Ondrej Kylian

Effect of different surface nanoroughness of titanium dioxide films on the growth of human osteoblast-like MG63 cells †‡

Cell behavior depends strongly on the physical and chemical properties of the material surface, for example, its chemistry and topography. The authors have therefore assessed the influence of materials of different chemical composition (i.e., glass substrates with and without TiO(2) films in anatase form) and different surface roughness (R(a) = 0, 40, 100, or 170 nm) on the adhesion, proliferation, and osteogenic differentiation of human osteoblast-like MG63 cells. On day 1 after seeding, the largest cell spreading area was found on flat TiO(2) films (R(a) = 0 nm). On TiO(2) films with R(a) = 170 nm, the cell spreading area was larger and the number of initially adhering cells was higher than the values on the corresponding uncoated glass. On day 3 after seeding, the cell number was higher on the TiO(2) films (R(a) = 0 and 40 nm) than on the corresponding glass substrates and the standard polystyrene dishes. On day 7, all TiO(2) films contained higher cell numbers than the corresponding glass substrates, and the cells on the TiO(2) films with R(a) = 40 and 100 nm also contained a higher concentration of β-actin. These results indicate that TiO(2) coating had a positive influence on the adhesion and subsequent proliferation of MG63 cells. In addition, on all investigated materials, the cell population density achieved on day 7 decreased with increasing surface roughness. The concentration of osteocalcin, measured per mg of protein, was significantly lower in the cells on rougher TiO(2) films (R(a) = 100 and 170 nm) than in the cells on the polystyrene dishes. Thus, it can be concluded that the adhesion, growth, and phenotypic maturation of MG63 cells were controlled by the interplay between the material chemistry and surface topography, and were usually better on smoother and TiO(2)-coated surfaces than on rougher and uncoated glass substrates.

Modification of cellulose/chitin mix fibers under different cold plasma conditions

A two step process was used for the cellulose/chitin mix fibers modification: the first one consists in cold plasma activation followed by the second step the reaction with different chemical modifiers by subsequent impregnation or impregnation/coupling reaction. The activation has been performed under the action of four kinds of cold plasma discharges (discharge gases: air, oxygen, nitrogen and argon). The N-isopropylacrylamide, acrylic acid and oleic acid are used as modifiers. The modified samples were characterized by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetry and differential thermal analysis. All results confirm the morphological and structural changes after plasma treatments which determine the modification of the cellulose/chitin mix fibers.Graphical Abstract