Eur. Phys. J. D (2014) 68: 97
https://doi.org/10.1140/epjd/e2014-40775-5

Regular Article

Low-energy-electron interactions with DNA: approaching cellular conditions with atmospheric experiments^*

Group of Radiation Sciences, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Québec, J1H 5N4 Canada

^a e-mail: elahe.alizadeh@usherbrooke.ca

Received: 9 December 2013
Received in final form: 11 February 2014
Published online: 24 April 2014

Abstract

A novel technique has been developed to investigate low energy electron (LEE)-DNA interactions in the presence of small biomolecules (e.g., N_2, O₂, H₂O) found near DNA in the cell nucleus, in order to simulate cellular conditions. In this technique, LEEs are emitted from a metallic surface exposed by soft X-rays and interact with DNA thin films at standard ambient temperature and pressure (SATP). Whereas atmospheric N₂ had little effect on the yields of LEE-induced single and double strand breaks, both O₂ and H₂O considerably modified and increased such damage. The highest yields were obtained when DNA is embedded in a combined O₂ and H₂O atmosphere. In this case, the amount of additional double strand breaks was supper-additive. The effect of modifying the chemical and physical stability of DNA by platinum-based chemotherapeutic agents (Pt-drugs) including cisplatin, carboplatin and oxaliplatin was also investigated with this technique. The results obtained provide information on the role played by subexcitation-energy electrons and dissociative electron attachment in the radiosensitization of DNA by Pt-drugs, which is an important step to unravel the mechanisms of radiosensitisation of these agents in chemoradiation cancer therapy.