Papers by Author: A. Sowinska

Abstract: A diffusion surface layer of Ti3P+Ti-Ni type was produced on Ti6Al4V titanium alloy by a chemical electroless nickel-phosphorous deposition process combined with glow discharge treatment. The microstructure, phase composition, surface topography, corrosion and wear resistance of this surface layer were investigated, as was its biocompatibility with the human Saos-2 cell line. Cells were analysed in terms of cell viability and adhesion. The results showed that the duplex treatment permits production of a layer that has high corrosion and frictional wear resistance and the Ti3P outer zone of this composite layer is characterised by a topography and chemical composition promising high biocompatibility. This new Ti3P+Ti-Ni type layer offers new potential in biomaterials for bone applications in terms of improved tissue ingrowth and long-term use.

Abstract: Cell adhesion to biomaterials and cell proliferation are affected, among others, by the chemical composition and surface microtopography of the biomaterial. These are, in turn, influenced by sterilisation processes. The aim of this study was to evaluate the sensitivity of osteoblasts and fibroblasts to TiN surfaces deprived of an oxide film or with an enhanced oxide film due to sterilisation in plasma or in an autoclave, respectively. Type TiN+T2N+aTi(N) nitrided surface layers were produced under glow discharge conditions and sterilized in plasma Sterrad 100 and in a steam autoclave. The results provide evidence that nitrided surface layers improved wearand corrosion resistance of the titanium alloy and that these features were not influenced by sterilisation procedures that resulted in various oxide films. In vitro study of human fibroblast and osteoblast-like cells cultured on TiN surfaces modified by sterilisation processes showed that cells respond to the presence of an enhanced oxide film by aggregating, exhibiting lower viability and increased apoptosis, while to a surface deprived of oxides, by regular spreading and high viability. It can be concluded that differences in surface composition and topography of the nitrided surface layers due to various types of sterilisation elicit specific cell responses, and plasma sterilisation seems to be optimal for bone implants with this surface layer.