RESUMO
The spherical materials TiO2-SiO2-P2O5/CaO, TiO2-SiO2-P2O5/La2O3, and TiO2-SiO2-P2O5/ZnO deposited on the Tokem-250 cation exchanger have been synthesized with an alcoholic solution by the sol-gel method. The macroporous cation exchanger Tokem-250, which has high Ca2+, Zn2+, and La3+ ion selectivity, was used in the present study. This material has the ability to precipitate and mineralize calcium phosphates on its surface in biological media, since it has high porosity, a homogeneous structure with a uniform variation of elements, and the presence of active centers (Si4+, Ti4+) on the surface. The effect of lanthanum and zinc additives on biological properties has been studied. It was established that accumulation of Ca2+ and Mg2+ occurs faster on the surface of TiO2-SiO2-P2O5/ZnO in the SBF (simulated body fluid) model solution, showing higher reaction capacity. The amount of calcium and phosphorus ions on the surface of sample TiO2-SiO2-P2O5/La2O3 is greater due to the ability of lanthanum to coordinate a large number of ions (lanthanum coordination number is 10). The presence of zinc ions in the system causes the partial hemoglobin release from erythrocytes into the supernatant fluid. The samples with lanthanum ions reduce the amount of protein in plasma after incubation, which has a positive effect on the practical application.
RESUMO
The TiO2-SiO2-Ag/fiberglass with antibacterial properties under UV light irradiation was synthesized. The effects of compositions of TiO2-SiO2-Ag/fiberglass, optical, and textural characteristics on the antibacterial activity were studied. The TiO2-SiO2-Ag film was coated on the surface of fiberglass carrier filaments. The temperature effect on the formation of the TiO2-SiO2-Ag film was established by thermal analysis, and the temperature treatment mode was selected as 300 °C for 30 min, 400 °C for 30 min, 500 °C for 30 min, and 600 °C for 30 min. The influence of silicon oxide and silver additives on the antibacterial properties of TiO2-SiO2-Ag films was established. Increasing the treatment temperature of the materials up to 600 °C increased the thermal stability of the titanium dioxide anatase phase, while the values of optical characteristics decreased: the film thickness decreased to 23.92 ± 1.24 nm, the refractive index decreased to 2.154 ± 0.002, the energy of the band gap width decreased to 2.8 ± 0.5, and the light absorption shifted to the visible-light regime, which is important for photocatalytic reactions. The results showed that the use of TiO2-SiO2-Ag/fiberglass allows significant decrease in the value of CFU microbial cells to 125 CFU m-3.
RESUMO
A facile synthesis method was developed to synthesize TiO2-SiO2-P2O5/CaO or TiO2-SiO2-P2O5/ZnO with a core-shell structure. The carboxylic cation exchanger Tokem-250 has a high selectivity for Ca2+/Zn2+ ions and was used in this study. The framework of the material in the shell was TiO2-SiO2-P2O5, and the inner part was filled with CaO (sample TiO2-SiO2/CaO) or ZnO (sample TiO2-SiO2-P2O5/ZnO). A stepwise heat treatment (drying in a drying oven at 60 °C for 30 min, then annealing in a muffle furnace for 30 min at 150, 250, and 350 °C, at 600 °C for 6 h, and at 800 °C for 1 h) was needed to obtain a homogeneous material. The poly(vinyl alcohol) was used as a binding additive. The obtained composites were characterized by a regular structure and highly developed surface. The samples exhibit bioactive properties in the simulated body fluid (SBF) solution, since the surface contains active centers (Si4+, Ti4+) which contribute to mineralization and precipitation of the calcium-phosphate compounds on the surface from biological media. The TiO2-SiO2-P2O5/CaO-PVA samples did not exceed acceptable hemolysis levels for medical materials.
