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Low-Energy Electron Generation for Biomolecular Damage Inquiry: Instrumentation and Methods. BIOPHYSICA 2022. [DOI: 10.3390/biophysica2040041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Technological advancement has produced a variety of instruments and methods to generate electron beams that have greatly assisted in the extensive theoretical and experimental efforts devoted to investigating the effect of secondary electrons with energies approximately less than 100 eV, which are referred as low-energy electrons (LEEs). In the past two decades, LEE studies have focused on biomolecular systems, which mainly consist of DNA and proteins and their constituents as primary cellular targets of ionizing radiation. These studies have revealed that compared to other reactive species produced by high-energy radiation, LEEs have distinctive pathways and considerable efficiency in inducing lethal DNA lesions. The present work aims to briefly discuss the current state of LEE production technology and to motivate further studies and improvements of LEE generation techniques in relation to biological electron-driven processes associated with such medical applications as radiation therapy and cancer treatment.
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Chen X, Karmaker N, Cloutier P, Bass AD, Zheng Y, Sanche L. Low-Energy Electron Damage to Plasmid DNA in Thin Films: Dependence on Substrates, Surface Density, Charging, Environment, and Uniformity. J Phys Chem B 2022; 126:5443-5457. [PMID: 35834372 DOI: 10.1021/acs.jpcb.2c03664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interaction of low-energy electrons (LEEs) with DNA plays a significant role in the mechanisms leading to biological damage induced by ionizing radiation, particularly in radiotherapy, and its sensitization by chemotherapeutic drugs and nanoparticles. Plasmids constitute the form of DNA found in mitochondria and appear as a suitable model of genomic DNA. In a search for the best LEE targets, damage was induced to plasmids, in thin films in vacuum, by 6, 10, and 100 eV electrons under single collision conditions. The yields of single- and double-strand breaks, other cluster damage, isolated base lesions, and crosslinks were measured by electrophoresis and enzyme treatment. The films were deposited on oriented graphite or polycrystalline tantalum, with or without DNA autoassembly via diaminopropane (Dap) intercalation. Yields were correlated with the influence of vacuum, film uniformity, surface density, substrates, and the DNA environment. Aided by surface potential measurements and scanning electron microscopy and atomic force microscopy images, the lyophilized Dap-DNA films were found to be the most practical high-quality targets. These studies pave the way to the fabrication of LEE target-films composed of plasmids intercalated with biomolecules that could mimic the cellular environment; for example, as a first step, by replacing Dap with an amino acid.
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Affiliation(s)
- Xingju Chen
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P. R. China
| | - Nanda Karmaker
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Pierre Cloutier
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Andrew D Bass
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P. R. China.,Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Léon Sanche
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
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3
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Wang F, Li DJ, Li XJ, Cui WZ, Hu TC, Cao M. Modelling energy deposition in polymethyl methacrylate with low-energy electron irradiation. Micron 2022; 156:103232. [DOI: 10.1016/j.micron.2022.103232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 02/24/2022] [Accepted: 02/24/2022] [Indexed: 11/24/2022]
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4
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Liu W, Tan Z, Zhang L, Champion C. Investigation on the correlation between energy deposition and clustered DNA damage induced by low-energy electrons. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2018; 57:179-187. [PMID: 29335772 DOI: 10.1007/s00411-018-0730-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 01/10/2018] [Indexed: 06/07/2023]
Abstract
This study presents the correlation between energy deposition and clustered DNA damage, based on a Monte Carlo simulation of the spectrum of direct DNA damage induced by low-energy electrons including the dissociative electron attachment. Clustered DNA damage is classified as simple and complex in terms of the combination of single-strand breaks (SSBs) or double-strand breaks (DSBs) and adjacent base damage (BD). The results show that the energy depositions associated with about 90% of total clustered DNA damage are below 150 eV. The simple clustered DNA damage, which is constituted of the combination of SSBs and adjacent BD, is dominant, accounting for 90% of all clustered DNA damage, and the spectra of the energy depositions correlating with them are similar for different primary energies. One type of simple clustered DNA damage is the combination of a SSB and 1-5 BD, which is denoted as SSB + BD. The average contribution of SSB + BD to total simple clustered DNA damage reaches up to about 84% for the considered primary energies. In all forms of SSB + BD, the SSB + BD including only one base damage is dominant (above 80%). In addition, for the considered primary energies, there is no obvious difference between the average energy depositions for a fixed complexity of SSB + BD determined by the number of base damage, but average energy depositions increase with the complexity of SSB + BD. In the complex clustered DNA damage constituted by the combination of DSBs and BD around them, a relatively simple type is a DSB combining adjacent BD, marked as DSB + BD, and it is of substantial contribution (on average up to about 82%). The spectrum of DSB + BD is given mainly by the DSB in combination with different numbers of base damage, from 1 to 5. For the considered primary energies, the DSB combined with only one base damage contributes about 83% of total DSB + BD, and the average energy deposition is about 106 eV. However, the energy deposition increases with the complexity of clustered DNA damage, and therefore, the clustered DNA damage with high complexity still needs to be considered in the study of radiation biological effects, in spite of their small contributions to all clustered DNA damage.
