Si-doped multifunctional bioactive nanostructured films

Abstract

Si-doped multifunctional bioactive nanostructured films (MuBiNaFs) were deposited by DC magnetron sputtering of composite TiC 0.5 + CaO + Si (A) and TiC 0.5 + CaO + Si 3N 4 (B) targets produced by self-propagating high-temperature synthesis method. The films were characterized in terms of their structure, elemental and phase composition using X-ray diffraction, scanning and transmission electron microscopy, electron energy loss spectroscopy, glow discharge optical emission spectroscopy, Raman, and IR spectroscopy. The Ti–Si–Ca–P–C–O–(N) films consisted of TiC(N) as a main phase with a minor amount of TiO x, SiN x, SiO x, SiC, and CaO phases probably mainly in amorphous state at the grain boundaries and COO– groups on the film surface. The excess of carbon atoms in the Ti–Si–Ca–P–C–O–N film (target A) precipitated in a DLC form. The films showed hardness in the range of 26–31 GPa, reduced Young's modulus of 200–270 GPa, and high percentage of elastic recovery of 60–71%. The best Ti–Si–Ca–C–O–N films exhibited low friction coefficient both in physiological solution and Dulbecko modified Eagle medium with fetal calf serum, hydrophilic properties, improved electrochemical characteristics, and excellent impact resistance. Nevertheless, the wear resistance of the Ti–Si–Ca–C–O–N films against Al 2O 3 ball was lower compared with the best Si-free MuBiNaFs. In vitro studies showed that the Si-doped Ti–Ca–C–O–N films possess improved osteoconductive characteristics during early stage of cell/material interaction. The film surface was highly adhesive for IAR-2 epithelial and MC3T3-E1 osteoblastic cells. The films revealed a high level of biocompatibility and biostability in experiments in vivo. The Ti–Si–Ca–C–O–N film (target A) did not show any bactericidal activity during cultivation of bacterial strains both on solid and in liquid Luria Bertani mediums. The film did not reveal any bactericidal and toxic activity against macrophages and therefore did not change bacterial status and defence system of macro-organisms.