1
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Petryakov SV, Kmiec MM, Ubert CS, Kassey VB, Schaner PE, Kuppusamy P. Surface dielectric resonator for in vivo EPR measurements. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 362:107690. [PMID: 38692250 PMCID: PMC11102834 DOI: 10.1016/j.jmr.2024.107690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/16/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
This research report describes a novel surface dielectric resonator (SDR) with a flexible connector for in vivo electron paramagnetic resonance (EPR) spectroscopy. Contrary to the conventional cavity or surface loop-gap resonators, the newly developed SDR is constructed from a ceramic dielectric material, and it is tuned to operate at the L-band frequency band (1.15 GHz) in continuous-wave mode. The SDR is designed to be critically coupled and capable of working with both very lossy samples, such as biological tissues, and non-lossy materials. The SDR was characterized using electromagnetic field simulations, assessed for sensitivity with a B1 field-perturbation method, and validated with tissue phantoms using EPR measurements. The results showed remarkably higher sensitivity in lossy tissue phantoms than the previously reported multisegment surface-loop resonators. The new SDR can provide potential new insights for advancements in the application of in vivo EPR spectroscopy for biological measurements, including clinical oximetry.
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Affiliation(s)
- Sergey V Petryakov
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Maciej M Kmiec
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Conner S Ubert
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Victor B Kassey
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Philip E Schaner
- Department of Radiation Oncology and Applied Sciences, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Periannan Kuppusamy
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; Department of Radiation Oncology and Applied Sciences, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
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2
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Nishi M, Hoshino N, Noro SI, Fujimoto H, Akutagawa T, Matsuda M. Dielectric and gas adsorption/desorption properties of x-Li(Pc) having one-dimensional channels surrounded by Pc˙ − columns. CrystEngComm 2020. [DOI: 10.1039/d0ce01157f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A one-dimensional channel system x-Li(Pc), composed of π-radical Pc˙−, was investigated. It was revealed that this channel surrounded by Li(Pc) columns is flexible, and gas adsorption/desorption measurements showed selective properties.
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Affiliation(s)
- Miki Nishi
- Department of Chemistry
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Norihisa Hoshino
- Institute of Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Shin-ichiro Noro
- Faculty of Environmental Earth Science
- Hokkaido University
- Sapporo 060-0810
- Japan
| | - Hitoshi Fujimoto
- Department of Chemistry
- Kumamoto University
- Kumamoto 860-8555
- Japan
| | - Tomoyuki Akutagawa
- Institute of Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Masaki Matsuda
- Department of Chemistry
- Kumamoto University
- Kumamoto 860-8555
- Japan
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3
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Miyakubo Y, Nishi M, Matsuda M. Fabrication of x‐Lithium Tetrabenzoporphyrin by One‐Pot Electrolysis Using
n
‐Butyllithium. ASIAN J ORG CHEM 2019. [DOI: 10.1002/ajoc.201900126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yusuke Miyakubo
- Department of ChemistryKumamoto University Kurokami 2–39-1 Kumamoto 860-8555 Japan
| | - Miki Nishi
- Department of ChemistryKumamoto University Kurokami 2–39-1 Kumamoto 860-8555 Japan
| | - Masaki Matsuda
- Department of ChemistryKumamoto University Kurokami 2–39-1 Kumamoto 860-8555 Japan
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4
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Laguta O, Tuček M, van Slageren J, Neugebauer P. Multi-frequency rapid-scan HFEPR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 296:138-142. [PMID: 30261338 DOI: 10.1016/j.jmr.2018.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
Gaining access to electron spin dynamics at (sub-)THz frequencies is highly challenging. However, this information is highly relevant for the understanding and development of spin polarization agents in dynamic nuclear polarization methods and single-molecule magnets for quantum computation. Here we demonstrate the first rapid-scan EPR experiment in 200 GHz frequency region. A voltage controlled oscillator (VCO) generated fast sinusoidal frequency sweeps with scan rates up to 3×105 THz/s after the frequency multiplication, which is equal to 107 T/s in field representation. Such high scan rates provide access to extremely short relaxation times T2=2π×sweeprate-0.5≈1 ns. The absence of a microwave cavity allowed us to perform multi-frequency experiments in the 170-250 GHz range. A further advantage of a cavity-less approach is the possibility to use vast sweeps, which in turn, allows the deconvolution using a linear sweep function. The deconvoluted spectra obtained with this method are identical to the slow-rate spectrum. We find spin-spin relaxation times of several nanoseconds for pure LiPc samples in this frequency range. These values cannot be obtained by means of conventional pulsed EPR methods.
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Affiliation(s)
- O Laguta
- Institute for Physical Chemistry and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
| | - M Tuček
- Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, Brno 61200, Czech Republic
| | - J van Slageren
- Institute for Physical Chemistry and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
| | - P Neugebauer
- Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, Brno 61200, Czech Republic.
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5
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Nezakati T, Seifalian A, Tan A, Seifalian AM. Conductive Polymers: Opportunities and Challenges in Biomedical Applications. Chem Rev 2018; 118:6766-6843. [DOI: 10.1021/acs.chemrev.6b00275] [Citation(s) in RCA: 354] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Toktam Nezakati
- Google Inc.., Mountain View, California 94043, United States
- Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London, London NW3 2QG, United Kingdom
| | - Amelia Seifalian
- UCL Medical School, University College London, London WC1E 6BT, United Kingdom
| | - Aaron Tan
- UCL Medical School, University College London, London WC1E 6BT, United Kingdom
| | - Alexander M. Seifalian
- NanoRegMed Ltd. (Nanotechnology and Regenerative Medicine Commercialization Centre), The London Innovation BioScience Centre, London NW1 0NH, United Kingdom
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6
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Rakvin B, Carić D, Kveder M. Enhanced accuracy of the microwave field strength measurement in a CW-EPR by pulsed modulation technique. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 287:123-127. [PMID: 29413325 DOI: 10.1016/j.jmr.2018.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 06/08/2023]
Abstract
The microwave magnetic field strength, B1, in the cavity of a conventional continuous wave electron paramagnetic resonance, CW-EPR, spectrometer was measured by employing modulation sidebands, MS, in the EPR spectrum. MS spectrum in CW-EPR is produced by applying the modulation frequency, ωrf, which exceeds the linewidth, δB, given in frequency units. An amplitude-modulated CW-EPR, AM-CW-EPR, was selected as detection method. Theoretical description of AM-CW-EPR spectrum was modified by adding Bloch-Siegert-like shift obtained by taking into account the cumulative effect of the non-resonant interactions between the driving fields and the spin system. This approach enables to enhance the precision of B1 measurement. In order to increase the sensitivity of the method when saturation effects, due to higher intensity of B1, decrease the resolution of AM-CW-EPR spectrum, detection at the second harmonic of CW-EPR has been employed.
