hrvatski

Promjene vibracijskih svojstava deoksiribonukleinske kiseline pod utjecajem ionizirajućeg zračenja

In this research, we were investigating changes in the vibrational properties of the deoxyribonucleic acid caused by ionizing radiation using infrared spectroscopy with Fourier transformation (FTIR). Samples were prepared by dissolving commercial Salomon DNA in 10 mM NaCl solution. The resulting solution had a concentration of 5 g/L of DNA. The DNA solution was stored in multiple containers from which each had a volume of 400 microL. These DNA containers were irradiated with 1.24 MeV photons energy on Leksell Gamma Knife that is used at brain radiosurgery (referent dose absorption rate of 1, 553 Gy/min). Dimensions and the material of the container were carefully considered so that we were able to produce a uniform dose delivery through the targeted volume. During irradiation, DNA container has been fixed in the middle of the spherical phantom made out of the tissue equivalent material (ABS plastics). An additional set of identical DNA solution was irradiated on Gulmay Medical roentgen device for skin radiotherapy using 100 keV photons energy (referent dose absorption rate of 9.8 Gy/min). Any beam attenuation was ignored since the irradiated layer of DNA was only 0.65 mm thick. In the latter case, DNA samples were irradiated so we hade a wide range of absorbed dose for targeted volume: 0.1, 0.5, 1, 5, 10, 50 and 100 Gy. Irradiated DNA was pipetted on a silicon plate as an optical window and then dried in the vacuum pump until a thin DNA film was formed. FTIR spectrum was obtained in transmission mode with 64 scan accumulations in the range from 650 - 4000 cm-1 with the resolution of 4cm-1 and automatic solution corrections. Normalization and baseline correction was performed using program Kinetics as part of the MatLab software while the additional spectra processing was performed using eFTIR software. Recorded spectra of irradiated DNA do not show any significant changes in the intensity nor the shift of the characteristic bands in the base region of the DNA. However, the intensity of the DNA has been slightly changed in the region of the backbone vibrations which is more prominent for higher absorbed doses.

DNA, ionizirajuće, zračenje, spektri, gama, nož, rendgen, vibracije

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