CONCLUSIONS This resonator design provides good sensitivity, high stability, and B1 field homogeneity for in vivo fast scan EPR of the mouse head and brain, enabling faster measurements and higher resolution imaging of probe uptake, localization, and metabolism than previously possible.
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Affiliation(s)
- Alexandre Samouilov
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Denis Komarov
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Sergey Petryakov
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Arkadiy Iosilevich
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Jay L. Zweier
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
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5
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Emoto MC, Sato-Akaba H, Hamaue N, Kawanishi K, Koshino H, Shimohama S, Fujii HG. Early detection of redox imbalance in the APPswe/PS1dE9 mouse model of Alzheimer's disease by in vivo electron paramagnetic resonance imaging. Free Radic Biol Med 2021; 172:9-18. [PMID: 34058322 DOI: 10.1016/j.freeradbiomed.2021.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/14/2021] [Accepted: 05/25/2021] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is a common neurodegenerative disease that causes progressive cognitive decline. Deposition of amyloid-β (Aβ) peptides is the most important pathophysiological hallmark of AD. Oxidative stress induced by the generation of reactive oxygen species (ROS) is a prominent phenomenon in AD and is known to occur early in its course. Several reports have suggested a relationship between changes in redox status and AD pathology, including progressive Aβ deposition, glial cell activation, and inflammation. In the present study, we employed a newly designed three-dimensional continuous-wave digital electron paramagnetic resonance (EPR) imager with a blood-brain barrier (BBB)-permeable redox-sensitive piperidine nitroxide probe, 4-oxo-2,2,6,6-tetramethyl-piperidine-d16-1-oxyl, for early detection of changed brain redox status. Using this system, we noninvasively compared age-matched 7-month-old AD model mice with normal littermates (WT mice). The obtained brain redox images of AD and WT mice clearly showed impaired brain redox status of AD mice compared to WT, suggesting that oxidative damage had already increased in 7-month-old AD mice compared with age-matched WT mice. The pathological changes in 7-month-old mice in this study were detected earlier than in previous studies in which only AD mice older than 9 months of age could be imaged. Since EPR images suggested that oxidative damage was already increased in 7-month-old AD mice compared to age-matched WT mice, we also evaluated antioxidant levels and the activity of superoxide dismutase (SOD) in brain tissue homogenates of 7-month-old AD and WT mice. Compared to WT mice, decreased levels of glutathione and mitochondrial SOD activity were found in AD mice, which supports the EPR imaging results indicating impaired brain redox status. These results indicate that the EPR imaging method developed in this study is useful for early noninvasive detection of altered brain redox status due to oxidative disease.
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Affiliation(s)
- Miho C Emoto
- Department of Clinical Laboratory Science, School of Medical Technology, Health Sciences University of Hokkaido, Sapporo, Hokkaido, 002-8072, Japan
| | - Hideo Sato-Akaba
- Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Naoya Hamaue
- School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari, Hokkaido, 061-0293, Japan
| | - Katsuya Kawanishi
- Department of Removable Prosthodontics, School of Dentistry, Health Sciences University of Hokkaido, Ishikari, Hokkaido, 061-0293, Japan
| | - Hisashi Koshino
- Department of Removable Prosthodontics, School of Dentistry, Health Sciences University of Hokkaido, Ishikari, Hokkaido, 061-0293, Japan
| | - Shun Shimohama
- Department of Neurology, School of Medicine, Sapporo Medical University, Sapporo, Hokkaido, 060-8556, Japan
| | - Hirotada G Fujii
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Ishikari, Hokkaido, 061-0293, Japan.
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Komarov DA, Samouilov A, Hirata H, Zweier JL. High fidelity triangular sweep of the magnetic field for millisecond scan EPR imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 329:107024. [PMID: 34198184 PMCID: PMC8316393 DOI: 10.1016/j.jmr.2021.107024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/28/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
Linearity of the magnetic field sweep is important for high resolution continuous wave EPR imaging. Driving the field with triangular wave function is the most efficient way to scan EPR projections. However, the magnetic field sweep profile can be significantly distorted during fast millisecond projection scan. In this work, we introduce a method to generate highly linear and properly symmetrical triangular sweeps of the magnetic field using calibrated harmonics of the triangular wave function. First, the frequency response function of the EPR magnet and its power circuitry was obtained. For this, the field sweeping coil was driven with sinusoidal signals of different frequencies and the actual magnetic field inside the magnet was recorded. To cover wide range of frequencies, the measurements were carried out independently using gaussmeter, Hall-effect linear sensor integrated circuit, and an inductance coil. For each frequency, the system gain and the phase delay were determined. These data were used to adjust the amplitudes and the phases of individual harmonics of the triangular wave function. After the calibration, the maximum deviation of the magnetic field from the linear function was 0.05% of sweep width for 4 ms scan. The maximum discrepancy between the forward and the reverse scan was less than 0.04%. Sweep overhead time for changing the scan direction was 5%. The proposed approach allows generation of high fidelity triangular magnetic field sweeps with accuracy better than 0.1% for the range of the magnetic field sweep widths up to 48 G and scan duration from 10 s down to 1 ms.
