РФС дослідження плівок тиміну на полікристалічній поверхні окисиду титану

Abstract

Розроблено методику одержання плівки тиміну на поверхні окисненої титанової фо-льги. Досліджено структуру шару тиміну на поверхні полікристалічного ТіОх методом рентгенівської фотоелектронної спектроскопії (РФС). Проаналізовано можливі меха-нізми взаємодії біомолекул тиміну з поверхнею оксиду титану.

Разработана методика получения пленки тимина на поверхности окисленной титановой фольги. Проведено ис-следование структуры слоя тимина на поверхности поликристаллического ТіОх методом рентгеновской фото-электронной спектроскопии (РФС). Проанализированы возможные механизмы взаимодействия биомолекул ти-мина с поверхностью оксида титана.

Purpose. Information biomolecules have attracted increasing attention as interest in nanoscience and nano-technology of biomaterials has appeared. Recent studies have demonstrated that nano-TiO2 induces DNA dam-age and increase the risk of cancer and the mechanism might relate to oxidative stress. To our knowledge, no detailed spectroscopic study is reported on thymine on TiOx surface. Therefore, the aim of this work is study of the thymine biomolecules interaction with the polycrystalline titanium oxide by X-Ray photoelectron spec-troscopy (XPS). Methods. Titanium oxide TiOx on the surface of polycrystalline titanium foil was prepared according to the method described in [3]. The thermal evaporation of thymine at 385 K took place in the preparation chamber (pressure 1.4×10−5 Pa). Al Kα radiation (1486.6 eV) was used to measure the XPS core levels spectra of O1s, C1s, N1s and Ti 2p3/2 with total resolution of 1 eV. Curve fitting was performed after a Shirley background subtraction by a Lorenzian–Gaussian method. Results. The thymine layer (d=13.66 Å) on the surface of titanium oxide was obtained by thermal deposition in vacuum. Analysis of the measured XPS spectra shows that the N 1s spectra can be divided into two regions above 400 eV and around 398– 399 eV. A higher energy peak is attributed to amino –N- sites that connect with single bonds. A peak at the lower binding energy can be attributed to imino species that include a double N═C bond. C 1s core level spectra contains components that can be uniquely assigned to the hydrocarbons C─C, C─H, carbon bound to nitrogen C─N, N─C─N, amide carbon N─C═O, and urea carbon N─C(═O)─N with characteristic binding energies of approximately 285, 286–287, 288, and 289 eV, respectively. The heat-ing in vacuum at T=50, 75, 100, 125, 150 and 200°C does not effect on the structure of the sample and the film thickness of thymine film. Conclusions. The polycrystalline titanium oxide layer on the Ti foil was obtained. The thin film of thymine on the titanium oxide surface has was obtained by thermal evaporation in vacuum. XPS investigation of influence of thermal treatment on X-Ray photoelectron spectra of thymine thin film showed that the thickness of the film to 200˚C does not almost change. This indicates the formation of stable chemical bonds between the molecules C5H6N2O2 and the titanium oxide surface.