1
|
Gallez B. Contribution of Harold M. Swartz to In Vivo EPR and EPR Dosimetry. RADIATION PROTECTION DOSIMETRY 2016; 172:16-37. [PMID: 27421469 DOI: 10.1093/rpd/ncw157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In 2015, we are celebrating half a century of research in the application of Electron Paramagnetic Resonance (EPR) as a biodosimetry tool to evaluate the dose received by irradiated people. During the EPR Biodose 2015 meeting, a special session was organized to acknowledge the pioneering contribution of Harold M. (Hal) Swartz in the field. The article summarizes his main contribution in physiology and medicine. Four emerging themes have been pursued continuously along his career since its beginning: (1) radiation biology; (2) oxygen and oxidation; (3) measuring physiology in vivo; and (4) application of these measurements in clinical medicine. The common feature among all these different subjects has been the use of magnetic resonance techniques, especially EPR. In this article, you will find an impressionist portrait of Hal Swartz with the description of the 'making of' this pioneer, a time-line perspective on his career with the creation of three National Institutes of Health-funded EPR centers, a topic-oriented perspective on his career with a description of his major contributions to Science, his role as a mentor and his influence on his academic children, his active role as founder of scientific societies and organizer of scientific meetings, and the well-deserved international recognition received so far.
Collapse
Affiliation(s)
- Bernard Gallez
- Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Avenue Mounier 73.08, B-1200, Brussels, Belgium
| |
Collapse
|
2
|
Abstract
EPR (electron paramagnetic resonance) based biological oximetry is a powerful tool that accurately and repeatedly measures tissue oxygen levels. In vivo determination of oxygen in tissues is crucial for the diagnosis and treatment of a number of diseases. Here, we report the first successful fabrication and remarkable properties of nanofiber sensors for EPR-oximetry applications. Lithium octa-n-butoxynaphthalocyanine (LiNc- BuO), an excellent paramagnetic oxygen sensor, was successfully encapsulated in 300-500 nm diameter fibers consisting of a core of polydimethylsiloxane (PDMS) and a shell of polycaprolactone (PCL) by electrospinning. This core-shell nanosensor (LiNc-BuO-PDMS-PCL) shows a linear dependence of linewidth versus oxygen partial pressure (pO2). The nanofiber sensors have response and recovery times of 0.35 s and 0.55 s, respectively, these response and recovery times are ~12 times and ~218 times faster than those previously reported for PDMS-LiNc-BuO chip sensors. This greater responsiveness is likely due to the high porosity and excellent oxygen permeability of the nanofibers. Electrospinning of the structurally flexible PDMS enabled the fabrication of fibers having tailored spin densities. Core-shell encapsulation ensures the non-exposure of embedded LiNc-BuO and mitigates potential biocompatibility concerns. In vitro evaluation of the fiber performed under exposure to cultured cells showed that it is both stable and biocompatible. The unique combination of biocompatibility due to the PCL 'shell,' the excellent oxygen transparency of the PDMS core, and the excellent oxygen-sensing properties of LiNc-BuO makes LiNc-BuO-PDMS-PCL platform promising for long-term oximetry and repetitive oxygen measurements in both biological systems and clinical applications.
Collapse
|
3
|
Frank J, Gündel D, Drescher S, Thews O, Mäder K. Injectable LiNc-BuO loaded microspheres as in vivo EPR oxygen sensors after co-implantation with tumor cells. Free Radic Biol Med 2015; 89:741-9. [PMID: 26459034 DOI: 10.1016/j.freeradbiomed.2015.10.401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/03/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Electron paramagnetic resonance (EPR) oximetry is a technique which allows accurate and repeatable oxygen measurements. We encapsulated a highly oxygen sensitive particulate EPR spin probe into microparticles to improve its dispersibility and, hence, facilitate the administration. These biocompatible, non-toxic microspheres contained 5-10 % (w/w) spin probe and had an oxygen sensitivity of 0.60 ± 0.01 µT/mmHg. To evaluate the performance of the microparticles as oxygen sensors, they were co-implanted with syngeneic tumor cells in 2 different rat strains. Thus, tissue injury was avoided and the microparticles were distributed all over the tumor tissue. Dynamic changes of the intratumoral oxygen partial pressure during inhalation of 8 %, 21 %, or 100 % oxygen were monitored in vivo by EPR spectroscopy and quantified. Values were verified in vivo by invasive fluorometric measurements using Oxylite probes and ex vivo by pimonidazole adduct accumulation. There were no hints that the tumor physiology or tissue oxygenation had been altered by the microparticles. Hence, these microprobes offer great potential as oxygen sensors in preclinical research, not only for EPR spectroscopy but also for EPR imaging. For instance, the assessment of tissue oxygenation during therapeutic interventions might help understanding pathophysiological processes and lead to an individualized treatment planning or the use of formulations with hypoxia triggered release of active agents.