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Affiliation(s)
- Denis A Komarov
- The EPR Center and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Alexandre Samouilov
- The EPR Center and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Jay L Zweier
- The EPR Center and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
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Matsumoto KI, Mitchell JB, Krishna MC. Multimodal Functional Imaging for Cancer/Tumor Microenvironments Based on MRI, EPRI, and PET. Molecules 2021; 26:1614. [PMID: 33799481 PMCID: PMC8002164 DOI: 10.3390/molecules26061614] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 11/23/2022] Open
Abstract
Radiation therapy is one of the main modalities to treat cancer/tumor. The response to radiation therapy, however, can be influenced by physiological and/or pathological conditions in the target tissues, especially by the low partial oxygen pressure and altered redox status in cancer/tumor tissues. Visualizing such cancer/tumor patho-physiological microenvironment would be a useful not only for planning radiotherapy but also to detect cancer/tumor in an earlier stage. Tumor hypoxia could be sensed by positron emission tomography (PET), electron paramagnetic resonance (EPR) oxygen mapping, and in vivo dynamic nuclear polarization (DNP) MRI. Tissue oxygenation could be visualized on a real-time basis by blood oxygen level dependent (BOLD) and/or tissue oxygen level dependent (TOLD) MRI signal. EPR imaging (EPRI) and/or T1-weighted MRI techniques can visualize tissue redox status non-invasively based on paramagnetic and diamagnetic conversions of nitroxyl radical contrast agent. 13C-DNP MRI can visualize glycometabolism of tumor/cancer tissues. Accurate co-registration of those multimodal images could make mechanisms of drug and/or relation of resulted biological effects clear. A multimodal instrument, such as PET-MRI, may have another possibility to link multiple functions. Functional imaging techniques individually developed to date have been converged on the concept of theranostics.
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Affiliation(s)
- Ken-ichiro Matsumoto
- Quantitative RedOx Sensing Group, Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, Quantum Medical Science Directorate, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - James B. Mitchell
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA;
| | - Murali C. Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA;
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Hyodo F, Ito S, Eto H, Elhelaly AE, Murata M, Akahoshi T, Utsumi H, Matuso M. Free radical imaging of endogenous redox molecules using dynamic nuclear polarisation magnetic resonance imaging. Free Radic Res 2020; 55:343-351. [PMID: 33307891 DOI: 10.1080/10715762.2020.1859109] [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: 10/22/2022]
Abstract
Redox reactions accompanied by the oxidation-reduction of endogenous molecules play important roles in maintaining homeostasis in living organisms. In humans, numerous endogenous molecules that contribute towards maintaining physiological conditions form free radicals via electron transfer. A typical example of this is the mitochondrial electron transport chain, which is involved in energy production. If free radicals derived from endogenous molecules could be visualised and exploited as biological and functional probes, redox reactions mediated by endogenous molecules could be detected non-invasively. We succeeded in visualising the free radicals derived from endogenous molecules using an in vivo dynamic nuclear polarisation (DNP) magnetic resonance imaging (MRI) system. In this review, we describe the visualisation of endogenous redox molecules, such as flavins and ubiquinones, which are mitochondrial electron carriers, as well as vitamin E and vitamin C (ascorbate). In addition, we describe the application of melanin free radicals for the in vivo visualisation of metabola without using probes via in vivo DNP-MRI.