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Affiliation(s)
- B Rakvin
- Ruđer Bošković Institute, Division of Physical Chemistry, Bijenička 54, Zagreb, Croatia.
| | - D Carić
- Ruđer Bošković Institute, Division of Physical Chemistry, Bijenička 54, Zagreb, Croatia
| | - M Kveder
- Ruđer Bošković Institute, Division of Physical Chemistry, Bijenička 54, Zagreb, Croatia
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7
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Ndiaye AL, Delile S, Brunet J, Varenne C, Pauly A. Electrochemical Sensors Based on Screen-Printed Electrodes: The Use of Phthalocyanine Derivatives for Application in VFA Detection. BIOSENSORS-BASEL 2016; 6:bios6030046. [PMID: 27598214 PMCID: PMC5039665 DOI: 10.3390/bios6030046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/04/2016] [Accepted: 08/25/2016] [Indexed: 12/04/2022]
Abstract
Here, we report on the use of electrochemical methods for the detection of volatiles fatty acids (VFAs), namely acetic acid. We used tetra-tert-butyl phthalocyanine (PcH2-tBu) as the sensing material and investigated its electroanalytical properties by means of cyclic voltammetry (CV) and square wave voltammetry (SWV). To realize the electrochemical sensing system, the PcH2-tBu has been dropcast-deposited on carbon (C) orgold (Au)screen-printed electrodes (SPEs) and characterized by cyclic voltammetry and scanning electron microscopy (SEM). The SEM analysis reveals that the PcH2-tBu forms mainly aggregates on the SPEs. The modified electrodes are used for the detection of acetic acid and present a linear current increase when the acetic acid concentration increases. The Cmodified electrode presents a limit of detection (LOD) of 25.77 mM in the range of 100 mM–400 mM, while the Aumodified electrode presents an LOD averaging 40.89 mM in the range of 50 mM–300 mM. When the experiment is realized in a buffered condition, theCmodified electrode presents a lower LOD, which averagesthe 7.76 mM. A pronounced signal decay attributed to an electrode alteration is observed in the case of the gold electrode. This electrode alteration severely affects the coating stability. This alteration is less perceptible in the case of the carbon electrode.
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Affiliation(s)
- Amadou L Ndiaye
- Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France.
- CNRS, UMR 6602, Institut Pascal, Campus Universitaire des Cézeaux, 4 Avenue Blaise Pascal, 63178 Aubiere Cedex, France.
| | - Sébastien Delile
- Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France.
- CNRS, UMR 6602, Institut Pascal, Campus Universitaire des Cézeaux, 4 Avenue Blaise Pascal, 63178 Aubiere Cedex, France.
| | - Jérôme Brunet
- Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France.
- CNRS, UMR 6602, Institut Pascal, Campus Universitaire des Cézeaux, 4 Avenue Blaise Pascal, 63178 Aubiere Cedex, France.
| | - Christelle Varenne
- Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France.
- CNRS, UMR 6602, Institut Pascal, Campus Universitaire des Cézeaux, 4 Avenue Blaise Pascal, 63178 Aubiere Cedex, France.
| | - Alain Pauly
- Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand, France.
- CNRS, UMR 6602, Institut Pascal, Campus Universitaire des Cézeaux, 4 Avenue Blaise Pascal, 63178 Aubiere Cedex, France.
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8
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Miyoshi Y, Yoshikawa H, Awaga K. Crystal-to-crystal transformation in solid-state electrochemical doping of Cl− ions to the nanoporous neutral radical lithium phthalocyanine: revelation of electron–electron correlations in the 1D half-filled system. CrystEngComm 2014. [DOI: 10.1039/c4ce01222d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solid-state electrochemical doping of Cl− ions to nanoporous LiPc crystals induces crystal-to-crystal transformation to LiPc·Clx.
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Affiliation(s)
- Yasuhito Miyoshi
- Department of Chemistry & Research Center for Materials Science
- Nagoya University
- Nagoya 464-8602, Japan
| | - Hirofumi Yoshikawa
- Department of Chemistry & Research Center for Materials Science
- Nagoya University
- Nagoya 464-8602, Japan
| | - Kunio Awaga
- Department of Chemistry & Research Center for Materials Science
- Nagoya University
- Nagoya 464-8602, Japan
- CREST
- Nagoya University
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9
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Apetrei C, Medina-Plaza C, de Saja JA, Rodriguez-Mendez ML. Electrochemical characterization of dilithium phthalocyanine carbonaceous electrodes. J PORPHYR PHTHALOCYA 2013. [DOI: 10.1142/s1088424613500430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Carbonaceous electrodes of dilithium phthalocyanine were prepared using graphite, carbon microspheres and multiwall carbon nanotubes. The electrochemical behavior of the dilithium bisphthalocyanine electrodes was found to be dependent on the nature of the carbonaceous material and on the nature of the electrolytic solution. The electrocatalytic properties of the dilithium phthalocyanine electrodes for oxidation of ascorbic acid were evidenced by the enhancement of the oxidation peak current, (~10 fold compared to the bare carbon electrodes) and the decrease of the oxidation potential at which oxidation of ascorbic acid takes place. The combined use of multiwall carbon nanotubes and dilithium phthalocyanine produces a synergistic effect that improves the electrocatalytic effect towards ascorbic acid.
