Bald Ilko, Deng Zongwu, Illenberger Eugen, Huels Michael A
Ion Reaction Laboratory, Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, CanadaJ1H 5N4.
Phys Chem Chem Phys. 2006 Mar 14;8(10):1215-22. doi: 10.1039/b514754a. Epub 2006 Jan 18.
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.
我们报告称，10 - 100电子伏特的氩离子（Ar⁺）辐照会对多晶铂基底上凝聚相的生物相关糖分子D - 核糖和2 - 脱氧 - D - 核糖造成严重损伤。动能低至15电子伏特的Ar⁺离子会促使这两种糖分子有效分解，导致大量阳离子和阴离子碎片解吸，包括CH₃⁺、C₂H₃⁺、C₃H₃⁺、H₃O⁺、CHO⁺、CH₃O⁺、C₂H₃O⁺、H⁻、O⁻和OH⁻等。使用同位素标记分子（⁵ - ¹³C D - 核糖和¹ - D D - 核糖）揭示了部分碎片起源的位点特异性，进而揭示了化学键断裂的本质。研究发现，在低至15电子伏特的能量下，这两种分子中的所有化学键都易受离子撞击影响，尤其是内环和外环的C - O键。除了分子碎片化外，还观察到了几种化学反应。少量的O⁻/O碎片夺取氢形成OH⁻。研究发现，H₃O⁺离子的形成与糖分子的羟基有关，并且与母体或相邻分子通过氢夺取或质子转移导致的额外氢损失有关。其他几种阳离子碎片的形成也需要从其母体或相邻分子夺取氢。这些碎片化和反应很可能在肿瘤的电离辐射治疗过程中的实际生物介质中发生，因此具有重要的放射生物学意义。
