Damage induced to DNA by low-energy (0-30 eV) electrons under vacuum and atmospheric conditions.
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.
Brun
Emilie
E
Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud 11, Bat. 350, 91405 Orsay Cedex, France.
Cloutier
Pierre
P
Sicard-Roselli
Cécile
C
Fromm
Michel
M
Sanche
Léon
L
D001272:Atmosphere; D004249:DNA Damage; D004269:DNA, Bacterial / Q000737:chemistry*; D004583:Electrons; D004926:Escherichia coli / Q000737:chemistry; D014618:Vacuum; D014965:X-Rays
D004269:DNA, Bacterial