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Affiliation(s)
- Constantin Apetrei
- Department of Inorganic Chemistry, Escuela de Ingenierías Industriales, University of Valladolid, Paseo del Cauce, 59, 47011 Valladolid, Spain
- Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, "Dunarea de Jos", University of Galati, 47 Domneasca Street, 800008 Galati, Romania
| | - Cristina Medina-Plaza
- Department of Inorganic Chemistry, Escuela de Ingenierías Industriales, University of Valladolid, Paseo del Cauce, 59, 47011 Valladolid, Spain
| | - José Antonio de Saja
- Department of Condensed Matter Physics, Faculty of Sciences, University of Valladolid, 47011 Valladolid, Spain
| | - Maria Luz Rodriguez-Mendez
- Department of Inorganic Chemistry, Escuela de Ingenierías Industriales, University of Valladolid, Paseo del Cauce, 59, 47011 Valladolid, Spain
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10
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Huebner R, Kandaiah S, Jansen M. Non-Planar Lithium-Phthalocyanine in the Double Salt (nBu4N)2[Lipc]PF6. Z Anorg Allg Chem 2012. [DOI: 10.1002/zaac.201200276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Manan NSA, Aldous L, Alias Y, Compton RG, Lagunas MC, Hardacre C. Electrochemistry of Hg(II) Salts in Room-Temperature Ionic Liquids. J Phys Chem B 2011; 115:2574-81. [DOI: 10.1021/jp1120096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ninie S A Manan
- School of Chemistry and Chemical Engineering, The QUILL Centre, Queen's University, Belfast BT9 5AG, UK
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12
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Evaluation of Lithium Naphthalocyanine (LiNc) Microcrystals for Biological EPR Oximetry. OXYGEN TRANSPORT TO TISSUE XXXII 2011; 701:29-36. [DOI: 10.1007/978-1-4419-7756-4_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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13
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Ahmad R, Kuppusamy P. Theory, instrumentation, and applications of electron paramagnetic resonance oximetry. Chem Rev 2010; 110:3212-36. [PMID: 20218670 PMCID: PMC2868962 DOI: 10.1021/cr900396q] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Rizwan Ahmad
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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14
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Takeshita K, Kawaguchi K, Fujii-Aikawa K, Ueno M, Okazaki S, Ono M, Krishna MC, Kuppusamy P, Ozawa T, Ikota N. Heterogeneity of regional redox status and relation of the redox status to oxygenation in a tumor model, evaluated using electron paramagnetic resonance imaging. Cancer Res 2010; 70:4133-40. [PMID: 20442282 DOI: 10.1158/0008-5472.can-09-4369] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It is widely accepted that redox status, along with the partial pressure of oxygen (pO(2)), determines the efficacy of some therapeutic methods applied to treat tumors, including radiation. Redox status, evaluated by the reduction of a nitroxyl probe, was reportedly heterogeneous in a mouse tumor model. However, neither variation of heterogeneity of the redox status among mice nor the relation of the redox status to pO(2) in tumors has been characterized sufficiently. In this study, the regional reduction status in a mouse radiation-induced fibrosarcoma tumor model was evaluated using sequential three-dimensional electron paramagnetic resonance (EPR) imaging after i.v. injection of a tissue-permeable nitroxyl probe, HM-PROXYL. The regional decay of HM-PROXYL signal obeyed first-order kinetics, and the amplitude of the reduction rate and extent of its heterogeneity in a tumor varied among six mice. The tissue pO(2) was measured using EPR oximetry with lithium phthalocyanine (LiPc) microcrystals implanted within the tumor. The location of LiPc was determined with EPR imaging. A sequential image was obtained following the injection of HM-PROXYL, even after LiPc implantation, by choosing an HM-PROXYL signal peak which does not overlap with the signal of LiPc. The relationship between pO(2) and the reduction rate at the region of pO(2) measurement was found to be low (r = 0.357) in 13 tumor-bearing mice, indicating that the extent of oxygenation does not necessarily affect the redox status under air-breathing conditions. The results strongly indicate the necessity of measurements of both redox status and oxygenation in every tumor to characterize tumor physiology.
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Affiliation(s)
- Keizo Takeshita
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan.
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15
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Eteshola E, Pandian RP, Lee SC, Kuppusamy P. Polymer coating of paramagnetic particulates for in vivo oxygen-sensing applications. Biomed Microdevices 2009; 11:379-87. [PMID: 19083100 DOI: 10.1007/s10544-008-9244-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Crystalline lithium phthalocyanine (LiPc) can be used to sense oxygen. To enhance biocompatibility/stability of LiPc, we encapsulated LiPc in Teflon AF (TAF), cellulose acetate (CA), and polyvinyl acetate (PVAc) (TAF, previously used to encapsulate LiPc, was a comparator). We identified water-miscible solvents that don't dissolve LiPc crystals, but are solvents for the polymers, and encapsulated crystals by solvent evaporation. Oxygen sensitivity of films was characterized in vitro and in vivo. Encapsulation did not change LiPc oximetry properties in vitro at anoxic conditions or varying partial pressures of oxygen (pO2). EPR linewidth of encapsulated particles was linear with pO2, responding to pO2 changes quickly and reproducibly for dynamic measurements. Encapsulated LiPc was unaffected by biological oxidoreductants, stable in vivo for four weeks. Oximetry, stability and biocompatibility properties of LiPc films were comparable, but both CA and PVAc films are cheaper, and easier to fabricate and handle than TAF films, making them superior.
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Affiliation(s)
- Edward Eteshola
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
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16
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Inagawa M, Yoshikawa H, Yokoyama T, Awaga K. Electrochemical structural transformation and reversible doping/dedoping of lithium phthalocyanine thin films. Chem Commun (Camb) 2009:3389-91. [DOI: 10.1039/b902903f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Pandian RP, Dolgos M, Marginean C, Woodward PM, Hammel PC, Manoharan PT, Kuppusamy P. Molecular packing and magnetic properties of lithium naphthalocyanine crystals: hollow channels enabling permeability and paramagnetic sensitivity to molecular oxygen. JOURNAL OF MATERIALS CHEMISTRY 2009; 19:4138-4147. [PMID: 19809598 PMCID: PMC2756769 DOI: 10.1039/b901886g] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis, structural framework, magnetic and oxygen-sensing properties of a lithium naphthalocyanine (LiNc) radical probe are presented. LiNc was synthesized in the form of a microcrystalline powder using a chemical method and characterized by electron paramagnetic resonance (EPR) spectroscopy, magnetic susceptibility, powder X-ray diffraction analysis, and mass spectrometry. X-Ray powder diffraction studies revealed a structural framework that possesses long, hollow channels running parallel to the packing direction. The channels measured approximately 5.0 × 5.4 Å(2) in the two-dimensional plane perpendicular to the length of the channel, enabling diffusion of oxygen molecules (2.9 × 3.9 Å(2)) through the channel. The powdered LiNc exhibited a single, sharp EPR line under anoxic conditions, with a peak-to-peak linewidth of 630 mG at room temperature. The linewidth was sensitive to surrounding molecular oxygen, showing a linear increase in pO(2) with an oxygen sensitivity of 31.2 mG per mmHg. The LiNc microcrystals can be further prepared as nano-sized crystals without the loss of its high oxygen-sensing properties. The thermal variation of the magnetic properties of LiNc, such as the EPR linewidth, EPR intensity and magnetic susceptibility revealed the existence of two different temperature regimes of magnetic coupling and hence differing columnar packing, both being one-dimensional antiferromagnetic chains but with differing magnitudes of exchange coupling constants. At a temperature of ∼50 K, LiNc crystals undergo a reversible phase transition. The high degree of oxygen-sensitivity of micro- and nano-sized crystals of LiNc, combined with excellent stability, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy.