Collapse
Affiliation(s)
- Juliane Frank
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany
| | - Daniel Gündel
- Julius-Bernstein-Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06112 Halle (Saale), Germany
| | - Simon Drescher
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany
| | - Oliver Thews
- Julius-Bernstein-Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06112 Halle (Saale), Germany.
| | - Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany.
| |
Collapse
|
4
|
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
| | | |
Collapse
|
5
|
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.
Collapse
Affiliation(s)
- Edward Eteshola
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
| | | | | | | |
Collapse
|
6
|
Mik EG, Donkersloot C, Raat NJH, Ince C. Excitation Pulse Deconvolution in Luminescence Lifetime Analysis for Oxygen Measurements In Vivo¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0760012epdill2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
7
|
Dinguizli M, Jeumont S, Beghein N, He J, Walczak T, Lesniewski PN, Hou H, Grinberg OY, Sucheta A, Swartz HM, Gallez B. Development and evaluation of biocompatible films of polytetrafluoroethylene polymers holding lithium phthalocyanine crystals for their use in EPR oximetry. Biosens Bioelectron 2006; 21:1015-22. [PMID: 16368480 DOI: 10.1016/j.bios.2005.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 03/18/2005] [Accepted: 03/18/2005] [Indexed: 11/17/2022]
Abstract
Electron paramagnetic resonance (EPR) oximetry is a powerful technology that allows the monitoring of oxygenation in tissues. The measurement of tissue oxygenation can be achieved using lithium phthalocyanine (LiPc) crystals as oxygen reporters. In order to have biocompatibility for the sensing system and to assure long-term stability in the responsiveness of the system, we developed films of Teflon AF 2400 with embedded LiPc crystals. These systems can be used as retrievable inserts or parts of an implantable resonator or catheter. Atomic force microscopy studies revealed that the surface of the films was regular and planar. The response to oxygen of the sensor (EPR linewidth as a function of pO(2)) remained unchanged after implantation in mice, and was not affected by sterilization or irradiation. The use of resonators, holding LiPc embedded in Teflon AF 2400, implanted in the gastrocnemius muscle of rabbits allowed the monitoring of oxygen during several weeks. Several assays also demonstrated the biocompatibility of the system: (1) no hemolytic effect was noted; (2) no toxicity was found using the systemic injection test of extracts; (3) histological analysis in rabbit muscle in which the films were implanted for 1 week or 3 months was similar to standard polyethylene biocompatible devices. These advanced oxygen sensors are promising tools for future pre-clinical and clinical developments of EPR oximetry. These developments can be applied for other applications of biosensors where there is a need for oxygen permeable membranes.
Collapse
Affiliation(s)
- M Dinguizli
- Biomedical Magnetic Resonance Unit, Laboratory of Medicinal Chemistry and Radiopharmacy, Université Catholique de Louvain, Brussels, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Petelin M, Pavlica Z, Bizimoska S, Sentjurc M. In vivo study of different ointments for drug delivery into oral mucosa by EPR oximetry. Int J Pharm 2004; 270:83-91. [PMID: 14726125 DOI: 10.1016/j.ijpharm.2003.10.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of the present study was to determine the rate of transport and long-term effect of a drug applied to the oral mucosa in different ointments. Three ointments with bioadhesive properties: Orabase, Carbopol 935P, and polymethyl methacrylate (PMM) and the ointment Miglyol without such properties were used. Benzyl nicotinate (BN) was used as an active ingredient that causes hyperemia. The kinetics of drug action was measured by electron paramagnetic resonance (EPR) oximetry in vivo using the paramagnetic probe (Lithium phthalocyanine) implanted beneath the epithelium of the buccal mucosa in rats. EPR spectra line-width was proportional to local changes of partial pressure of oxygen (pO(2)) in tissue and was monitored for 90 min after the application of ointments mixed with BN. The greatest increase in pO(2) and the highest efficiency of drug action was observed after the application of 2% BN in PMM (P<0.01). Additionally in PMM the drug effect increased linearly with BN concentration up to 3%, at higher concentrations (3.5 and 4% BN) no further effect was observed. The results demonstrated that the greatest and the longest effect caused by a hyperemic drug in PMM. By increasing the concentration of the drug in PMM higher pO(2) in the oral mucosa can be established but only until the saturation is reached.