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Affiliation(s)
- Wei Liu
- School of Electrical Engineering, Shandong University, Jinan, 250061, Shandong, People's Republic of China
- School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan, 250357, People's Republic of China
| | - Zhenyu Tan
- School of Electrical Engineering, Shandong University, Jinan, 250061, Shandong, People's Republic of China.
| | - Liming Zhang
- Electric Power Research Institute of Tianjin Electric Power Corporation, Tianjin, 300384, People's Republic of China
| | - Christophe Champion
- Centre d'Etudes Nucléaires de Bordeaux Gradignan, Université de Bordeaux, CNRS/IN2P3, BP 120, 33175, Gradignan, France
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Rackwitz J, Bald I. Low-Energy Electron-Induced Strand Breaks in Telomere-Derived DNA Sequences-Influence of DNA Sequence and Topology. Chemistry 2018; 24:4680-4688. [PMID: 29359819 DOI: 10.1002/chem.201705889] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Indexed: 12/19/2022]
Abstract
During cancer radiation therapy high-energy radiation is used to reduce tumour tissue. The irradiation produces a shower of secondary low-energy (<20 eV) electrons, which are able to damage DNA very efficiently by dissociative electron attachment. Recently, it was suggested that low-energy electron-induced DNA strand breaks strongly depend on the specific DNA sequence with a high sensitivity of G-rich sequences. Here, we use DNA origami platforms to expose G-rich telomere sequences to low-energy (8.8 eV) electrons to determine absolute cross sections for strand breakage and to study the influence of sequence modifications and topology of telomeric DNA on the strand breakage. We find that the telomeric DNA 5'-(TTA GGG)2 is more sensitive to low-energy electrons than an intermixed sequence 5'-(TGT GTG A)2 confirming the unique electronic properties resulting from G-stacking. With increasing length of the oligonucleotide (i.e., going from 5'-(GGG ATT)2 to 5'-(GGG ATT)4 ), both the variety of topology and the electron-induced strand break cross sections increase. Addition of K+ ions decreases the strand break cross section for all sequences that are able to fold G-quadruplexes or G-intermediates, whereas the strand break cross section for the intermixed sequence remains unchanged. These results indicate that telomeric DNA is rather sensitive towards low-energy electron-induced strand breakage suggesting significant telomere shortening that can also occur during cancer radiation therapy.