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Affiliation(s)
- Ramasamy P. Pandian
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Michelle Dolgos
- Department of Chemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Camelia Marginean
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Patrick M. Woodward
- Department of Chemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - P. Chris Hammel
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | | | - Periannan Kuppusamy
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
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18
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Subramanian S, Krishna MC. DANCING WITH THE ELECTRONS: TIME-DOMAIN AND CW IN VIVO EPR IMAGING. MAGNETIC RESONANCE INSIGHTS 2008; 2:43-74. [PMID: 22025900 DOI: 10.4137/mri.s1131] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The progress in the development of imaging the distribution of unpaired electrons in living systems and the functional and the potential diagnostic dimensions of such an imaging process, using Electron Paramagnetic Resonance Imaging (EPRI), is traced from its origins with emphasis on our own work. The importance of EPR imaging stems from the fact that many paramagnetic probes show oxygen dependent spectral broadening. Assessment of in vivo oxygen concentration is an important factor in radiation oncology in treatment-planning and monitoring treatment-outcome. The emergence of narrow-line trairylmethyl based, bio-compatible spin probes has enabled the development of radiofrequency time-domain EPRI. Spectral information in time-domain EPRI can be achieved by generating a time sequence of T(2)* or T(2) weighted images. Progress in CW imaging has led to the use of rotating gradients, more recently rapid scan with direct detection, and a combination of all the three. Very low field MRI employing Dynamic Nuclear polarization (Overhauser effect) is also employed for monitoring tumor hypoxia, and re-oxygenation in vivo. We have also been working on the co-registration of MRI and time domain EPRI on mouse tumor models at 300 MHz using a specially designed resonator assembly. The mapping of the unpaired electron distribution and unraveling the spectral characteristics by using magnetic resonance in presence of stationary and rotating gradients in indeed 'dancing with the (unpaired) electrons', metaphorically speaking.
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Affiliation(s)
- Sankaran Subramanian
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Presley T, Vedam K, Velayutham M, Zweier JL, Ilangovan G. Activation of Hsp90-eNOS and increased NO generation attenuate respiration of hypoxia-treated endothelial cells. Am J Physiol Cell Physiol 2008; 295:C1281-91. [PMID: 18787079 DOI: 10.1152/ajpcell.00550.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hypoxia induces various adoptive signaling in cells that can cause several physiological changes. In the present work, we have observed that exposure of bovine aortic endothelial cells (BAECs) to extreme hypoxia (1-5% O(2)) attenuates cellular respiration by a mechanism involving heat shock protein 90 (Hsp90) and endothelial nitric oxide (NO) synthase (eNOS), so that the cells are conditioned to consume less oxygen and survive in prolonged hypoxic conditions. BAECs, exposed to 1% O(2), showed a reduced respiration compared with 21% O(2)-maintained cells. Western blot analysis showed an increase in the association of Hsp90-eNOS and enhanced NO generation on hypoxia exposure, whereas there was no significant accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha). The addition of inhibitors of Hsp90, phosphatidylinositol 3-kinase, and NOS significantly alleviated this hypoxia-induced attenuation of respiration. Thus we conclude that hypoxia-induced excess NO and its derivatives such as ONOO(-) cause inhibition of the electron transport chain and attenuate O(2) demand, leading to cell survival at extreme hypoxia. More importantly, such an attenuation is found to be independent of HIF-1alpha, which is otherwise thought to be the key regulator of respiration in hypoxia-exposed cells, through a nonphosphorylative glycolytic pathway. The present mechanistic insight will be helpful to understand the difference in the magnitude of endothelial dysfunction.
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Affiliation(s)
- Tennille Presley
- Rm. 392, Biomedical Research Tower, Ohio State Univ., 420 West 12th Ave., Columbus, OH 43210, USA
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20
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Matsumoto S, Espey MG, Utsumi H, Devasahayam N, Matsumoto KI, Matsumoto A, Hirata H, Wink DA, Kuppusamy P, Subramanian S, Mitchell JB, Krishna MC. Dynamic monitoring of localized tumor oxygenation changes using RF pulsed electron paramagnetic resonance in conscious mice. Magn Reson Med 2008; 59:619-25. [PMID: 18224698 DOI: 10.1002/mrm.21500] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Oxygenation status is a key determinant in both tumor growth and responses to therapeutic interventions. The oxygen partial pressure (pO2) was assessed using a novel pulsed electron paramagnetic resonance (EPR) spectroscopy at 750 MHz. Crystals of lithium phthalocyanine (LiPc) implanted into either squamous cell carcinoma (SCC) tumor or femoral muscle on opposing legs of mice were tested by pulsed EPR. The results showed pO2 of SCC tumor was 2.7 +/- 0.4 mmHg, while in the femoral muscle it was 6.1 +/- 0.9 mmHg. A major advantage of pulsed EPR oximetry over conventional continuous-wave (CW) EPR oximetry is the lack of influence from subject motion, while avoiding artifacts associated with modulation or power saturation. Resonators in pulsed EPR are overcoupled to minimize recovery time. This makes changes in coupling associated with object motion minimal without influencing spectral quality. Consequently, pulsed EPR oximetry enables approximately a temporal resolution of approximately one second in pO2 monitoring in conscious subjects, avoiding significant influence of anesthetics on the physiology being studied. The pO2 in SCC tumor and muscle was found to be higher without anesthesia (3.9 +/- 0.5 mmHg for tumor, 8.8 +/- 1.2 mmHg for muscle). These results support the advantage of pulsed EPR in examining pO2 in conscious animals with LiPc chronically implanted in predetermined regions.