Collapse
Affiliation(s)
- Milan Petelin
- Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, Ljubljana 1000, Slovenia.
| | | | | | | |
Collapse
|
9
|
Lan M, Beghein N, Charlier N, Gallez B. Carbon blacks as EPR sensors for localized measurements of tissue oxygenation. Magn Reson Med 2004; 51:1272-8. [PMID: 15170849 DOI: 10.1002/mrm.20077] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
New electron paramagnetic resonance (EPR) oximetry probes were identified in the class of carbon black materials. These compounds exhibit very high oxygen sensitivity and favorable EPR characteristics for biological applications. At low pO(2), the linewidth is particularly sensitive to changes in oxygen tension (sensitivity of 750 mG/mmHg). The application of the probes for oximetry was demonstrated in vivo: the pO(2) was measured in muscle in which the blood flow was temporarily restricted as well as in tumor-bearing mice during a carbogen breathing challenge. The responsiveness to pO(2) was stable in muscle for at least 3 months. No toxicity was observed using these materials in cellular experiments and in histological studies performed 2, 7, and 28 days after implantation. In view of their EPR characteristics (high sensitivity) as well as the well-characterized production procedure that make them available on a large scale, these probes can be considered as very promising tools for future developments in EPR oximetry.
Collapse
Affiliation(s)
- Minbo Lan
- Laboratory of Medicinal Chemistry and Radiopharmacy, Université Catholique de Louvain, Brussels, Belgium
| | | | | | | |
Collapse
|
10
|
Affiliation(s)
- Dawen Zhao
- Department of The University of Texas Southwestern Medicial Center at Dallas, 75390, USA
| | | | | |
Collapse
|
11
|
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.
Collapse
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
| | | | | | | | | |
Collapse
|
12
|
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.
Collapse
Affiliation(s)
- Ildar Salikhov
- EPR Center for the Study of Viable Systems, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, NH 03755, USA
| | | | | | | |
Collapse
|
13
|
Mik EG, Donkersloot C, Raat NJH, Ince C. Excitation pulse deconvolution in luminescence lifetime analysis for oxygen measurements in vivo. Photochem Photobiol 2002; 76:12-21. [PMID: 12126302 DOI: 10.1562/0031-8655(2002)076<0012:epdill>2.0.co;2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Oxygen-dependent quenching of phosphorescence has been proven to be a valuable tool for the measurement of oxygen concentrations both in vitro and in vivo. For biological measurements the relatively long lifetimes of phosphorescence have promoted time-domain-based devices using xenon arc flashlamps as the most common excitation light source. The resulting complex form of the excitation pulse leads to complications in the analysis of phosphorescence lifetimes and ultimately to errors in the recovered pO2 values. Although the problem has been recognized, the consequences on in vivo phosphorescence lifetime measurements have been neglected so far. In this study, the consequences of finite excitation flash duration are analyzed using computer simulations, and a method for the recovery of phosphorescence decay times from complex photometric signals is presented. The analysis provides an explanation as to why different calibration constants are reported in the literature and presents a unified explanation whereby calibration constants are not solely a property of the dye but also of the measuring device. It is concluded that complex excitation pulse patterns without appropriate analysis methods lead to device-specific calibration constants and nonlinearity and can be a potent source of errors when applied in vivo. The method of analysis presented in this article allows reliable phosphorescence lifetime measurements to be made for oxygen pressure measurements and can easily be applied to existing phosphorimeters.
Collapse
Affiliation(s)
- Egbert G Mik
- Department of Physiology, Academic Medical Center, University of Amsterdam, The Netherlands
| | | | | | | |
Collapse
|