| Summary: | 碩士 === 國立中興大學 === 生醫工程研究所 === 105 === There is no optimal solution for the treatment of large or non-healing bone defects to date. All currently available therapies have important drawbacks; for example, the bone implants available today are mostly confronted with the problem of designing shape for wounds and falling off easily. The technique of selective laser melting (SLM) is capable of producing intricately designed three-dimensional (3D) structure. However, how to create a biocompatible interface between those SLM-produced bone implants and living tissues remains a challenge. This study aims at the creation of biocompatible interface on the surface of SLM-produced Ti6Al4V scaffold for implantation. Since there are semi-molten powder particles on the surface of SLM-produced Ti6Al4V, those particles are abraded and finally result in tissue inflammation and apoptosis. Here, Ti6Al4V specimens were cleaned in ultrasonic bath to remove most of the particles and followed by electrolytic polishing process in sulfuric acid/methanol solution at 8 volts under the low temperature to effectively improve the surface flatness. Then, the technique of anodic oxidation (AO) was applied to create surface nanostructure on the flat SLM-produced Ti6Al4V in fluorine-containing ethylene glycol electrolyte at 10 volts and 60°C for 10 min to obtain uniform titania nanotubes (TNTs). The samples were chemically modified in 1% 3-aminopropyltrimethoxysilane (APTMS) ethanolic solution for 2 h. After that, the APTMS-modified TNTs were immersed in the simulated body fluid (SBF) for 24 h to complete the surface modification process of SLM-produced Ti6Al4V. The TNTs were observed with an average diameter of about 14.5±2.7 nm on the surface of SLM-produced Ti6Al4V alloys. Electrolytic polishing and anodization can effectively remove the residual particles caused by SLM process. Self-assembled layer with the end of amine functional group was formed on the surface of the TNTs. The APTMS-modified TNTs specimens were further coated a thin film of hydroxyapatite (HA), which could improve the abilities of osteoconduction and osteoinduction with intrinsic bone tissue. The C2C12 cells and their differentiated ones were used to evaluate the in vitro biocompatibility tests. Highly ordered TNTs array effectively improved the surface roughness and increased the surface area. The unmodified and modified SLM-produced Ti6Al4V cylinders were implanted into the distal femur of New Zealand white rabbit for in vivo observation. The nanostructures were still obvious on the surface of anodized and chemically modified SLM-produced Ti6Al4V after HA coating. The synergistic effects of nanostructures, -NH2 and HA could improve biocompatibility of SLM-produced Ti6Al4V.
|
|---|