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Affiliation(s)
- Shingo Matsumoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1002, USA
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Nafady A, Bond AM, Bilyk A, Harris AR, Bhatt AI, O'Mullane AP, De Marco R. Tuning the Electrocrystallization Parameters of Semiconducting Co[TCNQ]2-Based Materials To Yield either Single Nanowires or Crystalline Thin Films. J Am Chem Soc 2007; 129:2369-82. [PMID: 17263534 DOI: 10.1021/ja067219j] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrocrystallization of single nanowires and/or crystalline thin films of the semiconducting and magnetic Co[TCNQ]2(H2O)2 (TCNQ=tetracyanoquinodimethane) charge-transfer complex onto glassy carbon, indium tin oxide, or metallic electrodes occurs when TCNQ is reduced in acetonitrile (0.1 M [NBu4][ClO4]) in the presence of hydrated cobalt(II) salts. The morphology of the deposited solid is potential dependent. Other factors influencing the electrocrystallization process include deposition time, concentration, and identity of the Co2+(MeCN) counteranion. Mechanistic details have been elucidated by use of cyclic voltammetry, chronoamperometry, electrochemical quartz crystal microbalance, and galvanostatic methods together with spectroscopic and microscopic techniques. The results provide direct evidence that electrocrystallization takes place through two distinctly different, potential-dependent mechanisms, with progressive nucleation and 3-D growth being controlled by the generation of [TCNQ]*- at the electrode and the diffusion of Co2+(MeCN) from the bulk solution. Images obtained by scanning electron microscopy reveal that electrocrystallization of Co[TCNQ]2(H2O)2 at potentials in the range of 0.1-0 V vs Ag/AgCl, corresponding to the [TCNQ]0/*- diffusion-controlled regime, gives rise to arrays of well-separated, needle-shaped nanowires via the overall reaction 2[TCNQ]*-(MeCN)+Co2+(MeCN)+2H2O right harpoon over left harpoon {Co[TCNQ]2(H2O)2}(s). In this potential region, nucleation and growth occur at randomly separated defect sites on the electrode surface. In contrast, at more negative potentials, a compact film of densely packed, uniformly oriented, hexagonal-shaped nanorods is formed. This is achieved at a substantially increased number of nucleation sites created by direct reduction of a thin film of what is proposed to be cobalt-stabilized {(Co2+)([TCNQ2]*-)2} dimeric anion. Despite the potential-dependent morphology of the electrocrystallized Co[TCNQ]2(H2O)2 and the markedly different nucleation-growth mechanisms, IR, Raman, elemental, and thermogravimetric analyses, together with X-ray diffraction, all confirmed the formation of a highly pure and crystalline phase of Co[TCNQ]2(H2O)2 on the electrode surface. Thus, differences in the electrodeposited material are confined to morphology and not to phase or composition differences. This study highlights the importance of the electrocrystallization approach in constructing and precisely controlling the morphology and stoichiometry of Co[TCNQ]2-based materials.
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Affiliation(s)
- Ayman Nafady
- School of Chemistry, Monash University, P.O. Box 23, Victoria 3800, Australia
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22
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Kharisov BI, Ortiz Méndez U, Garza-Rodríguez LA, Leija Gutiérrez HM, Medina Medina A, Berdonosov SS. Use of various activated forms of elemental nickel and copper for the synthesis of phthalocyanine at low temperature. J COORD CHEM 2007. [DOI: 10.1080/00958970600577635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- B. I. Kharisov
- a Universidad Autónoma de Nuevo León , A.P. 18-F, C.P. 66450, Ciudad Universitaria UANL, San Nicolás de los Garza, N.L., México
- b Institute of Physical Chemistry and Electrochemistry , Moscow State University , Moscow, Russia
| | - U. Ortiz Méndez
- a Universidad Autónoma de Nuevo León , A.P. 18-F, C.P. 66450, Ciudad Universitaria UANL, San Nicolás de los Garza, N.L., México
| | - L. A. Garza-Rodríguez
- a Universidad Autónoma de Nuevo León , A.P. 18-F, C.P. 66450, Ciudad Universitaria UANL, San Nicolás de los Garza, N.L., México
| | - H. M. Leija Gutiérrez
- a Universidad Autónoma de Nuevo León , A.P. 18-F, C.P. 66450, Ciudad Universitaria UANL, San Nicolás de los Garza, N.L., México
| | - A. Medina Medina
- a Universidad Autónoma de Nuevo León , A.P. 18-F, C.P. 66450, Ciudad Universitaria UANL, San Nicolás de los Garza, N.L., México
| | - S. S. Berdonosov
- c Department of Chemistry , Moscow State University , Moscow, Russia
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Presley T, Kuppusamy P, Zweier JL, Ilangovan G. Electron paramagnetic resonance oximetry as a quantitative method to measure cellular respiration: a consideration of oxygen diffusion interference. Biophys J 2006; 91:4623-31. [PMID: 17012319 PMCID: PMC1779914 DOI: 10.1529/biophysj.106.090175] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electron paramagnetic resonance (EPR) oximetry is being widely used to measure the oxygen consumption of cells, mitochondria, and submitochondrial particles. However, further improvement of this technique, in terms of data analysis, is required to use it as a quantitative tool. Here, we present a new approach for quantitative analysis of cellular respiration using EPR oximetry. The course of oxygen consumption by cells in suspension has been observed to have three distinct zones: pO(2)-independent respiration at higher pO(2) ranges, pO(2)-dependent respiration at low pO(2) ranges, and a static equilibrium with no change in pO(2) at very low pO(2) values. The approach here enables one to comprehensively analyze all of the three zones together-where the progression of O(2) diffusion zones around each cell, their overlap within time, and their potential impact on the measured pO(2) data are considered. The obtained results agree with previously established methods such as high-resolution respirometry measurements. Additionally, it is also demonstrated how the diffusion limitations can depend on cell density and consumption rate. In conclusion, the new approach establishes a more accurate and meaningful model to evaluate the EPR oximetry data on cellular respiration to quantify related parameters using EPR oximetry.
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Affiliation(s)
- Tennille Presley
- The Center for Biomedical EPR Spectroscopy and Imaging, Biophysics Program, Department of Internal Medicine, Davis Heart and Lung Research Institute and The Ohio State University, Columbus, OH 43210, USA
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Deng Y, Pandian RP, Ahmad R, Kuppusamy P, Zweier JL. Application of magnetic field over-modulation for improved EPR linewidth measurements using probes with Lorentzian lineshape. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 181:254-61. [PMID: 16759891 PMCID: PMC1839039 DOI: 10.1016/j.jmr.2006.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2005] [Revised: 05/02/2006] [Accepted: 05/15/2006] [Indexed: 05/10/2023]
Abstract
Magnetic field modulation in CW electron paramagnetic resonance (EPR) is used for signal detection. However, it can also distort signal lineshape. In experiments where the linewidth information is of particular importance, small modulation amplitude is usually used to limit the lineshape distortion. The use of small modulation amplitude, however, results in low signal-to-noise ratio and therefore affects the precision of linewidth measurements. Recently, a new spectral simulation model has been developed enabling accurate fitting of modulation-broadened EPR spectra in liquids. Since the use of large modulation amplitude (over-modulation) can significantly enhance the EPR signal, the precision of linewidth measurements is therefore greatly improved. We investigated the over-modulation technique in EPR oximetry experiments using the oxygen-sensing probe lithium octa-n-butoxy-substitued naphthalocyanine (LiNc-BuO). Modulation amplitudes 2-18 times the intrinsic linewidth of the probe were applied to increase the spectral signal-to-noise ratio. The intrinsic linewidth of the probe at different oxygen concentrations was accurately extracted through curve fitting from the enhanced spectra. Thus, we demonstrated that the over-modulation model is also applicable to particulate oxygen-sensing probes such as LiNc-BuO and that the lineshape broadening induced by oxygen is separable from that induced by over-modulation. Therefore, the over-modulation technique can be used to enhance sensitivity and improve linewidth measurements for EPR oximetry with particulate oxygen-sensing probes with Lorentzian lineshape. It should be particularly useful for in vivo oxygen measurements, in which direct linewidth measurements may not be feasible due to inadequate signal-to-noise ratio.
