Low energy electron stimulated desorption from DNA films dosed with oxygen.
Desorption of anions stimulated by 1-18 eV electron impact on self-assembled monolayer (SAM) films of single DNA strands is measured as a function of film temperature (50-250 K). The SAMs, composed of 10 nucleotides, are dosed with O(2). The OH(-) desorption yields increase markedly with exposure to O(2) at 50 K and are further enhanced upon heating. In contrast, the desorption yields of O(-), attributable to dissociative electron attachment to trapped O(2) molecules decrease with heating. Irradiation of the DNA films prior to the deposition of O(2) shows that this surprising increase in OH(-) desorption, at elevated temperatures, arises from the reaction of O(2) with damaged DNA sites. These results thus appear to be a manifestation of the so-called "oxygen fixation" effect, well known in radiobiology.
Groupe en sciences des radiations, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.
Nasrin
N
Mirsaleh-Kohan
Andrew D
AD
Bass
Pierre
P
Cloutier
Sylvain
S
Massey
Léon
L
Sanche
D000838:Anions / Q000737:chemistry; D001483:Base Sequence; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D013696:Temperature
D000838:Anions; D004277:DNA, Single-Stranded; D005609:Free Radicals; D010100:Oxygen