Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons

Chen, Wenzhuang; Chen, Shiliang; Dong, Yanfang; Cloutier, Pierre; Zheng, Yi; Sanche, Léon

doi:10.1039/c6cp05201k

Cited by 20 publications

(23 citation statements)

References 46 publications

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“…The determination of absolute cross sections is particularly valuable because the obtained values can be directly compared to absolutec ross sections forr elated processes such as absorption,e xcitation, ionization, electron attachment, dissociative electron attachment, etc.,i fa ll these cross sections can be recorded with the same target configuration and substrate. [41,42] The influence of the telomeres equence and topology on electron-induced strand breakage was up to now unknown, but is studied in detail within the present work. The absolute strand break cross sections for different telomere sequences are determinedf or 8.8 eV electron irradiation.…”

Section: Introductionmentioning

confidence: 96%

“…Strand breaks are visualized in AFM images using the protein streptavidin (SAv), which binds specifically to a biotin (Bt) label at the intact oligonucleotide target strands. The determination of absolute cross sections is particularly valuable because the obtained values can be directly compared to absolute cross sections for related processes such as absorption, excitation, ionization, electron attachment, dissociative electron attachment, etc., if all these cross sections can be recorded with the same target configuration and substrate …”

Section: Introductionmentioning

confidence: 99%

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Low‐Energy Electron‐Induced Strand Breaks in Telomere‐Derived DNA Sequences—Influence of DNA Sequence and Topology

Rackwitz

Bald

2018

Chemistry A European J

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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) is more sensitive to low-energy electrons than an intermixed sequence 5'-(TGT GTG A) confirming the unique electronic properties resulting from G-stacking. With increasing length of the oligonucleotide (i.e., going from 5'-(GGG ATT) to 5'-(GGG ATT) ), 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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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Low‐Energy Electron‐Induced Strand Breaks in Telomere‐Derived DNA Sequences—Influence of DNA Sequence and Topology

Rackwitz

Bald

2018

Chemistry A European J

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“…Most of these modelling procedures [4] are based on Monte Carlo codes, which require accurate and complete [5] electron scattering cross sections in order to simulate single electron tracks into biological media. As is well known, low energy secondary electrons [6] play an important role in these models. For charged particle primary beams (electrons, positrons or ions) these secondary electrons are abundantly generated with energies below 100 eV, and therefore, electron scattering cross section data in the energy range 0-100 eV are especially needed in these types of simulations.…”

Section: Introductionmentioning

confidence: 98%

A Complete Cross Section Data Set for Electron Scattering by Pyridine: Modelling Electron Transport in the Energy Range 0–100 eV

Costa

Traoré-Dubuis

Álvarez

et al. 2020

IJMS

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Electron scattering cross sections for pyridine in the energy range 0–100 eV, which we previously measured or calculated, have been critically compiled and complemented here with new measurements of electron energy loss spectra and double differential ionization cross sections. Experimental techniques employed in this study include a linear transmission apparatus and a reaction microscope system. To fulfill the transport model requirements, theoretical data have been recalculated within our independent atom model with screening corrected additivity rule and interference effects (IAM-SCAR) method for energies above 10 eV. In addition, results from the R-matrix and Schwinger multichannel with pseudopotential methods, for energies below 15 eV and 20 eV, respectively, are presented here. The reliability of this complete data set has been evaluated by comparing the simulated energy distribution of electrons transmitted through pyridine, with that observed in an electron-gas transmission experiment under magnetic confinement conditions. In addition, our representation of the angular distribution of the inelastically scattered electrons is discussed on the basis of the present double differential cross section experimental results.

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“…For example, this situation is present in the results of Chen & al. [31], where the slope ratios (for ) are always be greater than 1, but the uncertainties also include unphysical solutions ( This condition depends largely on the ratio , which in our case for 10 ML and 7.5 ML, is too small compared to our expected experimental uncertainties. To satisfy the criterion, relative slope uncertainties for both thicknesses (10 ML and 7.5 ML) must be less than 5%, which is somewhat unrealistic.…”

Section: Absolute Cross Section Measurementmentioning

confidence: 70%

“…x10 -14 cm 2 , which is in good agreement with the result of Chen & al. [31], but higher compared to those measured previously with (3.8 ± 1.2) x10 -14 cm 2 [19] and (3.0 ± 0.3) x10 -14 cm 2 [12]. Our CS value was calculated from a weighted average to account for the different uncertainties.…”

Section: Absolute Cross Section Measurementmentioning

confidence: 90%

Absolute cross section for DNA damage induced by low-energy (10 eV) electrons: Experimental refinements and sample characterization by AFM

Brodeur

Cloutier

Bass

et al. 2018

The Journal of Chemical Physics

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This work describes multiple experimental improvements for measuring absolute cross sections of DNA damage induced by low-energy electrons (LEE) in nanometer-thick films in vacuum. Measurements of such cross sections are particularly sensitive to film thickness and uniformity. Using atomic force microscopy (AFM) in 70% ethanol, we present a novel and effective method to determine plasmid DNA film thickness and uniformity that combines height histograms and force-distance curves. We also investigate film deposition with DNA intercalated with 1,3-diaminopropane (Dap) on tantalum-coated substrates as a convenient and cost-effective alternative to the previously-used graphite substrate. The tantalum substrate permits deposition of films very similar to those formed on graphite. Using these refinements and further optimizations of the experimental procedure, we measure an absolute cross section of (4.7 ± 1.5) x10-14 cm 2 for conformational damage to a 3197 base-pair plasmid induced by 10 eV electrons, which we believe should be considered as a reference value. I. INTRODUCTION: Ionizing radiation is widely employed in cancer therapy (e.g., in radiotherapy [1, 2], brachytherapy [3] and targeted radionuclide therapy (TRT) [4,5]), as well as in medical diagnostic imaging. In these applications, the radiation dose given to the patient should be known and controlled. In conventional cancer treatments, calculations of the absorbed dose rely on scattering cross sections (CSs) of the primary high-energy radiation. In more sophisticated treatments, such as therapies combining radiation

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Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons

Cited by 20 publications

References 46 publications

Low‐Energy Electron‐Induced Strand Breaks in Telomere‐Derived DNA Sequences—Influence of DNA Sequence and Topology

Low‐Energy Electron‐Induced Strand Breaks in Telomere‐Derived DNA Sequences—Influence of DNA Sequence and Topology

A Complete Cross Section Data Set for Electron Scattering by Pyridine: Modelling Electron Transport in the Energy Range 0–100 eV

Absolute cross section for DNA damage induced by low-energy (10 eV) electrons: Experimental refinements and sample characterization by AFM

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