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Affiliation(s)
- Yuanmu Deng
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
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25
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Pandian RP, Kim YI, Woodward PM, Zweier JL, Manoharan PT, Kuppusamy P. The open molecular framework of paramagnetic lithium octabutoxy-naphthalocyanine: implications for the detection of oxygen and nitric oxide using EPR spectroscopy. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b517976a] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Ilangovan G, Bratasz A, Kuppusamy P. Non-invasive measurement of tumor oxygenation using embedded microparticulate EPR spin probe. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2005; 566:67-73. [PMID: 16594136 DOI: 10.1007/0-387-26206-7_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We have developed a novel procedure for in situ monitoring of oxygen concentration in growing tumors by electron paramagnetic resonance (EPR)-based oximetry using embedded paramagnetic particulates. The new approach uses spin probes that are permanently embedded or implanted in the tumor. A particular advantage of this procedure is that it is non-invasive, both in terms of implantation of the probe as well as readouts of oxygen. We implanted a mixture of RIF-1 tumor cells and microparticulates of lithium phthalocyanine (LiPc) in the upper hind leg of C3H mice to grow as solid tumor. This enabled repeated measurements of oxygen concentration from the implanted site (tumor) for more than two weeks during the progression of the tumor. The particulates that were embedded in the tumor were stable and non-toxic to tumor cells. There was no apparent inhibitory effect to cell proliferation or tumor growth rate. The measurements indicated that the PO2 of the tumor decreased exponentially with tumor growth (size) and reached hypoxia (< 4 mm Hg). EPR imaging was used to identify the distribution of the particles in the tumor. The data showed a heterogeneous distribution of the probe particles within the tumor volume. Imaging of oxygen in the growing tumor demonstrated the development of significant hypoxia in the tumor within 4-6 days after inoculation. In summary, the EPR spectroscopy and imaging using embedded spin probe enabled accurate and repeated measurements of PO2 under non-perturbing conditions in growing tumors.
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Kharisov BI, Ortiz Méndez U, Almaraz Garza JL, Almaguer Rodríguez JR. Synthesis of non-substituted phthalocyanines by standard and non-standard techniques. Influence of solvent nature in phthalocyanine preparation at low temperature by UV-treatment of the reaction system. NEW J CHEM 2005. [DOI: 10.1039/b415712p] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Ilangovan G, Zweier JL, Kuppusamy P. Mechanism of oxygen-induced EPR line broadening in lithium phthalocyanine microcrystals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 170:42-48. [PMID: 15324756 DOI: 10.1016/j.jmr.2004.05.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2004] [Revised: 05/17/2004] [Indexed: 05/24/2023]
Abstract
EPR oximetry has been recognized as an important tool for determining oxygen concentration in biological tissues, in vivo. The method relies on the use of oxygen-sensitive paramagnetic probes whose linewidth varies predictably, mostly linear, with oxygen concentration. Lithium phthalocyanine (LiPc) radical has emerged as the probe of choice due to its superior EPR sensitivity, oxygen response, and biocompatibility. However, there are certain limitations in the preparation of this material in a pure and usable form. In our efforts to improve the synthesis of this material for reliable use in oximetry applications, we developed microcrystalline particulates that showed several advantages over other probes. Despite its advantages, the probe shows linear response to pO2 only in the range of 0-70 mmHg, beyond which a saturation behavior is observed. The goal of this study was to understand the mechanism of the interaction of oxygen with LiPc in order to interpret the experimentally observed linewidths. We propose a dual-spin model in which the freely diffusing spins of LiPc are converted to fixed spins by adsorption of molecular oxygen. The proposed mechanism was verified from the effect of oxygenation/deoxygenation processes on the linewidth of LiPc. In summary, we demonstrated that adsorption of oxygen molecules on LiPc contributes to a nonlinear line-broadening effect. This understanding is important for the future design of new EPR oximetry probes.
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Affiliation(s)
- Govindasamy Ilangovan
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, The Ohio State University, 420 West 12th Avenue, Columbus, OH 43210, USA
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29
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Ilangovan G, Liebgott T, Kutala VK, Petryakov S, Zweier JL, Kuppusamy P. EPR oximetry in the beating heart: myocardial oxygen consumption rate as an index of postischemic recovery. Magn Reson Med 2004; 51:835-42. [PMID: 15065258 DOI: 10.1002/mrm.20000] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Oxygen plays a critical role in the pathophysiology of myocardial injury during both ischemia and subsequent reperfusion (I/R). Thus, oxygen concentration is an important variable to measure during I/R. In the present work, electron paramagnetic resonance (EPR)-based oximetry was used to measure the oxygen concentration during a series of I/R episodes and oxygenation levels were correlated with the contractile and hemodynamic functions of the heart. A custom-developed electronically tunable surface coil resonator working at 1.1 GHz was used to determine tissue pO(2) in the beating heart. Microcrystalline particulate of lithium phthalocyanine was used as an EPR oximetry probe. Isolated and perfused rat hearts were subjected to 1 or 3 hr durations of preischemic perfusion, followed by 15-min I/R cycles. In hearts perfused for 3 hr prior to 15-min I/R cycles, the myocardial pO(2) decreased gradually on subsequent reperfusions of three successive I/R cycles. However, in hearts perfused for 1 hr there was almost 100% recovery of myocardial pO(2) in all three I/R cycles. The extent of oxygenation recovered in each reperfusion cycle correlated with the recovery of hemodynamic and contractile function. The results also showed that the oxygen consumption rate of the heart at the end of each I/R episode decreased in direct proportion to the functional recovery. In summary, it was observed that the amount of myocardial oxygen consumption during I/R could provide a reliable index of functional impairment in the heart.
