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Ban L, Gartmann TE, Yoder BL, Signorell R. Low-Energy Electron Escape from Liquid Interfaces: Charge and Quantum Effects. PHYSICAL REVIEW LETTERS 2020; 124:013402. [PMID: 31976689 DOI: 10.1103/physrevlett.124.013402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Indexed: 05/27/2023]
Abstract
The high surface sensitivity and controlled surface charge state of submicron sized droplets is exploited to study low-energy electron transport through liquid interfaces using photoelectron imaging. Already a few charges on a droplet are found to modify the photoelectron images significantly. For narrow escape barriers, the comparison with an electron scattering model reveals pronounced quantum effects in the form of above-barrier reflections at electron kinetic energies below about 1 eV. The observed susceptibility to the characteristics of the electron escape barrier might provide access to these properties for liquid interfaces, which are generally difficult to investigate.
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Affiliation(s)
- Loren Ban
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - Thomas E Gartmann
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - R Signorell
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
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Zhou L, Liu W, Brodeur N, Cloutier P, Zheng Y, Sanche L. Absolute cross sections for chemoradiation therapy: Damages to cisplatin-DNA complexes induced by 10 eV electrons. J Chem Phys 2019; 150:195101. [PMID: 31117770 DOI: 10.1063/1.5090259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In chemoradiation therapy, the synergy between the radiation and the chemotherapeutic agent (CA) can result in a super-additive treatment. A priori, this increased effectiveness could be estimated from model calculations, if absolute cross sections (ACSs) involved in cellular damage are substantially higher, when the CA binds to DNA. We measure ACSs for damages induced by 10 eV electrons, when DNA binds to the CA cisplatin as in chemotherapy. At this energy, DNA is damaged essentially by the decay of core-excited transient anions into bond-breaking channels. Films of cisplatin-DNA complexes of ratio 5:1 with thicknesses 10, 15, and 20 nm were irradiated in vacuum during 5-30 s. Conformation changes were quantified by electrophoresis and yields extrapolated from exposure-response curves. Base damages (BDs) were revealed and quantified by enzymatic treatment. The ACSs were generated from these yields by two mathematical models. For 3197 base-pair plasmid DNA, ACS for single strand breaks, double strand breaks (DSBs), crosslinks, non-DSB cluster damages, and total BDs is 71 ± 2, 9.3 ± 0.4, 10.1 ± 0.3, 8.2 ± 0.3, and 115 ± 2 ×10-15 cm2, respectively. These ACSs are higher than those of nonmodified DNA by factors of 1.6 ± 0.1, 2.2 ± 0.1, 1.3 ± 0.1, 1.3 ± 0.3, and 2.1 ± 0.4, respectively. Since LEEs are produced in large quantities by radiolysis and strongly interact with biomolecules, we expect such enhancements to produce substantial additional damages in the DNA of the nucleus of cancer cells during concomitant chemoradiation therapy. The increase damage appears sufficiently large to justify more elaborate simulations, which could provide a quantitative evaluation of molecular sensitization by Pt-CAs.
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Affiliation(s)
- Limei Zhou
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, People's Republic of China
| | - Wenhui Liu
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, People's Republic of China
| | - Nicolas Brodeur
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté of Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Pierre Cloutier
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté of Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, People's Republic of China
| | - Léon Sanche
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté of Médecine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
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Chen W, Chen S, Dong Y, Cloutier P, Zheng Y, Sanche L. Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons. Phys Chem Chem Phys 2018; 18:32762-32771. [PMID: 27878170 DOI: 10.1039/c6cp05201k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Absolute cross sections (CSs) for the interaction of low energy electrons with condensed macromolecules are essential parameters to accurately model ionizing radiation induced reactions. To determine CSs for various conformational DNA damage induced by 2-20 eV electrons, we investigated the influence of the attenuation length (AL) and penetration factor (f) using a mathematical model. Solid films of supercoiled plasmid DNA with thicknesses of 10, 15 and 20 nm were irradiated with 4.6, 5.6, 9.6 and 14.6 eV electrons. DNA conformational changes were quantified by gel electrophoresis, and the respective yields were extrapolated from exposure-response curves. The absolute CS, AL and f values were generated by applying the model developed by Rezaee et al. The values of AL were found to lie between 11 and 16 nm with the maximum at 14.6 eV. The absolute CSs for the loss of the supercoiled (LS) configuration and production of crosslinks (CL), single strand breaks (SSB) and double strand breaks (DSB) induced by 4.6, 5.6, 9.6 and 14.6 eV electrons are obtained. The CSs for SSB are smaller, but similar to those for LS, indicating that SSB are the main conformational damage. The CSs for DSB and CL are about one order of magnitude smaller than those of LS and SSB. The value of f is found to be independent of electron energy, which allows extending the absolute CSs for these types of damage within the range 2-20 eV, from previous measurements of effective CSs. When comparison is possible, the absolute CSs are found to be in good agreement with those obtained from previous similar studies with double-stranded DNA. The high values of the absolute CSs of 4.6 and 9.6 eV provide quantitative evidence for the high efficiency of low energy electrons to induce DNA damage via the formation of transient anions.
