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1
Content available remote

The UV-C Induced Cell Death in Human Malignant Melanoma and Normal Fibroblasts

100%
Panek A., Wiecheć A.
Acta Physica Polonica A
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2016
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vol. 129
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issue 2
172-173
EN
Differences in cellular death between melanoma (Me45) cells and fibroblasts (CCL-110) were investigated after irradiation with UV-C (1.5-15 J/m²) and incubation for up to 48 h. The role of DNA double strand breaks in this process was assessed. Decrease of the Me45 cells viability began about 6 h after irradiation. The fibroblasts viability negatively correlated with the dose applied, since necrosis within this cell population began immediately after irradiation. The enhanced apoptosis of fibroblasts was observed between 6 and 24 h, while for melanoma cells, high level of apoptotic cells was still detected after 48 h. Statistically significant correlation between the percentage of apoptotic cells and DSBs was estimated for both cell lines. The melanoma cells responded differently to the UV-C radiation than did the fibroblasts. These differences were explained by deficiency of the necrotic processes as well as the delay of apoptotic melanoma response to UV-C damage.
2
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In the Search of Electron Correlation Effects in DNA

80%
Wróbel A., Wróbel P.
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|
issue 2
409-412
EN
We discuss the energy scale separation induced in DNA by gaps between molecular orbital states of individual bases and by electron correlations. We also demonstrate how this separation gives rise to effective low energy models of electron transport in DNA.
3
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The Correlation between the Double Helix Quantum Wave in d-Wave Superconductors and Human DNA

80%
Güven Özdemir Z., Aslan Çataltepe Ö., Onbaşlı Ü.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
13-15
EN
The effective mass of the quasiparticles in a d-wave superconducting system has been calculated via magnetization measurements done by SQUID by using the advanced derivative method used in our previous works. Phenomenological analogy between the double helix quantum wave, which does exist within the primitive cell of the d-wave superconductor, and the human DNA was previously made. In this work, the numerical proof of the analogy mentioned has been realized by determining the magnitude of the attractive force of d-wave structure and comparing with the magnitude of the force that holds the double strand of human DNA that are both of the same order of 10^{-10} N. Moreover, the wavelength of the double helix quantum wave of the superconducting system corresponds to ultraviolet region of the electromagnetic spectrum that exactly coincides with the wavelength which is used for exciting the states in human DNA.
4
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FTIR Microspectroscopy in Studies of DNA Damage Induced by Proton Microbeam in Single PC-3 Cells

80%
Lipiec E., Kowalska J., Lekki J., Wiecheć A., Kwiatek W.
Acta Physica Polonica A
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2012
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vol. 121
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issue 2
506-509
EN
In recent years, the Fourier transformed infrared spectroscopy is often applied in studies of biological materials on cellular level. Undoubted advantage of this method is high sensitivity. In presented research the FTIR microspectroscopy was used to analyse the DNA damage in single PC-3 cells (prostate cancer cell line derived from bone metastases) irradiated by counted number of protons. Focused proton microbeam 2 MeV from the Van de Graaff accelerator at the Institute of Nuclear Physics, Polish Academy of Sciences, was used as an irradiation source. Four groups of single cells were irradiated with 1000, 2000, 4000, and 8000 protons per cell, respectively. Following irradiation cells were fixed in 70% ethanol and then analyzed by IR microspectroscopy. Bond analysis of IR spectra served as a base for result analysis. This research has focused on the detection of changes in DNA backbone spectral range (950-1240 cm^{-1}), which could be related to damages such as single and double strand breaks, DNA-DNA, and DNA-protein cross links. Switches and differences in intensity of DNA backbone bands (980-1149 cm^{-1}, 1151-1350 cm^{-1} - symmetric and asymmetric PO^{2-} stretching vibrations, as well as in 1110 cm^{-1} - symmetric stretching of P-O-C band) were observed. Experimental spectra of irradiated and control cells were compared with simulated spectra generated by HyperChem software. The multivariate statistical methods of principal component analysis and hierarchical cluster analysis (Ward's method) were also performed and are discussed.
5
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Applications of Comet Assay for the Evaluation of Genotoxicity and DNA Repair Efficiency in Nanomaterials Research