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30
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Hirata H, Kuyama T, Ono M, Shimoyama Y. Nonequivalent spectra of unpaired electrons in field and frequency modulation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 168:252-258. [PMID: 15140435 DOI: 10.1016/j.jmr.2004.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 03/12/2004] [Indexed: 05/24/2023]
Abstract
We report a difference in the spectral lineshapes of continuous-wave (CW) electron paramagnetic resonance (EPR) spectroscopy between field and frequency modulation. This finding addresses the long-standing question of the effect of modulation in EPR absorption. We compared the first-derivative EPR spectra at 1.1 GHz for lithium phthalocyanine crystals, which have a single narrow linewidth in the EPR absorption spectrum, using field and frequency modulation. The experimental findings suggest that unpaired electrons have different behaviors under perturbation due to field and frequency modulation.
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Affiliation(s)
- Hiroshi Hirata
- Department of Electrical Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan.
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31
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Zhang Y, Alonso PR, Martinez-Limia A, Scanlon LG, Balbuena PB. Crystalline Structure and Lithium-Ion Channel Formation in Self-Assembled Di-lithium Phthalocyanine: Theory and Experiments. J Phys Chem B 2004. [DOI: 10.1021/jp037322k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yingchun Zhang
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, and Air Force Research Laboratory, Energy Storage & Thermal Sciences Branch, Wright-Patterson Air Force Base, Ohio 45433
| | - Paula R. Alonso
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, and Air Force Research Laboratory, Energy Storage & Thermal Sciences Branch, Wright-Patterson Air Force Base, Ohio 45433
| | - Alberto Martinez-Limia
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, and Air Force Research Laboratory, Energy Storage & Thermal Sciences Branch, Wright-Patterson Air Force Base, Ohio 45433
| | - Lawrence G. Scanlon
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, and Air Force Research Laboratory, Energy Storage & Thermal Sciences Branch, Wright-Patterson Air Force Base, Ohio 45433
| | - Perla B. Balbuena
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, and Air Force Research Laboratory, Energy Storage & Thermal Sciences Branch, Wright-Patterson Air Force Base, Ohio 45433
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32
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Ilangovan G, Zweier JL, Kuppusamy P. Microximetry: simultaneous determination of oxygen consumption and free radical production using electron paramagnetic resonance spectroscopy. Methods Enzymol 2004; 381:747-62. [PMID: 15063710 DOI: 10.1016/s0076-6879(04)81048-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Govindasamy Ilangovan
- Biomedical EPR Spectroscopy & Imaging Center, The Ohio State University, Columbus, Ohio 43210, USA
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33
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Pandian RP, Parinandi NL, Ilangovan G, Zweier JL, Kuppusamy P. Novel particulate spin probe for targeted determination of oxygen in cells and tissues. Free Radic Biol Med 2003; 35:1138-48. [PMID: 14572616 DOI: 10.1016/s0891-5849(03)00496-9] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The synthesis and characterization of a new lithium octa-n-butoxy-substituted naphthalocyanine radical probe (LiNc-BuO) and its use in the determination of concentration of oxygen (oximetry) by electron paramagnetic resonance (EPR) spectroscopy are reported. The probe is synthesized as a needle-shaped microcrystalline particulate. The particulate shows a single-line EPR spectrum that is highly exchange-narrowed with a line-width of 210 mG. The EPR line-width is sensitive to molecular oxygen showing a linear relationship between the line-width and concentration of oxygen (pO(2)) with a sensitivity of 8.5 mG/mmHg. We studied a variety of physicochemical and biological properties of LiNc-BuO particulates to evaluate the suitability of the probe for in vivo oximetry. The probe is unaffected by biological oxidoreductants, stable in tissues for several months, and can be successfully internalized in cells. We used this probe to monitor changes in concentration of oxygen in the normal muscle and RIF-1 tumor tissue of mice as a function of tumor growth. The data showed a rapid decrease in the tumor pO(2) with increase of tumor volume. Human arterial smooth muscle cells, upon internalization of the LiNc-BuO probe, showed a marked oxygen gradient across the cell membrane. In summary, the newly synthesized octa-n-butoxy derivative of lithium naphthalocyanine has unique properties that are useful for determining oxygen concentration in chemical and biological systems by EPR spectroscopy and also for magnetic tagging of cells.
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Affiliation(s)
- Ramasamy P Pandian
- Center for Biomedical EPR Spectroscopy and Imaging, Department of Internal Medicine, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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34
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Salikhov I, Hirata H, Walczak T, Swartz HM. An improved external loop resonator for in vivo L-band EPR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 164:54-59. [PMID: 12932455 DOI: 10.1016/s1090-7807(03)00175-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An improved external loop resonator (ELR) used for L-band electron paramagnetic resonance (EPR) spectroscopy is reported. This improvement is achieved by shortening the parallel coaxial line. The resonant structure is formed by two single turn coils (10mm in diameter) that are connected to a parallel coaxial line. A resonance frequency of 1197 MHz and a quality factor of 466 were obtained in the absence of biological tissue and were approximately 1130 MHz and approximately 50 with a living animal, respectively. The sensitivity of the new ELR was compared to the previously developed ELR using three types of EPR samples: (1) paramagnetic material with no biological tissue, (2) paramagnetic material in a leg and in the peritoneal cavity of a dead rat, and (3) paramagnetic material in the back of an anesthetized rat. The sensitivity was 1.2-1.6 times greater in the rat and 4.2 times without tissue.
