Biological Properties Of TiO₂ And Ta₂O₅ Surface Modified By Ion Implantation

Tantalum is chemical inert and resistant to corrosion. It does not react with body fluid and stimulate the human body after being implanted into human body, therefore, tantalum is widely used in the field of orthopaedics. In addition, titanium is widely used in biomedical field because of its inertness to biological environments. The aforementioned superiority of tantalum and titanium stems from their capability in spontaneously forming dense oxide thin films, namely tantalum oxide(Ta2O5) and titanium oxide(TiO2). However, tantalum and titanium were still challenged by bacterial contamination, which may result in serious infections and failure of the indwelled devices. A large number of antibiotics were used to reduce the rate of infection, leading to bacterial resistance. Silver nanoparticles(Ag NPs), a kind of broad-spectrum antibacterial agent with minimal tendency of resistance, were widely studied for antimicrobial applications.In this thesis, the plasma immersion ion implantation(PIII) technique is used to introduce zinc(Zn) and/or silver(Ag) on Ta2O5 and TiO2 coatings and endow the materials with antibacterial activity. The main findings were summarized as following:1. The effect of silver PIII duration on the antibacterial efficacy of tantalum oxide(Ta2O5) or titanium oxide(TiO2) coatings was studied. It was found that the antibacterial activity of the coatings increases as the silver PIII duration being prolonged.2. The effect of UV irradiation on the antimicrobial activity of silver PIII treated tantalum oxide and titanium oxide coatings were studied. The results demonstrated that UV irradiation could be a stimulus for improving the dark antibacterial activity of the fabricated coatings.3. Titanium oxide(TiO2) coating was PIII treated by silver plasma alone(Ag PIII), zinc plasma alone(Zn PIII), silver and zinc plasma successively(Ag+Zn PIII), zinc and silver plasma successively(Zn+Ag PIII), and zinc and silver plasma in situ(Zn/Ag PIII). The antibacterial activity of the materials are ranked as Ag PIII > Zn/Ag PIII> Zn+Ag PIII> Ag+Zn PIII> Zn PIII.4. The cytocompatibility of silver PIII treated tantalum oxide(Ta2O5) coatings was studied, and good compatibility was found.