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Affiliation(s)
- Jenny Rackwitz
- Institute of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Ilko Bald
- Institute of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany.,Department 1-Analytical Chemistry and Reference Materials, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter Str. 11, 12489, Berlin, Germany
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6
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Ribar A, Huber SE, Smiałek MA, Tanzer K, Neustetter M, Schürmann R, Bald I, Denifl S. Hydroperoxyl radical and formic acid formation from common DNA stabilizers upon low energy electron attachment. Phys Chem Chem Phys 2018; 20:5578-5585. [PMID: 29410988 DOI: 10.1039/c7cp07697e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) and ethylenediaminetetraacetic acid (EDTA) are key components of biological buffers and are frequently used as DNA stabilizers in irradiation studies. Such surface or liquid phase studies are done with the aim to understand the fundamental mechanisms of DNA radiation damage and to improve cancer radiotherapy. When ionizing radiation is used, abundant secondary electrons are formed during the irradiation process, which are able to attach to the molecular compounds present on the surface. In the present study we experimentally investigate low energy electron attachment to TRIS and methyliminodiacetic acid (MIDA), an analogue of EDTA, supported by quantum chemical calculations. The most prominent dissociation channel for TRIS is through hydroperoxyl radical formation, whereas the dissociation of MIDA results in the formation of formic and acetic acid. These compounds are well-known to cause DNA modifications, like strand breaks. The present results indicate that buffer compounds may not have an exclusive protecting effect on DNA as suggested previously.
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Affiliation(s)
- Anita Ribar
- Institute for Ion Physics and Applied Physics and Center of Molecular Biosciences Innsbruck, Leopold Franzens University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria.
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7
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Schürmann R, Tsering T, Tanzer K, Denifl S, Kumar SVK, Bald I. Resonant Formation of Strand Breaks in Sensitized Oligonucleotides Induced by Low-Energy Electrons (0.5-9 eV). Angew Chem Int Ed Engl 2017; 56:10952-10955. [PMID: 28670830 DOI: 10.1002/anie.201705504] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 12/20/2022]
Abstract
Halogenated nucleobases are used as radiosensitizers in cancer radiation therapy, enhancing the reactivity of DNA to secondary low-energy electrons (LEEs). LEEs induce DNA strand breaks at specific energies (resonances) by dissociative electron attachment (DEA). Although halogenated nucleobases show intense DEA resonances at various electron energies in the gas phase, it is inherently difficult to investigate the influence of halogenated nucleobases on the actual DNA strand breakage over the broad range of electron energies at which DEA can take place (<12 eV). By using DNA origami nanostructures, we determined the energy dependence of the strand break cross-section for oligonucleotides modified with 8-bromoadenine (8Br A). These results were evaluated against DEA measurements with isolated 8Br A in the gas phase. Contrary to expectations, the major contribution to strand breaks is from resonances at around 7 eV while resonances at very low energy (<2 eV) have little influence on strand breaks.
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Affiliation(s)
- Robin Schürmann
- Department of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam-Golm, Germany.,Department 1-Analytical Chemistry and Reference Materials, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter Strasse 11, 12489, Berlin, Germany
| | - Thupten Tsering
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba Mumbai, 400 005, India
| | - Katrin Tanzer
- Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, A-6020, Innsbruck, Austria
| | - Stephan Denifl
- Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, A-6020, Innsbruck, Austria
| | - S V K Kumar
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba Mumbai, 400 005, India
| | - Ilko Bald
- Department of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam-Golm, Germany.,Department 1-Analytical Chemistry and Reference Materials, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter Strasse 11, 12489, Berlin, Germany
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8
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Schürmann R, Tsering T, Tanzer K, Denifl S, Kumar SVK, Bald I. Resonante Bildung von Strangbrüchen in sensibilisierten Oligonukleotiden induziert durch niederenergetische Elektronen (0.5-9.0 eV). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201705504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Robin Schürmann