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Affiliation(s)
- Ildar Salikhov
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH 03755, USA
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35
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Ilangovan G, Li H, Zweier JL, Kuppusamy P. Effect of carbogen-breathing on redox status of the RIF-1 tumor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 510:13-7. [PMID: 12580398 DOI: 10.1007/978-1-4615-0205-0_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- Govindasamy Ilangovan
- EPR Center, Division of Cardiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21224, USA
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36
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Kälin M, Gromov I, Schweiger A. The continuous wave electron paramagnetic resonance experiment revisited. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 160:166-182. [PMID: 12615160 DOI: 10.1016/s1090-7807(02)00186-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
When the modulation frequency used in continuous wave electron paramagnetic resonance (cw EPR) spectroscopy exceeds the linewidth, modulation sidebands appear in the spectrum. It is shown theoretically and experimentally that these sidebands are actually multiple photon transitions, sigma(+)+kxpi, where one microwave (mw) sigma(+) photon is absorbed from the mw radiation field and an arbitrary number k of radio frequency (rf) pi photons are absorbed from or emitted to the modulation rf field. Furthermore, it is demonstrated that both the derivative shape of the lines in standard cw EPR spectra and the distortions due to overmodulation are caused by the unresolved sideband pattern of these lines. The single-photon transition does not even give a contribution to the first-harmonic cw EPR signal. Multiple photon transitions are described semiclassically in a toggling frame and their existence is proven using second quantization. With the toggling frame approach and perturbation theory an effective Hamiltonian for an arbitrary sideband transition is derived. Based on the effective Hamiltonians an expression for the steady-state density operator in the singly rotating frame is derived, completely describing all sidebands in all modulation frequency harmonics of the cw EPR signal. The relative intensities of the sidebands are found to depend in a very sensitive way on the actual rf amplitude and the saturation of single sidebands is shown to depend strongly on the effective field amplitude of the multiple photon transitions. By comparison with the analogous solutions for frequency-modulation EPR it is shown that the field-modulation and the frequency-modulation technique are not equivalent. The experimental data fully verify the theoretical predictions with respect to intensities and lineshapes.
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Affiliation(s)
- Moritz Kälin
- Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland.
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Ilangovan G, Pal R, Zweier JL, Kuppusamy P. Electrochemical Preparation and EPR Studies of Lithium Phthalocyanine. 4. Effect of Nitric Oxide. J Phys Chem B 2002. [DOI: 10.1021/jp026360l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Govindasamy Ilangovan
- Biomedical EPR Imaging Center, Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, 420 West 12th Avenue, Columbus, Ohio 43210
| | - Ranjeeta Pal
- Biomedical EPR Imaging Center, Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, 420 West 12th Avenue, Columbus, Ohio 43210
| | - Jay L. Zweier
- Biomedical EPR Imaging Center, Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, 420 West 12th Avenue, Columbus, Ohio 43210
| | - Periannan Kuppusamy
- Biomedical EPR Imaging Center, Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, 420 West 12th Avenue, Columbus, Ohio 43210
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Ilangovan G, Li H, Zweier JL, Krishna MC, Mitchell JB, Kuppusamy P. In vivo measurement of regional oxygenation and imaging of redox status in RIF-1 murine tumor: effect of carbogen-breathing. Magn Reson Med 2002; 48:723-30. [PMID: 12353291 DOI: 10.1002/mrm.10254] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to noninvasively monitor tumor oxygenation and redox status during hyperoxygenation treatment, such as carbogen-breathing, in a murine tumor model using in vivo electron paramagnetic resonance (EPR) spectroscopy and imaging techniques. The study was performed using implanted lithium phthalocyanine (LiPc) microcrystals as the oximetry probe and 3-carbamoylproxyl (3-CP) as the redox probe in RIF-1 tumors implanted in the upper hind leg of C3H mice. Repetitive measurements of pO(2) from the same tumors as a function of tumor growth (8-24 mm in size) showed that the tumors were hypoxic and that the tumor pO(2) values were decreasing with tumor growth. Carbogen-breathing mostly showed an increase in the tumor oxygenation, although there were considerable variations in the magnitude of change among the tumors. The pharmacokinetic studies with 3-CP showed a significant decrease in the overall tumor reduction status in the carbogen-breathing mice. Spatially resolved (imaging) pharmacokinetic data over the tumor volume were obtained to visualize the distribution of the redox status within the tumor. The redox images of the tumor in the air-breathing mice showed significant heterogeneity in the magnitude and spatial distribution of reducing equivalents. On carbogen-breathing the tissue reduction status decreased considerably, with a concomitant decrease in the heterogeneity of distribution of the redox status. The results suggest that 1) carbogen-breathing considerably enhances tissue oxygenation and significantly decreases the redox status in RIF-1 tumor, and 2) changes in the magnitude and distribution of the redox status within the tumor volume during carbogen-breathing are correlated with the increased tissue oxygenation.
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Affiliation(s)
- Govindasamy Ilangovan
- EPR Center, Division of Cardiology, Department of Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
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Ilangovan G, Manivannan A, Li H, Yanagi H, Zweier JL, Kuppusamy P. A naphthalocyanine-based EPR probe for localized measurements of tissue oxygenation. Free Radic Biol Med 2002; 32:139-47. [PMID: 11796202 DOI: 10.1016/s0891-5849(01)00784-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A new electron paramagnetic resonance (EPR) oximetry probe, based on a naphthalocyanine macrocycle, is reported to exhibit high oxygen sensitivity and favorable EPR characteristics for biological applications. The free radical probe, lithium naphthalocyanine (LiNc), is synthesized as fine microcrystalline powder with particle size less than 1 microm and high spin density. It exhibits a single sharp EPR peak, whose width varies linearly with oxygen partial pressure (pO2). The EPR spectrum is nonsaturable at typical microwave power levels (< 25 mW at X-band). These unique characteristics make this probe ideal for measuring oxygen concentration in biological tissues, in vivo. The peak-to-peak width under anoxic conditions is 0.51 G (at X-band), and it increases linearly with increase in oxygen partial pressure and reaches 26.0 G for 100% oxygen (760 mmHg), showing an oxygen sensitivity of 34 mG/mmHg. The probe responds to changes in pO2 quickly and reproducibly, thus enabling dynamic measurements of regional oxygenation in real time. The application of this probe for oximetry is demonstrated in an in vivo biological system. The changes in pO2 were monitored in the leg muscle tissue of a living mouse breathing room air and carbogen (95% oxygen + 5% CO2), alternatively. The mean pO2 measured with this probe in muscle tissues was consistent with values reported previously using other methods. Overall, the probe shows very desirable characteristics for localized measurements of tissue oxygenation.
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Affiliation(s)
- Govindasamy Ilangovan
- The EPR Center, Division of Cardiology, School of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA
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Ilangovan G, Zweier JL, Kuppusamy P. Electrochemical Preparation and EPR Studies of Lithium Phthalocyanine. Part 2: Particle-Size-Dependent Line Broadening by Molecular Oxygen and Its Implications as an Oximetry Probe. J Phys Chem B 2000. [DOI: 10.1021/jp0013863] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Govindasamy Ilangovan
- The EPR Center and Division of Cardiology, Department of Medicine, Johns Hopkins University, School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, Maryland 21224
| | - Jay L. Zweier
- The EPR Center and Division of Cardiology, Department of Medicine, Johns Hopkins University, School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, Maryland 21224
| | - Periannan Kuppusamy
- The EPR Center and Division of Cardiology, Department of Medicine, Johns Hopkins University, School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, Maryland 21224
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