Papers by Author: Juta Kroica

Abstract: SnO₂-TiO₂ sol-gel coatings on soda-lime silicate glass heat treated at 500 °C and xerogel specimens also heat treated at 500 °C were investigated in this study. The morphology of 1, 3, 5 and 7 mol% SnO₂ doped titanium oxide coatings were evaluated with a scanning electron microscope (SEM), an atomic force microscope (AFM) and an UV-VIS light spectrophotometer, whilst xerogel structure was analysed with X-ray diffraction spectroscopy (XRD). The physicochemical properties of the TiO₂-SnO₂ systems depended mainly on the Sn-to-Ti ratio. The surface morphology of the layer was compact and homogeneous with no visible cracks. Anatase and rutile phase was found in the tested 1, 3, 5, 7 and 10 mol% SnO₂ doped and heat treated xerogel specimens. Rutile phase content in the heat treated xerogel was reduced, if Sn⁴⁺ content was increased. Photocatalytic activity and antibacterial properties were evaluated as well.

Abstract: Prepared and heat-treated sol-gel ZnO-TiO₂ coatings onto microscope glass slides were characterised by atomic force microscopy (AFM), scanning electron microscopy (SEM), as well as absorption spectra of light has been obtained. Thermally treated xerogels were characterised by X-ray diffraction (XRD). As well as their photocatalytic activity using methyl orange (MO) and observing the colour changes over the time in visible light (VIS) and ultra violet (UV) light has been determined. The influence of ZnO concentration on morphology, photocatalytic activity and antibacterial properties of coatings was analysed. The growth of S. epidermidis on the surface of the samples was inhibited due to photocatalytic properties of coatings.

Abstract: The activity of antibacterial material is conventionally estimated by using an indirect method – a bacteria suspension is inoculated onto a surface, and then the bacteria are collected from the surface and examined as to whether they can form colonies on the agar plate. In the present study, the presence of bacteria was examined by direct detection. Our study is based on FTIR-PAS with an interferometer cantilever detector. Our work discusses the possibility of identifying and distinguishing the presence of different bacteria (Staphylococcus epidermidis and Pseudomonas aeruginosa) and the possibility to evaluate the crystallization processes on the pressed calcium phosphate surface.

Abstract: Biomaterials used in bone repair must satisfy certain criteria in order to perform without undesirable immunological response. They must be biocompatible and should inhibit bacteria adhesion on the surface, that could led to strong inflammatory process and implant failure. Our study reveals a synergistic effect on bioactivity and bacteriostasis effect of the TiO₂ ceramics with different surface properties and provides insight into the design of better biomedical implant surfaces. The results show that UV light irradiation has great impact on hidrophilicity of TiO₂ ceramics, but little effect on the sample bacteriostatic effect and bioactivity. TiO₂ ceramic samples showed no or very low bacterial adhesion. Nevertheless, in vitro bioactivity showed TiO₂ ceramic that was thermally treated at lower temperature. Thus for bone repair it’s suggested to use TiO₂ ceramic sintered at lower temperature in order to provide bioactivity with bacterostatic effect and use UV-light irradiation to improve hidrophilicity.

Abstract: Extrusion is a perspective forming technology for obtaining objects with certain profile, important for the TiO2 application as biomaterial. Extruded samples were calcinated at 1100 °C, thermally treated in different atmospheres: at 1450 °C in air and at 1300 °C in vacuum. An approach was made to examine the adhesion and colonization intensity of Staphylococcus epidermidis and Pseudomonas aeruginosa on TiO2 ceramic in vitro. It was found that Ps.aeruginosa demonstrated higher adhesion and colonization intensity as S.epidermidis and TiO2 samples treated in vacuum demonstrated higher attachment of microorganisms as TiO2 samples treated in air. It was supposed that surface charge promoted the bacterial adhesion on the vacuum treated samples.