Inga Narkevica

Effects of Surface Modification of Titania on In Vitro Apatite-Forming Ability

Surface properties of a material play a significant role in manipulating biological response of living body to artificial materials. The aim of this work was put on bioactivity assessment of TiO2 ceramic after thermal treatment and further surface activation with UV-light. The in vitro apatite-forming ability was examined by soaking the samples into the simulated body fluid for several days. The research shows that nanostructural surface and UV irradiation accelerates formation of apatite on TiO2 pellets.

Electrophoretic Deposition of TiO2 Nanoparticles on Dense TiO2-x Ceramic Electrodes

TiO2 nanoparticles were electrophoretically deposited on the dense TiO2-x ceramic electrodes from suspension containing TiO2 nanoparticles, isopropanol as a solvent and triethanolamine as dispersant. The effect of deposition parameters including deposition voltage (10 to 60 V) and deposition time (10 to 40 min) on the microstructure and deposition yield was examined. It was found that the thickness of coating increased with increasing deposition time and deposition voltage. However, it affected the quality of obtained coating e.g. cracks and holes were observed. Optimizing deposition parameters homogeneous coating with smooth microstructure and limited surface damage can be obtained. Thermal treatment of the coating in the temperature range from 700 to 1100 °C causes anatase to rutile phase transformation. Crack formation was noted during sintering due to the phase transformation and thermal stresses.

Sr- and/or Mg-Containing Nanocrystalline Hydroxyapatite: Study from Synthesis to Calcined Products

In this work, nanocrystalline hydroxyapatite (HAp) powders were synthesized through wet precipitation method by adjusting the reaction temperature between 0 °C and 5 °C. The influence of biologically active Mg and Sr addition on HAp crystalline structure and thermal behavior was assessed. In all synthesis, nanocrystalline and/or amorphous HAp was found to be the major phase, and was accompanied by Ca(OH)2 as the minor phase. Results suggested that Sr and Mg have an impending effect on nucleation, crystallization and thermal stability of HAp. The addition of Sr or Mg promoted deviation from stoichiometry and formation of amorphous components, which affected thermal stability and sintering behavior of the synthesis products.

In Vitro Bioactivity and Bacteriostasis Effect of Thermally Treated and UV-Light Irradiated TiO2 Ceramics

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.

The influence of thermal treatment conditions on the properties of TiO2 ceramics

The influence of thermal treatment conditions on titanium dioxide ceramics phase transformation, microstructure, physico-mechanical and electrical properties was studied. TiO2 ceramic was prepared using extrusion technology and thermal treatment in air and subsequent annealing under high vacuum conditions. It has been observed that intense TiO2 ceramic mass sintering occurs over the temperature ranging from 950 °C to 1100 °C. It is accompanied by crystallographic modification change from anatase to rutile. Ceramic sample annealing in vacuum causes formation of nonstoichiometric titanium oxide ceramics and as a result electrical conductivity of the material significantly increases. Using extrusion process relatively dense and mechanically resistant ceramic material can be obtained that can be used in different technological processes.

Electrochemical Studies of Nonstoichiometric TiO2-x Ceramic

TiO2 ceramic was prepared using extrusion technology and thermal treatment in two stages: sintering in air and subsequent annealing under high vacuum conditions. Sample thermal treatment in high vacuum conditions causes formation of nonstoichiometric titanium oxide ceramic. As a result electrical conductivity of the material significantly increases. Such a material can be used for electrode production for electrochemical water treatment.