- Institut für Chemie - Physikalische Chemie; Universität Potsdam; Karl-Liebknecht-Straße 24-25 14476 Potsdam-Golm Deutschland
- Abteilung 1 - Analytische Chemie und Referenzmaterialien; Bundesanstalt für Materialforschung und -prüfung; Richard-Willstätter Str. 11 12489 Berlin Deutschland
| | - Thupten Tsering
- Tata Institute of Fundamental Research; Homi Bhabha Road Colaba Mumbai 400 005 Indien
| | - Katrin Tanzer
- Institut für Ionenphysik und Angewandte Physik; Universität Innsbruck; Technikerstraße 25 A-6020 Innsbruck Österreich
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik; Universität Innsbruck; Technikerstraße 25 A-6020 Innsbruck Österreich
| | - S. V. K. Kumar
- Tata Institute of Fundamental Research; Homi Bhabha Road Colaba Mumbai 400 005 Indien
| | - Ilko Bald
- Institut für Chemie - Physikalische Chemie; Universität Potsdam; Karl-Liebknecht-Straße 24-25 14476 Potsdam-Golm Deutschland
- Abteilung 1 - Analytische Chemie und Referenzmaterialien; Bundesanstalt für Materialforschung und -prüfung; Richard-Willstätter Str. 11 12489 Berlin Deutschland
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9
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Rackwitz J, Kopyra J, Dąbkowska I, Ebel K, Ranković ML, Milosavljević AR, Bald I. Sensitizing DNA Towards Low-Energy Electrons with 2-Fluoroadenine. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603464] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jenny Rackwitz
- Institute of Chemistry-Physical Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
| | - Janina Kopyra
- Faculty of Sciences; Siedlce University; 3 Maja 54 08-110 Siedlce Poland
| | - Iwona Dąbkowska
- Department of Chemistry; University of Gdańsk; 80-952 Gdańsk Poland
| | - Kenny Ebel
- Institute of Chemistry-Physical Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
| | - MiloŠ Lj. Ranković
- Institute of Physics Belgrade; University of Belgrade; Pregrevica 118 11080 Belgrade Serbia
| | - Aleksandar R. Milosavljević
- Institute of Physics Belgrade; University of Belgrade; Pregrevica 118 11080 Belgrade Serbia
- SOLEIL, l'Orme des Merisiers, St. Aubin, BP48, 91192; Gif sur Yvette Cedex France
| | - Ilko Bald
- Institute of Chemistry-Physical Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
- Department 1-Analytical Chemistry and Reference Materials; BAM Federal Institute for Materials Research and Testing; Richard-Willstätter Str. 11 12489 Berlin Germany
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10
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Rackwitz J, Kopyra J, Dąbkowska I, Ebel K, Ranković ML, Milosavljević AR, Bald I. Sensitizing DNA Towards Low-Energy Electrons with 2-Fluoroadenine. Angew Chem Int Ed Engl 2016; 55:10248-52. [PMID: 27481662 DOI: 10.1002/anie.201603464] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/16/2016] [Indexed: 11/09/2022]
Abstract
2-Fluoroadenine ((2F) A) is a therapeutic agent, which is suggested for application in cancer radiotherapy. The molecular mechanism of DNA radiation damage can be ascribed to a significant extent to the action of low-energy (<20 eV) electrons (LEEs), which damage DNA by dissociative electron attachment. LEE induced reactions in (2F) A are characterized both isolated in the gas phase and in the condensed phase when it is incorporated into DNA. Information about negative ion resonances and anion-mediated fragmentation reactions is combined with an absolute quantification of DNA strand breaks in (2F) A-containing oligonucleotides upon irradiation with LEEs. The incorporation of (2F) A into DNA results in an enhanced strand breakage. The strand-break cross sections are clearly energy dependent, whereas the strand-break enhancements by (2F) A at 5.5, 10, and 15 eV are very similar. Thus, (2F) A can be considered an effective radiosensitizer operative at a wide range of electron energies.
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Affiliation(s)
- Jenny Rackwitz
- Institute of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Janina Kopyra
- Faculty of Sciences, Siedlce University, 3 Maja 54, 08-110, Siedlce, Poland
| | - Iwona Dąbkowska
- Department of Chemistry, University of Gdańsk, 80-952, Gdańsk, Poland
| | - Kenny Ebel
- Institute of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - MiloŠ Lj Ranković
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia
| | - Aleksandar R Milosavljević
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080, Belgrade, Serbia.,SOLEIL, l'Orme des Merisiers, St. Aubin, BP48, 91192, Gif sur Yvette Cedex, France
| | - Ilko Bald
- Institute of Chemistry-Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany. .,Department 1-Analytical Chemistry and Reference Materials, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter Str. 11, 12489, Berlin, Germany.