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Affiliation(s)
- Wenzhuang Chen
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China.
| | - Shiliang Chen
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China.
| | - Yanfang Dong
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China.
| | - Pierre Cloutier
- Group in the Radiation Sciences, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - 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 J1H 5N4, Canada
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Feng M, Petek H, Shi Y, Sun H, Zhao J, Calaza F, Sterrer M, Freund HJ. Cooperative Chemisorption-Induced Physisorption of CO2 Molecules by Metal-Organic Chains. ACS NANO 2015; 9:12124-12136. [PMID: 26548479 DOI: 10.1021/acsnano.5b05222] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Effective CO2 capture and reduction can be achieved through a molecular scale understanding of interaction of CO2 molecules with chemically active sites and the cooperative effects they induce in functional materials. Self-assembled arrays of parallel chains composed of Au adatoms connected by 1,4-phenylene diisocyanide (PDI) linkers decorating Au surfaces exhibit self-catalyzed CO2 capture leading to large scale surface restructuring at 77 K (ACS Nano 2014, 8, 8644-8652). We explore the cooperative interactions among CO2 molecules, Au-PDI chains and Au substrates that are responsible for the self-catalyzed capture by low temperature scanning tunneling microscopy (LT-STM), X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), temperature-programmed desorption (TPD), and dispersion corrected density functional theory (DFT). Decorating Au surfaces with Au-PDI chains gives the interfacial metal-organic polymer characteristics of both a homogeneous and heterogeneous catalyst. Au-PDI chains activate the normally inert Au surfaces by promoting CO2 chemisorption at the Au adatom sites even at <20 K. The CO2(δ-) species coordinating Au adatoms in-turn seed physisorption of CO2 molecules in highly ordered two-dimensional (2D) clusters, which grow with increasing dose to a full monolayer and, surprisingly, can be imaged with molecular resolution on Au crystal terraces. The dispersion interactions with the substrate force the monolayer to assume a rhombic structure similar to a high-pressure CO2 crystalline solid rather than the cubic dry ice phase. The Au surface supported Au-PDI chains provide a platform for investigating the physical and chemical interactions involved in CO2 capture and reduction.
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Affiliation(s)
- Min Feng
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Hrvoje Petek
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Yongliang Shi
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Hao Sun
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Jin Zhao
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Florencia Calaza
- Department of Chemical Physics, Fritz-Haber-Institute der Max-Plank-Gesellschaft , Faradayweg 4-6, D-14195 Berlin, Germany
| | - Martin Sterrer
- Department of Chemical Physics, Fritz-Haber-Institute der Max-Plank-Gesellschaft , Faradayweg 4-6, D-14195 Berlin, Germany
- Institute of Physics, University of Graz , Universitätsplatz 5, A-8010 Graz, Austria
| | - Hans-Joachim Freund
- Department of Chemical Physics, Fritz-Haber-Institute der Max-Plank-Gesellschaft , Faradayweg 4-6, D-14195 Berlin, Germany
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Rezaee M, Cloutier P, Bass AD, Michaud M, Hunting DJ, Sanche L. Absolute cross section for low-energy-electron damage to condensed macromolecules: a case study of DNA. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:031913. [PMID: 23030950 PMCID: PMC3815646 DOI: 10.1103/physreve.86.031913] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/24/2012] [Indexed: 06/01/2023]
Abstract
Cross sections (CSs) for the interaction of low-energy electrons (LEE) with condensed macromolecules are essential parameters for accurate modeling of radiation-induced molecular decomposition and chemical synthesis. Electron irradiation of dry nanometer-scale macromolecular solid films has often been employed to measure CSs and other quantitative parameters for LEE interactions. Since such films have thicknesses comparable with electron thermalization distances, energy deposition varies throughout the film. Moreover, charge accumulation occurring inside the films shields a proportion of the macromolecules from electron irradiation. Such effects complicate the quantitative comparison of the CSs obtained in films of different thicknesses and limit the applicability of such measurements. Here, we develop a simple mathematical model, termed the molecular survival model, that employs a CS for a particular damage process together with an attenuation length related to the total CS, to investigate how a measured CS might be expected to vary with experimental conditions. As a case study, we measure the absolute CS for the formation of DNA strand breaks (SBs) by electron irradiation at 10 and 100 eV of lyophilized plasmid DNA films with thicknesses between 10 and 30 nm. The measurements are shown to depend strongly on the thickness and charging condition of the nanometer-scale films. Such behaviors are in accord with the model and support its validity. Via this analysis, the CS obtained for SB damage is nearly independent of film thickness and charging effects. In principle, this model can be adapted to provide absolute CSs for electron-induced damage or reactions occurring in other molecular solids across a wider range of experimental conditions.
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Affiliation(s)
- Mohammad Rezaee
- Groupe en Sciences des Radiations, Départment de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4.
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Jensen ET, Sanche L. Electron transfer reactions for image and image-derived states in dielectric thin films. J Chem Phys 2008; 129:074703. [DOI: 10.1063/1.2969105] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Chemical modification of polystyrene by low-energy (<100 eV) electron irradiation studied by mass spectrometry. J Appl Polym Sci 2008. [DOI: 10.1002/app.27892] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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