https://doi.org/10.1140/epjd/e2016-70608-4
Regular Article
A novel setup for the determination of absolute cross sections for low-energy electron induced strand breaks in oligonucleotides – The effect of the radiosensitizer 5-fluorouracil*
1 Institute of Chemistry – Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
2 SOLEIL, l’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France
3 Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
4 Department 1 – Analytical Chemistry and Reference Materials, BAM Federal Institute of Materials Research and Testing, Richard-Willstätter Str. 11, 12489 Berlin, Germany
a
e-mail: bald@uni-potsdam.de
Received: 30 September 2016
Received in final form: 20 December 2016
Published online: 14 February 2017
Low-energy electrons (LEEs) play an important role in DNA radiation damage. Here we present a method to quantify LEE induced strand breakage in well-defined oligonucleotide single strands in terms of absolute cross sections. An LEE irradiation setup covering electron energies <500 eV is constructed and optimized to irradiate DNA origami triangles carrying well-defined oligonucleotide target strands. Measurements are presented for 10.0 and 5.5 eV for different oligonucleotide targets. The determination of absolute strand break cross sections is performed by atomic force microscopy analysis. An accurate fluence determination ensures small margins of error of the determined absolute single strand break cross sections σSSB. In this way, the influence of sequence modification with the radiosensitive 5-Fluorouracil (5FU) is studied using an absolute and relative data analysis. We demonstrate an increase in the strand break yields of 5FU containing oligonucleotides by a factor of 1.5 to 1.6 compared with non-modified oligonucleotide sequences when irradiated with 10 eV electrons.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2017
