Damage induced to DNA by low-energy (0-30 eV) electrons under vacuum and atmospheric conditions.

Emilie Brun (1) , Pierre Cloutier (2) , Cécile Sicard-Roselli (3) , Michel Fromm (4) , Léon Sanche (2)

1 G2ELab - Laboratoire de Génie Electrique de Grenoble
2 Centre for Research in Radiooncology
3 LCPO - Laboratoire de Chimie Physique D'Orsay
4 LCPR - Laboratoire de chimie physique et rayonnements (UMR E4)

In this study, we show that it is possible to obtain data on DNA damage induced by low-energy (0-30 eV) electrons under atmospheric conditions. Five monolayer films of plasmid DNA (3197 base pairs) deposited on glass and gold substrates are irradiated with 1.5 keV X-rays in ultrahigh vacuum and under atmospheric conditions. The total damage is analyzed by agarose gel electrophoresis. The damage produced on the glass substrate is attributed to energy absorption from X-rays, whereas that produced on the gold substrate arises from energy absorption from both the X-ray beam and secondary electrons emitted from the gold surface. By analysis of the energy of these secondary electrons, 96% are found to have energies below 30 eV with a distribution peaking at 1.4 eV. The differences in damage yields recorded with the gold and glass substrates is therefore essentially attributed to the interaction of low-energy electrons with DNA under vacuum and hydrated conditions. From these results, the G values for low-energy electrons are determined to be four and six strand breaks per 100 eV, respectively.

Domaines: Chimie théorique et/ou physique

Emilie Brun, Pierre Cloutier, Cécile Sicard-Roselli, Michel Fromm, Léon Sanche. Damage induced to DNA by low-energy (0-30 eV) electrons under vacuum and atmospheric conditions.. Journal of Physical Chemistry B, 2009, 113 (29), pp.10008-13. ⟨10.1021/jp902540k⟩. ⟨hal-00515989⟩