80%
Panek A., Błażewicz M., Frączek-Szczypta A., Adamczyk J., Wiltowska-Zuber J., Paluszkiewicz C.
Acta Physica Polonica A
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2018
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vol. 133
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issue 2
280-282
EN
The single cell gel electrophoresis method, known as comet assay, is a rapid and sensitive technique for testing novel chemicals and nanoparticles for genotoxicity, monitoring environmental contamination with genotoxins and human biomonitoring. In our studies we check the applicability of this method for the evaluation of biocompatibility of modified (MWNF) and non-modified multi-walled carbon nanotubes (MWNT) as well as potential genotoxicity of mercury(II) nitrate. The obtained results enabled us to conclude that the presence of Hg(NO₃)₂ (p<0.001) and MWNT (p<0.04) cause a significantly higher level of DNA damage in comparison to functionalised nanomaterials MWNF. It was implied that for the three investigated agents only mercury significantly enhanced genotoxic effect of X-ray exposure (p<0.001) and inhibition of radio-induced DNA damage repair. On the contrary, the presence of MWNF have no influence on cellular repair efficiencies, while incubation with MWNT causes apoptosis and consequently results in lack of attached cells. In conclusion, our results confirmed the genotoxicity of mercury and non-modified carbon nanotubes as well as the biocompatibility of modified nanotubes. Additionally, we proved the usefulness of comet method for the evaluation of genotoxicity and DNA repair under the influence of different compounds and nanomaterials.
6
Content available remote

Genotoxicity Study of Carbon Nanoforms using a Comet Assay

80%
Panek A., Frączek-Szczypta A., Długoń E., Nocuń M., Paluszkiewicz C., Błażewicz M.
Acta Physica Polonica A
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2018
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vol. 133
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issue 2
306-308
EN
Carbon nanoforms due to their unique properties can be applied in many areas also in medicine. This article presents preliminary genotoxicity studies of electrospun carbon nanofibers (ECNF). This material, apart from its numerous applications, may also be a candidate for use in medical therapy and diagnostics. Polyacrylonitrile (PAN) nanofibers received in the electrospinning process were carbonized and thereafter subjected to oxidation treatment (ECNF-F). Both types of fibres were analyzed with regard to genotoxic influence on the fibroblast line cells using comet assay. Additionally, comet assay experiments were conducted on biocompatible carbon nanotubes with a hydrophilic surface. The results indicate the key role of the oxidation process in the functionalization of carbon nanoparticles intended for medical purposes.
7
Content available remote

Photoelectrical Behaviour of DNA:PEDT-PSS Functionalised Films

70%
Kažukauskas V., Pranaitis M., Krupka O., Sahraoui B.
Acta Physica Polonica A
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2011
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vol. 119
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issue 2
151-153
EN
We report investigations of functionalized DNA:PEDT-PSS films. The thermal activation energy of the conductivity near the room temperature was about 0.033 eV. The weak carrier trapping was identified by the thermally stimulated current method, proving the fast recombination of light-generated carriers. A "bistable" photoconductivity below the room temperature was evidenced upon the white light excitation. By cooling the samples down to 145-155 K the photoconduction was small. Below this temperature sudden increase of the photoconductivity was observed. Meanwhile by heating the photosensitivity remained enhanced up to 235-245 K. The slow relaxations of the current after the light excitation took place, the time constant of which reached several hundreds of seconds. Such phenomenon could presumably be attributed to the light-induced changes of the sample material morphology and/or associated variation of carrier transport conditions.
8
Content available remote

Spin-Dependent Effects in Helical Molecular Systems with Rashba-Like Spin-Orbit Interaction

70%
Gutierrez R., Cuniberti G.
Acta Physica Polonica A
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2015
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vol. 127
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issue 2
185-191
EN
Strong spin-selective effects have been recently observed in both photoemission and electrical transport experiments in biomolecular systems, opening fascinating possibilities for interfacing semiconductor and biomolecular systems to create highly efficient spintronics devices. From the theoretical and experimental point of view there are strong suggestions that molecular chirality is playing a crucial role. In this study we extend a previously formulated model (R. Gutierrez, E. Díaz, R. Naaman, G. Cuniberti, Phys. Rev. B 85, 081404 (2012)) describing the linear propagation of a charge with spin along the axis of a helical charge distribution. We explore different parameter regions and show that a strong negative spin polarization as observed in the previously mentioned experiments can be obtained with reasonable values of both the electronic coupling elements and the helical field induced spin-orbit interaction.
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