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11
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Kumar SVK, Tare ST, Upalekar YV, Tsering T. Dose controlled low energy electron irradiator for biomolecular films. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:034302. [PMID: 27036792 DOI: 10.1063/1.4944812] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have developed a multi target, Low Energy Electron (LEE), precise dose controlled irradiator for biomolecular films. Up to seven samples can be irradiated one after another at any preset electron energy and dose under UHV conditions without venting the chamber. In addition, one more sample goes through all the steps except irradiation, which can be used as control for comparison with the irradiated samples. All the samples are protected against stray electron irradiation by biasing them at -20 V during the entire period, except during irradiation. Ethernet based communication electronics hardware, LEE beam control electronics and computer interface were developed in house. The user Graphical User Interface to control the irradiation and dose measurement was developed using National Instruments Lab Windows CVI. The working and reliability of the dose controlled irradiator has been fully tested over the electron energy range of 0.5 to 500 eV by studying LEE induced single strand breaks to ΦX174 RF1 dsDNA.
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Affiliation(s)
- S V K Kumar
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Satej T Tare
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Yogesh V Upalekar
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Thupten Tsering
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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12
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Alizadeh E, Orlando TM, Sanche L. Biomolecular damage induced by ionizing radiation: the direct and indirect effects of low-energy electrons on DNA. Annu Rev Phys Chem 2015; 66:379-98. [PMID: 25580626 DOI: 10.1146/annurev-physchem-040513-103605] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many experimental and theoretical advances have recently allowed the study of direct and indirect effects of low-energy electrons (LEEs) on DNA damage. In an effort to explain how LEEs damage the human genome, researchers have focused efforts on LEE interactions with bacterial plasmids, DNA bases, sugar analogs, phosphate groups, and longer DNA moieties. Here, we summarize the current understanding of the fundamental mechanisms involved in LEE-induced damage of DNA and complex biomolecule films. Results obtained by several laboratories on films prepared and analyzed by different methods and irradiated with different electron-beam current densities and fluencies are presented. Despite varied conditions (e.g., film thicknesses and morphologies, intrinsic water content, substrate interactions, and extrinsic atmospheric compositions), comparisons show a striking resemblance in the types of damage produced and their yield functions. The potential of controlling this damage using molecular and nanoparticle targets with high LEE yields in targeted radiation-based cancer therapies is also discussed.
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Affiliation(s)
- Elahe Alizadeh
- Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, J1H 5N4 Sherbrooke, Canada
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Bao Q, Chen Y, Zheng Y, Sanche L. Cisplatin Radiosensitization of DNA Irradiated with 2-20 eV Electrons: Role of Transient Anions. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2014; 118:15516-15524. [PMID: 26793285 PMCID: PMC4716812 DOI: 10.1021/jp503706h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Platinum chemotherapeutic agents, such as cisplatin (cis-diamminedichloroplatinum(II)), can act as radiosensitizers when bound covalently to nuclear DNA in cancer cells. This radiosensitization is largely due to an increase in DNA damage induced by low-energy secondary electrons, produced in large quantities by high-energy radiation. We report the yields of single- and double-strand breaks (SSB and DSB) and interduplex cross-links (CL) induced by electrons of 1.6-19.6 eV (i.e., the yield functions) incident on 5 monolayer (ML) films of cisplatin-DNA complexes. These yield functions are compared with those previously recorded with 5 ML films of unmodified plasmid DNA. Binding of five cisplatin molecules to plasmid DNA (3197 base pairs) enhances SSB, DSB, and CL by factors varying, from 1.2 to 2.8, 1.4 to 3.5, and 1.2 to 2.7, respectively, depending on electron energy. All yield functions exhibit structures around 5 and 10 eV that can be attributed to enhancement of bond scission, via the initial formation of core-excited resonances associated with π → π* transitions of the bases. This increase in damage is interpreted as arising from a modification of the parameters of the corresponding transient anions already present in nonmodified DNA, particularly those influencing molecular dissociation. Two additional resonances, specific to cisplatin-modified DNA, are formed at 13.6 and 17.6 eV in the yield function of SSB. Furthermore, cisplatin binding causes the induction of DSB by electrons of 1.6-3.6 eV, i.e., in an energy region where a DSB cannot be produced by a single electron in pure DNA. Breaking two bonds with a subexcitation-energy electron is tentatively explained by a charge delocalization mechanism, where a single electron occupies simultaneously two σ* bonds linking the Pt atom to guanine bases on opposite strands.
