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Effect of the structure on biological and photocatalytic activity of transparent titania thin-film coatings

Wojcieszak D., Mazur M., Kaczmarek D., Poniedziałek A., Domanowski P., Szponar B., Czajkowska A., Gamian A.

Materials Science Poland

2016

Vol. 34, No. 4

856--862

In this work, the effect of titanium dioxide (TiO2) thin film microstructure on photocatalytic and biological activity was described. The films were prepared by low-pressure and high-energy magnetron sputtering processes. The structural investigations performed by X-ray diffraction revealed that the films from both the processes were nanocrystalline. It was found that TiO2 prepared by low-pressure process had the anatase structure with crystallites in size of 20 nm, while the film deposited in high-energy process had the rutile form with crystallites in size of 5 nm. The analysis of surface topography with the aid of optical profiler showed that all prepared films were homogenous and their roughness was lower than 1 nm. The wettability studies revealed hydrophilic nature of both films. The values of water contact angle obtained for anatase and rutile films were equal to 40° and 49°, respectively. Both types of the thin films were photocatalitycally active, but rutile exhibited higher decomposition rate as compared to anatase. During the photocatalytic reaction in the presence of TiO2-rutile film after 12 hours of UV-Vis irradiation 30 % of phenol was decomposed, whereas in case of TiO2-anatase it was only 10 %. Moreover, the influence of as-deposited coatings on the growth of selected microbes (Staphylococcus aureus, Escherichia coli, Candida albicans) was examined. It was found that the structural properties of TiO2 had an effect on biological activity of these films.

Zastosowanie tokoferolu i kwasu acetylosalicylowego w ochronie tkanki kostnej przed skutkami doświadczalnego zatrucia 2,3,7,8-tetrachloro-dibenzo-p-dioksyną (TCDD)

Dobrzyński M., Bazan J., Gamian A, Rosińczuk-Tonderys J, Parulska O, Całkosiński I.

Rocznik Ochrona Środowiska

2014

Tom 16, cz. 1

300--322

Dioxins are released into the environment as by-products of technological processes, i.a. in the chemical industry, pulp and paper industry, metallurgical industry, textile industry and dyeing industry. Dioxins are a group of compounds recognized by the International Agency for Research on Cancer (IARC) as carcinogens of Group A since 01/06/1997. The carcinogenic action has been demonstrated on animals. Despite stringent obligations arising from the provisions of The Stockholm Convention on Persistent Organic Pollutants on reducing POPs emissions to the environment (including dioxins) emission of these substances is still significant. These compounds often enter the food chain in random or intentional way and accumulate in organisms in the top of the food chain. This leads to the poisoning of the organism and appearance of clinical symptoms. According to the real hazard of poisoning the people, especially employed in the chemical industry, who are exposed to dioxins, research to determine the impact of these xenobiotics on various tissues and organs as well as to develop of effective pharmacological prevention is constantly conducted. Despite of the wide spectrum of the assessment of dioxins biological effects among humans and animals, there are only a few publications evaluating the impact of dioxins on the bone tissue. The main components of the fully functional bone are calcium phosphates and magnesium phosphates. From the proper saturation of bone matrix with salts of these chemical elements (mineralization) depends the hardness and elasticity of the bone. The young bone mineralization is controlled by a group of proteins, from which the most important is osteonectin, osteocalcin and alkaline phosphatase. Many xenobiotics, including dioxins, have a negative influence on the biosynthesis of these proteins. The measurement of calcium and magnesium concentration in bone is one of the methods for assessing bone destruction. The aim of this study was to investigate the effect of 2,3,7,8-tetrachlorodobenzo-p-dioxin (TCDD) in rats on calcium and magnesium levels in bone tissue of their offspring. Moreover the aim of this study was to check whether the administration of the dioxin receptor antagonists – tocopherol and acetylsalicylic acid – can reduce negative effects of dioxin action. Study was performed on 2-day newborns of Buffalo strain rats. Lower levels of calcium and magnesium was found both in cranial vault bones and the knee from newborns of mothers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. It was shown that administration of mothers exposed to 2,3,7,8- tetrachlorodibenzo-p-dioxin tocopherol or acetylsalicylic acid prevent decreases in calcium and magnesium concentrations in the bone tissue of the offspring.