title: 10-100 eV Ar+ ion induced damage to D-ribose and 2-deoxy-D-ribose molecules in condensed phase.
abstract: We report that 10-100 eV Ar+ ion irradiation induces severe damage to the biologically relevant sugar molecules D-ribose and 2-deoxy-D-ribose in the condensed phase on a polycrystalline Pt substrate. Ar+ ions with kinetic energies down to 15 eV induce effective decomposition of both sugar molecules, leading to the desorption of abundant cation and anion fragments, including CH3+, C2H3+, C3H3+, H3O+, CHO+, CH3O+, C2H3O+, H-, O-, and OH-, etc. Use of isotopically labelled molecules (5- 13C D-ribose and 1-D D-ribose) reveals the site specificity for some of the fragment origins, and thus the nature of the chemical bond breaking. It is found that all of the chemical bonds in both molecules are vulnerable to ion impact at energies down to 15 eV, particularly both the endo- and exocyclic C-O bonds. In addition to molecular fragmentation, several chemical reactions are also observed. A small amount of O-/O fragments abstract hydrogen to form OH-. It is found that the formation of the H3O+ ion is related to the hydroxyl groups of the sugar molecules, and is associated with additional hydrogen loss from the parent or adjacent molecules via hydrogen abstraction or proton transfer. The formation of several other cation fragments also requires hydrogen abstraction from its parent or an adjacent molecule. These fragmentations and reactions are likely to occur in a real biomedium during ionizing radiation treatment of tumors and thus bear significant radiobiological relevance.
authors.affiliation: Ion Reaction Laboratory, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, CanadaJ1H 5N4.
authors.forename: Ilko
authors.initials: I
authors.lastname: Bald
authors.forename: Zongwu
authors.initials: Z
authors.lastname: Deng
authors.forename: Eugen
authors.initials: E
authors.lastname: Illenberger
authors.forename: Michael A
authors.initials: MA
authors.lastname: Huels
mesh_terms: D001128:Argon; D003855:Deoxyribose / Q000737:chemistry / Q000528:radiation effects*; D012266:Ribose / Q000737:chemistry / Q000528:radiation effects*
chemical_list: D003855:Deoxyribose; D001128:Argon; D012266:Ribose