Crystalline hydrophilic piezoelectric poly(L-lactide) films were created for the first time by drawing at elevated temperatures, additional heat treatment and alkaline etching. The effect of different drawing ratios (between 1 and 7 times the original size), drawing temperatures (in the 70 - 100 °C range), drawing rates (from 1 to 300 mm/min) and post-processing treatments (heat treatments at 140 °C or 160 °C and etching in a NaOH/water/methanol mixture) was examined and compared. Optimal conditions (drawing ratio of 5, drawing temperature at 90 °C, drawing rate of 40 mm/min, postprocessing heat treatment at 140 °C and etching for 20 h in a 0.04M solution of NaOH in a 70/30 V/V water/methanol mixture) for the highest crystallinity and Raman-spectra-based order ratio, the largest surface roughness, the best piezoelectric properties and the highest hydrophilicity were discovered.
COBISS.SI-ID: 32824615
We investigated interactions between apatite nanoparticles and their composites with gold with the surface of bacterial cells and finally obtained antimicrobial effect. For that purpose we described a novel procedure that enables kinetics of bacterial growth in the presence of NPs to be followed with high time resolution, high sensitivity, and without sampling during the kinetic study. We showed the applicability of the Presto Blue method for the case of HAp/Au/arginine NPs, which can be extended to various types of metallic NPs and other biomaterials with similar characteristics that can interact non-specifically with detection method. The method is a very easy, economical, and reliable option for testing NPs designed as novel antimicrobials.
COBISS.SI-ID: 32086567
We investigated effect of magnetic stimulation to cellular life. Magnetic dipole interactions among adjacent nanoparticles were more pronounced in their powders than in their colloidal formulations. Nanoparticles delivered as powders were thus more responsive to the magnetic field, but exhibited reduced uptake in bone and brain cancer cells. Alternate magnetic field elicited a more rapid heat generation in cell culture media supplemented with the magnetic powders, the nanoparticles dispersed in the same media were uptaken by the cancer cells more copiously. The cellular uptake proved to be more crucial in defining the effect on cell survival, given that suspended formulations elicited a greater degree of cancer cell death in the magnetic field compared to the powder-containing formulations.
COBISS.SI-ID: 32437543
We investigated interactions of TiO2 nanotubes with high electron density at the surface with blood cells. The results showed that the surface of the annealed TiO2 nanotubes acts anti-thrombogenically, since the whole-blood derived platelets do not adhere nor activate readily on such samples, unlike on the surface of amorphous TiO2 nanotubes and plain Ti foil. Therefore, the anatase crystal phase of TiO2 nanotubes could be beneficial for stent applications.
COBISS.SI-ID: 1533354
Using Monte Carlo simulations we explored shapes of vesicles, as cell-like models, that contain active curved membrane proteins, in three-dimensions. The activity of the proteins is in the form of protrusive forces that push the membrane outwards, as may arise from the cytoskeleton of the cell due to actin or microtubule polymerization occurring near the membrane. For proteins that have an isotropic convex shape, the additional protrusive force enhances their tendency to aggregate and form membrane protrusions (buds). In addition, we find another transition from deformed spheres with necklace type aggregates, to flat pancake-shaped vesicles, where the curved proteins line the outer rim.
COBISS.SI-ID: 5646187