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Affiliation(s)
- Qianhong Bao
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China
| | - Yunfeng Chen
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China
| | - Yi Zheng
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China
| | - Léon Sanche
- Group in the Radiation Sciences, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
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14
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Luo X, Zheng Y, Sanche L. DNA strand breaks and crosslinks induced by transient anions in the range 2-20 eV. J Chem Phys 2014; 140:155101. [PMID: 26792947 PMCID: PMC4716823 DOI: 10.1063/1.4870519] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The energy dependence of the yields of single and double strand breaks (SSB and DSB) and crosslinks induced by electron impact on plasmid DNA films is measured in the 2-20 eV range. The yield functions exhibit two strong maxima, which are interpreted to result from the formation of core-excited resonances (i.e., transient anions) of the bases, and their decay into the autoionization channel, resulting in π → π* electronic transitions of the bases followed by electron transfer to the C-O σ* bond in the phosphate group. Occupancy of the σ* orbital ruptures the C-O bond of the backbone via dissociative electron attachment, producing a SSB. From a comparison of our results with those of other works, including theoretical calculations and electron-energy-loss spectra of the bases, the 4.6 eV peak in the SSB yield function is attributed to the resonance decay into the lowest electronically excited states of the bases; in particular, those resulting from the transitions 13A'(π2 → π3*) and 13A″(n2 → π3*) of thymine and 13A'(π → π*) of cytosine. The strongest peak at 9.6 eV in the SSB yield function is also associated with electron captured by excited states of the bases, resulting mostly from a multitude of higher-energy π → π* transitions. The DSB yield function exhibits strong maxima at 6.1 and 9.6 eV. The peak at 9.6 eV is probably related to the same resonance manifold as that leading to SSB, but the other at 6.1 eV may be more restricted to decay into the electronic state 13A' (π → π*) of cytosine via autoionization. The yield function of crosslinks is dominated by a broad peak extending over the 3.6-11.6 eV range with a sharper one at 17.6 eV. The different line shape of the latter function, compared to that of SSB and DSB, appears to be due to the formation of reactive radical sites in the initial supercoiled configuration of the plasmid, which react with the circular form (i.e., DNA with a SSB) to produce a crosslink.
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Affiliation(s)
- Xinglan Luo
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, People’s Republic of China
| | - Yi Zheng
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, People’s Republic of China
| | - Léon Sanche
- Group in the Radiation Sciences, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
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15
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Bhaskaran R, Sarma M. Effect of quantum tunneling on single strand breaks in a modeled gas phase cytidine nucleotide induced by low energy electron: a theoretical approach. J Chem Phys 2014; 139:045103. [PMID: 23902028 DOI: 10.1063/1.4815975] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Effect of quantum mechanical tunneling on single strand breaks induced by low energy electron (LEE) has been investigated in a modeled gas phase system, 2'-deoxycytidine-3'-monophosphate (3'-dCMPH). The potential energy curves for the sugar-phosphate C-O (3' C-O) bond cleavage have been generated using second order Møller-Plesset perturbation theory at the 6-31+G(d) accuracy level. Results from the electronic structure theory calculations in conjunction with our time dependent calculations for the 3' C-O bond rupture in 3'-dCMPH using local complex potential based time dependent wave packet approach show significant quantum tunneling of the 3' C-O bond from the bound vibrational states above 1 eV of the anionic potential energy curve. A comparison of the fragmentation profile with that of our earlier gas phase investigations based on Hartree-Fock and density functional theory--Becke, 3-parameter, Lee-Yang-Parr methods with 6-31+G(d) basis set is also provided. Further, inspection of the singly occupied molecular orbitals generated at different 3' C-O bond lengths clearly indicates the electron transfer from the low lying base-π(∗) shape resonance state to the phosphate P = O π(∗) orbital of the DNA backbone during the strand breaks. The decisive step during LEE induced strand breaks follows via "charge induced dissociation" (CID) for the metastable anion formed below 1 eV, whereas quantum mechanical tunnel-ing is out-weighted the CID mechanism for the LEE above 1 eV.
