The Long-term Antibacterial Activity Of TiO₂Nanotubes With Embedded Ag₂O Nanoparticles And Their Effects On Osteoblasts

Biomedical titanium (Ti) and its alloys are widely used clinically as hard tissue implants because of their excellent mechanical properties, corrosion resistance, and biocompatibility. However, there are still two serious post-operative complications:prosthetic loosening and implants related infection. Recently, TiO2nanotube (NT) arrays fabricated by electrochemical anodization have captured much interest as biomedical coatings. These highly ordered and vertically oriented NT arrays can effectively improve the biological performance of biomaterials as they can imitate the microstructure of natural bone tissue and extracellular matrix. However, they have inadequate antibacterial ability, which cannot meet all the clinical needs. In this dissertation, TiO2NT arrays with Ag2O nanoparticles embedded in the nanotube wall (NT-Ag2O arrays) are fabricated by TiAg magnetron sputtering and anodization. Their long-term antibacterial activity, cytocompatibility, and the effects on the osteoblasts are also assessed. The main research results are as follows: 1. Uniform TiAg composite coatings with Ag concentration ranging from0to27.23at.%are prepared on pure Ti using magnetron sputtering.2. NT-Ag2O arrays are fabricated by electrochemical anodization. Ag2O nanoparticles are embedded in the amorphous TiO2nanotube wall and the incorporated amounts can be readily controlled by varying the deposition and anodization parameters.3. The noncumulative Ag+release pattern from NT-Ag2O arrays shows an initial rapid release followed by the sustained lower release. The long-term antibacterial activity of the NT-Ag2O arrays stems from the synergistic effect of released Ag+and direct contact with Ag2O nanoparticles.4. NT-Ag2O arrays can well support osteoblasts as there is no appreciable deleterious effects on proliferation, viability and functions of MC3T3-E1cells are exhibited. Cell spreading improvement is observed on NT-Ag2O arrays with appropriate amount of incorporated Ag. Although the NT-Ag2O arrays with a larger Ag content show some hindering effects in the early stage of cell culturing, nearly no influence can be observed after a prolonged period of culturing.