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Affiliation(s)
- Fuminori Hyodo
- Department of Radiology, Frontier Science for Imaging, School of Medicine, Gifu University, Gifu, Japan
| | - Shinji Ito
- Center for Advanced Medical Open Innovation, Kyushu University, Fukuoka, Japan
| | - Hinako Eto
- Center for Advanced Medical Open Innovation, Kyushu University, Fukuoka, Japan
| | - Abdelazim Elsayed Elhelaly
- Department of Radiology, Gifu University, Gifu, Japan.,Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Suez Canal University, Ismalia, Egypt
| | - Masaharu Murata
- Center for Advanced Medical Open Innovation, Kyushu University, Fukuoka, Japan
| | - Tomohiko Akahoshi
- Graduate School of Medicine, Advanced Medical Medicine, Disaster and Emergency medicine, Kyushu University, Fukuoka, Japan
| | - Hideo Utsumi
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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Tseytlin O, Bobko AA, Tseytlin M. Rapid Scan EPR imaging as a Tool for Magnetic Field Mapping. APPLIED MAGNETIC RESONANCE 2020; 51:1117-1124. [PMID: 33642700 PMCID: PMC7909464 DOI: 10.1007/s00723-020-01238-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/24/2020] [Indexed: 06/05/2023]
Abstract
Functional four-dimensional spectral-spatial electron paramagnetic imaging (EPRI) is routinely used in biomedical research. Positions and widths of EPR lines in the spectral dimension report oxygen partial pressure, pH, and other important parameters of the tissue microenvironment. Images are measured in the homogeneous external magnetic field. An application of EPRI is proposed in which the field is perturbed by a magnetized object. A proof-of-concept imaging experiment was conducted, which permitted visualization of the magnetic field created by this object. A single-line lithium octa-n-butoxynaphthalocyanine spin probe was used in the experiment. The spectral position of the EPR line directly measured the strength of the perturbation field with spatial resolution. A three-dimensional magnetic field map was reconstructed as a result. Several applications of this technology can be anticipated. First is EPRI/MPI co-registration, where MPI is an emerging magnetic particle imaging technique. Second, EPRI can be an alternative to magnetic field cameras that are used for the development of high-end permanent magnets and their assemblies, consumer electronics, and industrial sensors. Besides the high resolution of magnetic field readings, EPR probes can be placed in the internal areas of various assemblies that are not accessible by the standard sensors. Third, EPRI can be used to develop systems for magnetic manipulation of cell cultures.
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Affiliation(s)
- Oxana Tseytlin
- Department of Biochemistry, West Virginia University,
Morgantown, WV 26506, USA
- In Vivo Multifunctional Magnetic Resonance center at Robert
C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506,
USA
| | - Andrey A. Bobko
- Department of Biochemistry, West Virginia University,
Morgantown, WV 26506, USA
- In Vivo Multifunctional Magnetic Resonance center at Robert
C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506,
USA
| | - Mark Tseytlin
- Department of Biochemistry, West Virginia University,
Morgantown, WV 26506, USA
- West Virginia University Cancer Institute, Morgantown, WV
26506, USA
- In Vivo Multifunctional Magnetic Resonance center at Robert
C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506,
USA
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Takeshita K, Okazaki H, Tsukamoto M, Okazaki S. Differences in pharmacokinetic behaviors of two lipophilic 3-substituted 2,2,5,5-tetramethylpyrrolidine-N-oxyl radicals, in vivo probes to assess the redox status in the brain using magnetic resonance techniques. Magn Reson Med 2020; 85:560-569. [PMID: 32905631 DOI: 10.1002/mrm.28499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/29/2020] [Accepted: 08/05/2020] [Indexed: 12/15/2022]
Abstract
PURPOSE The pharmacokinetics of 3-methoxycarbonyl- and 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl radicals (MCP and HMP, respectively), magnetic resonance probes to assess the brain redox status, were examined in healthy mouse brains. METHODS The time course of the concentration of the radical form of the probe in the brain was examined by signal enhancements on T1 -weighted MR image after an intravenous injection. The distribution of the total probe (sum of radical and reduced forms) was investigated using brain homogenates. RESULTS MCP distributed to the brain more than HMP. MCP exhibited biphasic decay with fast and slow components, whereas HMP exhibited monophasic decay with a similar rate constant to the slow component of MCP. Similar profiles were observed in various regions of the brain. The total probe for MCP exhibited monophasic decay at a similar rate constant to the slow component of the radical form; however, the initial content of the total probe was similar to its radical form. For HMP, decay of the total probe coincided with that of the radical form. CONCLUSION The decay of MCP needs to consider the reduction of the probe in and its elimination from the brain, while the decay of HMP may mainly result from its elimination from the brain.
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Affiliation(s)
- Keizo Takeshita
- Laboratory of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan.,DDS Research Institute, Sojo University, Kumamoto, Japan
| | - Hana Okazaki
- Laboratory of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
| | - Megumi Tsukamoto
- Laboratory of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
| | - Shoko Okazaki
- Laboratory of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
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Su Y, Bian S, Sawan M. Real-time in vivo detection techniques for neurotransmitters: a review. Analyst 2020; 145:6193-6210. [DOI: 10.1039/d0an01175d] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Functional synapses in the central nervous system depend on a chemical signal exchange process that involves neurotransmitter delivery between neurons and receptor cells in the neuro system.