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Affiliation(s)
- Renjith Bhaskaran
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781 039, India
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16
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Boulanouar O, Fromm M, Mavon C, Cloutier P, Sanche L. Dissociative electron attachment to DNA-diamine thin films: impact of the DNA close environment on the OH- and O- decay channels. J Chem Phys 2013; 139:055101. [PMID: 23927286 PMCID: PMC3813476 DOI: 10.1063/1.4815967] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We measure the desorption of anions stimulated by the impact of 0-20 eV electrons on highly uniform thin films of plasmid DNA-diaminopropane. The results are accurately correlated with film thickness and composition by AFM and XPS measurements, respectively. Resonant structures in the H(-), O(-), and OH(-) yield functions are attributed to the decay of transient anions into the dissociative electron attachment (DEA) channel. The diamine induces ammonium-phosphate bridges along the DNA backbone, which suppresses the DEA O(-) channel and in counter-part increases considerably the desorption of OH(-). The close environment of the phosphate groups may therefore play an important role in modulating the rate and type of DNA damages induced by low energy electrons.
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Affiliation(s)
- Omar Boulanouar
- UMR CNRS 6249 Chrono-Environnement, Laboratoire de Chimie Physique et Rayonnements – Alain Chambaudet, LRC CEA, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon cedex, France
| | - Michel Fromm
- UMR CNRS 6249 Chrono-Environnement, Laboratoire de Chimie Physique et Rayonnements – Alain Chambaudet, LRC CEA, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon cedex, France
| | - Christophe Mavon
- UMR CNRS 6249 Chrono-Environnement, Laboratoire de Chimie Physique et Rayonnements – Alain Chambaudet, LRC CEA, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon cedex, France
| | - Pierre Cloutier
- Groupe en Sciences des Radiations, Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Québec J1H 5N4, Canada
| | - Léon Sanche
- Groupe en Sciences des Radiations, Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Québec J1H 5N4, Canada
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Almeida D, Kinzel D, Ferreira da Silva F, Puschnigg B, Gschliesser D, Scheier P, Denifl S, García G, González L, Limão-Vieira P. N-site de-methylation in pyrimidine bases as studied by low energy electrons and ab initio calculations. Phys Chem Chem Phys 2013; 15:11431-40. [PMID: 23743926 DOI: 10.1039/c3cp50548k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Electron transfer and dissociative electron attachment to 3-methyluracil (3meU) and 1-methylthymine (1meT) yielding anion formation have been investigated in atom-molecule collision and electron attachment experiments, respectively. The former has been studied in the collision energy range 14-100 eV whereas the latter in the 0-15 eV incident electron energy range. In the present studies, emphasis is given to the reaction channel resulting in the loss of the methyl group from the N-sites with the extra charge located on the pyrimidine ring. This particular reaction channel has neither been approached in the context of dissociative electron attachment nor in atom-molecule collisions yet. Quantum chemical calculations have been performed in order to provide some insight into the dissociation mechanism involved along the N-CH3 bond reaction coordinate. The calculations provide support to the threshold value derived from the electron transfer measurements, allowing for a better understanding of the role of the potassium cation as a stabilising agent in the collision complex. The present comparative study gives insight into the dynamics of the decaying transient anion and more precisely into the competition between dissociation and auto-detachment.
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Affiliation(s)
- D Almeida
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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