The possible role of molecular products of cell radiolysis, in particular, hydrogen peroxide molecules, in blocking DNA activity in cancer cells during irradiation with heavy ions is investigated. It is supposed that hydrogen peroxide molecules can form long-lived molecular complexes with DNA atomic groups and, thus, prevent the realization of genetic information in the biological cells. Using the quantum-mechanical approach based on density functional method and implicitly taking into account the aqueous medium, the competitive interactions of water and hydrogen peroxide molecules with DNA nucleic bases have been analyzed. Estimates of the characteristic lifetimes of complexes of water molecules and hydrogen peroxide with atomic groups of DNA allow showing the possibility to block the genetic activity of DNA by hydrogen peroxide in biological cells after their irradiation with ion beams. The effect of DNA blocking in cancer cells could be enhanced by a decrease in the cell temperature.

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过氧化氢分子在癌细胞离子束治疗中的可能作用

研究了细胞辐射分解的分子产物（尤其是过氧化氢分子）在重离子辐射过程中阻断癌细胞DNA活性的可能作用。据推测，过氧化氢分子可以与DNA原子团形成长寿命的分子复合物，从而阻碍了生物细胞中遗传信息的实现。使用基于密度泛函方法的量子力学方法，并隐含地考虑到水性介质，分析了水和过氧化氢分子与DNA核酸碱基的竞争性相互作用。对水分子和过氧化氢与DNA原子基团的复合物的特征寿命的估计，显示了用离子束辐照后，过氧化氢在生物细胞中阻断DNA遗传活性的可能性。DNA阻断在癌细胞中的作用可以通过降低细胞温度来增强。