Nanoscale Dynamics of Radiosensitivity: Role of Low Energy Electrons

Sanche, Léon

doi:10.1007/978-94-007-2564-5_1

Cited by 20 publications

(20 citation statements)

References 120 publications

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“…The results obtained for LEE-irradiated supercoiled plasmid DNA in several investigations are well described in the literature and summarized in authoritative review articles [10,11,35]. These studies have shown that SSBs can occur as a result of DEA at electron energies well below electronic excitation and ionization thresholds (0.8-10 eV) [83,90].…”

Section: Electron Attachment To Short Single-stranded and Plasmid Dnamentioning

confidence: 82%

“…Furthermore, Γ a in Eq. (2) changes in the condensed phase, since new decay channels (e.g., phonon modes) appear and the TMA is formed at lower energy due to the polarization potential induced by the temporarily localized electron [17,35] and possible lowering of the symmetry of the anion state [20]. The dash curve in Figure 1 shows the lower energy of the potential-energy curve of the condensed-phase transient anion AB‾.…”

Section: Modification Of Electron Capture and Decay Of Transient Aniomentioning

confidence: 99%

“…In addition, electron transfer from one molecule to another may occur, and hence provide additional decay pathways for TMAs [36]. For very large biomolecules, such as DNA, electron transfer between elemental subunits also impedes electron localization [35]. Hence, due to intramolecular electron transfer, the probability of TMAs forming on specific subunits can also be reduced.…”

Section: Modification Of Electron Capture and Decay Of Transient Aniomentioning

confidence: 99%

“…To prevent excessive charging, these thinfilm biological samples are deposited onto a metal substrate by spin-coating, lyophilisation (freeze-drying), or molecular self-assembly, as in the case of thiolated DNA on gold substrates [10] and 1,3-diaminopropane layer plasmid on graphite [76]. The LEE-induced damage to plasmid and linear DNA films has then been investigated by (1) measuring electron-stimulated desorption (ESD) of anions, (2) imaging the breaks by atomic force and scanning tunneling microscopies, and (3) analyzing, after bombardment, the change of DNA topology by gel electrophoresis or the molecular content by high-performance liquid chromatography (HPLC) and mass spectroscopy [35,77].…”

Section: Electron Attachment To Short Single-stranded and Plasmid Dnamentioning

confidence: 99%

“…The direct effect of high-energy radiation on DNA, resulting from the presence of GNPs, was first investigated by Zheng and coworkers [35,[214][215][216][217][218]. Relatively thick (~0.3 and 2.9 μm) films of plasmid DNA with or without electrostatically bound GNPs were bombarded with 60 keV electrons.…”

Section: Interaction Of Lees With Dna Bound To Gold Nanoparticlesmentioning

confidence: 99%

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Transient Anions in Radiobiology and Radiotherapy: From Gaseous Biomolecules to Condensed Organic and Biomolecular Solids

Alizadeh¹,

Ptasińska²,

Sanche³

2016

Radiation Effects in Materials

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This chapter focuses on the fundamental processes that govern interactions of lowenergy (1-30 eV) electrons with biological systems. These interactions have been investigated in the gas phase and within complex arrangements in the condensed phase. They often lead to the formation of transient molecular anions (TMAs), and their decay by autoionization or dissociation accompanied by bond dissociation. The damage caused to biomolecules via TMAs is emphasized in all sections. Such damage, which depends on a large number of factors, including electron energy, molecular environment, and type of biomolecule, and its physical and chemical interactions with radiosensitizing agents are extensively discussed. A majority of recent findings resulting from experimental and theoretical endeavors are presented. They encompass broad research areas to elucidate important roles of TMAs in irradiated biological systems, from the molecular level to nanoscale cellular dimensions. Fundamental aspects of TMA formation are stressed in this chapter, but many practical applications in a variety of radiation-related fields such as radiobiology and radiotherapy are addressed.