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Affiliation(s)
- Yi Su
- Zhejiang university
- Hangzhou, 310058
- China
- CENBRAIN Lab
- School of Engineering
| | - Sumin Bian
- CENBRAIN Lab
- School of Engineering
- Westlake University
- Hangzhou
- China
| | - Mohamad Sawan
- CENBRAIN Lab
- School of Engineering
- Westlake University
- Hangzhou
- China
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12
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Sato-Akaba H, Tseytlin M. Development of an L-band rapid scan EPR digital console. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 304:42-52. [PMID: 31100585 PMCID: PMC7549020 DOI: 10.1016/j.jmr.2019.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 06/05/2023]
Abstract
The development of a digital console for in-vivo rapid scan electron paramagnetic resonance (RS-EPR) spectroscopy and imaging is described in detail. The console was build using field programmable gate array (FGPA) technology that permits real-time control of the resonator and scanning magnetic fields during the measurements. Automatic resonator tuning and matching are achieved by implementing a digital feedback control system and using voltage-tunable capacitors. A band-pass subsampling method is used to directly digitize EPR signals at the carrier frequencies of about 1.2 GHz. The magnetic field scan waveforms, excitation EPR frequency, and sampling clock are all internally synchronized. Full-cycle RS-EPR signals are accumulated in the FPGA in real time without any time gaps. The result is the elimination of the re-arm time, during which data are not acquired. The proposed design in this manuscript has a small footprint and is relatively low cost. The FPGA-based RS-EPR system was tested using standard LiNc-BuO and tempone-d16 samples. The RS-EPR linewidth of the LiNc-BuO sample was consistent with an independent pulsed EPR measurement.
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Affiliation(s)
- Hideo Sato-Akaba
- Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Mark Tseytlin
- Department of Biochemistry, School of Medicine, West Virginia University, Morgantown, WV, USA
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13
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Molecular Probes for Evaluation of Oxidative Stress by In Vivo EPR Spectroscopy and Imaging: State-of-the-Art and Limitations. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010013] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxidative stress, defined as a misbalance between the production of reactive oxygen species and the antioxidant defenses of the cell, appears as a critical factor either in the onset or in the etiology of many pathological conditions. Several methods of detection exist. However, they usually rely on ex vivo evaluation or reports on the status of living tissues only up to a few millimeters in depth, while a whole-body, real-time, non-invasive monitoring technique is required for early diagnosis or as an aid to therapy (to monitor the action of a drug). Methods based on electron paramagnetic resonance (EPR), in association with molecular probes based on aminoxyl radicals (nitroxides) or hydroxylamines especially, have emerged as very promising to meet these standards. The principles involve monitoring the rate of decrease or increase of the EPR signal in vivo after injection of the nitroxide or the hydroxylamine probe, respectively, in a pathological versus a control situation. There have been many successful applications in various rodent models. However, current limitations lie in both the field of the technical development of the spectrometers and the molecular probes. The scope of this review will mainly focus on the latter.
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Brain Redox Imaging Using In Vivo Electron Paramagnetic Resonance Imaging and Nitroxide Imaging Probes. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism. Under normal physiological conditions, oxidative damage is prevented by the regulation of ROS by the antioxidant network. However, increased ROS and decreased antioxidant defense may contribute to many brain disorders, such as stroke, Parkinson’s disease, and Alzheimer’s disease. Noninvasive assessment of brain redox status is necessary for monitoring the disease state and the oxidative damage. Continuous-wave electron paramagnetic resonance (CW-EPR) imaging using redox-sensitive imaging probes, such as nitroxides, is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. For conventional CW-EPR imaging, however, poor signal-to-noise ratio, low acquisition efficiency, and lack of anatomic visualization limit its ability to achieve three-dimensional redox mapping of small rodent brains. In this review, we discuss the instrumentation and coregistration of EPR images to anatomical images and appropriate nitroxide imaging probes, all of which are needed for a sophisticated in vivo EPR imager for all rodents. Using new EPR imaging systems, site-specific distribution and kinetics of nitroxide imaging probes in rodent brains can be obtained more accurately, compared to previous EPR imaging systems. We also describe the redox imaging studies of animal models of brain disease using newly developed EPR imaging.
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