title: Hyperthermal (1-100 eV) nitrogen ion scattering damage to D-ribose and 2-deoxy-D-ribose films.
abstract: Highly charged heavy ion traversal of a biological medium can produce energetic secondary fragment ions. These fragment ions can in turn cause collisional and reactive scattering damage to DNA. Here we report hyperthermal (1-100 eV) scattering of one such fragment ion (N(+)) from biologically relevant sugar molecules D-ribose and 2-deoxy-D-ribose condensed on polycrystalline Pt substrate. The results indicate that N(+) ion scattering at kinetic energies down to 10 eV induces effective decomposition of both sugar molecules and leads to the desorption of abundant cation and anion fragments. Use of isotope-labeled molecules (5-(13)C D-ribose and 1-D D-ribose) partly reveals some site specificity of the fragment origin. Several scattering reactions are also observed. Both ionic and neutral nitrogen atoms abstract carbon from the molecules to form CN(-) anion at energies down to approximately 5 eV. N(+) ions also abstract hydrogen from hydroxyl groups of the molecules to form NH(-) and NH(2) (-) anions. A fraction of OO(-) fragments abstract hydrogen to form OH(-). The formation of H(3)O(+) ions also involves hydrogen abstraction as well as intramolecular proton transfer. These findings suggest a variety of severe damaging pathways to DNA molecules which occur on the picosecond time scale following heavy ion irradiation of a cell, and prior to the late diffusion-limited homogeneous chemical processes.
authors.affiliation: Ion Reaction Laboratory, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Zongwu
authors.initials: Z
authors.lastname: Deng
authors.forename: Ilko
authors.initials: I
authors.lastname: Bald
authors.forename: Eugen
authors.initials: E
authors.lastname: Illenberger
authors.forename: Michael A
authors.initials: MA
authors.lastname: Huels
mesh_terms: D004247:DNA / Q000737:chemistry / Q000528:radiation effects; D004249:DNA Damage / Q000528:radiation effects*; D003855:Deoxyribose / Q000737:chemistry*; D005334:Fever; D020450:Heavy Ions; D007700:Kinetics; D013058:Mass Spectrometry; D009584:Nitrogen / Q000737:chemistry*; D012266:Ribose / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D003855:Deoxyribose; D012266:Ribose; D004247:DNA; D009584:Nitrogen