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Section: Electron Attachment To Short Single-stranded and Plasmid Dnamentioning

confidence: 82%

Section: Modification Of Electron Capture and Decay Of Transient Aniomentioning

confidence: 99%

Section: Modification Of Electron Capture and Decay Of Transient Aniomentioning

confidence: 99%

Section: Electron Attachment To Short Single-stranded and Plasmid Dnamentioning

confidence: 99%

Section: Interaction Of Lees With Dna Bound To Gold Nanoparticlesmentioning

confidence: 99%

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Transient Anions in Radiobiology and Radiotherapy: From Gaseous Biomolecules to Condensed Organic and Biomolecular Solids

Alizadeh¹,

Ptasińska²,

Sanche³

2016

Radiation Effects in Materials

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A Single Subexcitation‐Energy Electron Can Induce a Double‐Strand Break in DNA Modified by Platinum Chemotherapeutic Drugs

et al. 2013

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KeywordsCancer; Cisplatin; DNA damage; Low-energy electrons; OxaliplatinThe sensitization of malignant cells to ionizing radiation is the clinical rationale for the use of platinum-based concurrent chemoradiotherapy (CCRT) for cancer treatment; however, the specific mechanisms of radiosensitization and their respective contributions still remain unknown [1] . Biological mechanisms such as inhibition of DNA repair may contribute to the efficacy of CCRT [2] ; nevertheless, there is a dearth of information on the possible contribution of nanoscopic mechanisms to the generation of lethal DNA lesions such as double-strand breaks (DSB). The present study demonstrates that the abundant near zero-eV (0.5-eV) electrons, created by ionizing radiation during radiotherapy, induce DSB in supercoiled plasmid DNA modified by platinum anticancer drugs (Pt-drugs), but not in unmodified DNA. They do so more efficiently than other types of radiation, including soft X-rays and 10-eV electrons. The formation of DSB by 0.5-eV electrons is found to be a single-hit process. These findings reveal insights into the radiosensitization mechanism of Pt-drugs that can have implications for the development of optimal clinical protocols for platinum-based CCRT and the deployment of in-situ sources of subexcitation-energy electrons (e.g., Auger-electron emitting radionuclides) to efficiently enhance DSB formation in DNA modified by Pt-drugs in malignant cells.Pt-drug molecules react with cellular components, including DNA, RNA and proteins, via ligand exchange at the platinum atom [3] . Binding of Pt-drugs to DNA causes a local distortion of the DNA conformation affecting the physical and chemical properties of the molecule, particularly at the site of platination [4] . These modifications are believed to enhance the effects of radiation on the modified DNA by perturbing processes occurring during the physical and chemical stages of the interaction of radiation with DNA [5] . In an aqueous solution of DNA, cisplatin enhances the formation of DNA strand breaks by the reaction of both hydroxyl radicals and hydrated electrons at the site of platination through CIHR Author ManuscriptCIHR Author Manuscript CIHR Author Manuscript the increased accessibility of these species to sugar moieties and dissociative electron transfer [6] . Additionally, in the presence of Pt-DNA adducts, low energy electrons (LEEs, i.e., electrons of 0-30 eV) have a higher cross section for DNA damage than other types of radiations [7,8] . Previously, we hypothesized that at such energies, an incident electron is captured by a DNA constituent at the platination site to form a local transient negative ion (TNI) via a resonance process, which may subsequently rupture chemical bonds via either dissociative electron attachment (DEA) or dissociative electronic excitation (DEE) [8,9] . To determine the primary mechanism responsible for the enhanced damage to DNA modified by Pt-drugs, in the present study, we investigated the contribution and efficiency of these decay channels in ...

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Basic Interactions

Bauer

2014

Surface Microscopy With Low Energy Electrons

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Nanoscale Dynamics of Radiosensitivity: Role of Low Energy Electrons

Cited by 20 publications

References 120 publications

Transient Anions in Radiobiology and Radiotherapy: From Gaseous Biomolecules to Condensed Organic and Biomolecular Solids

Transient Anions in Radiobiology and Radiotherapy: From Gaseous Biomolecules to Condensed Organic and Biomolecular Solids

A Single Subexcitation‐Energy Electron Can Induce a Double‐Strand Break in DNA Modified by Platinum Chemotherapeutic Drugs

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