- 學位論文
β-Ti-28Nb-11Ta-8Zr 合金之陽極氧化表面改質添加SrHA及其生物活性研究
Surface Modification and Bioactivity of β-Ti-28Nb-11Ta-8Zr Alloy Treated by Anodic Oxidation and SrHA loading
摘要
由於良好的生物相容性、機械性質與抗腐蝕性，鈦金屬與鈦合金被廣泛應用於人工骨頭植入材料領域，然而大部份材料的楊氏模數值遠大於人骨，因而易導致遮蔽效應(stress-shielding effect)的發生。於本實驗裡，我們採用了本實驗室開發的新型的鈦合金β-type Ti-28Nb-11Ta-8Zr alloy (TNTZ) ，其擁有接近人骨的楊氏模數值以及良好的抗腐蝕性來作為研究材料。除了機械性質差異的問題外，為了提升材料的生物相容性以及抗細菌感染的能力，我們對材料進行表面改質以及添加化合物並做測試，期望開發出理想的骨頭植入材。 首先我們採用陽極氧化法於鈦合金表面成長管狀奈米氧化層結構，奈米管狀結構能增強股母細胞於其表面的貼覆能力並且能做為承載添加化合物的載體；接下來我們用水熱法將金屬鍶以及氫氧基磷灰石合成於奈米管狀結構中：氫氧基磷灰石為人骨的組成主要成分，並且能做為促進骨母細胞成長的前驅物；而金屬鍶的添加除了其本身亦能刺激股母細胞生長外，是為了提升材料整體的抗菌能力。
並列摘要
Due to the good biocompatibility, mechanical properties, corrosion resistance, Titanium and Ti-based alloys are widely applied in the orthopedic implants. However, there are still some problems of the Ti-based alloy implant, such as the elastic modulus of which (cp-Ti, ~105GPa; Ti64,~112GPa) are still far larger than that of real bone (4-40 GPa), which may easily causes stress-shielding effect and subsequently led to the failure of implant. We developed a β-type Ti-28Nb-11Ta-8Zr alloy (TNTZ) with low elastic modulus (49 GPa) as an osseo-compatible material in this study to avoid the problem. Which meets the bone-mimetic condition with improved biocompatibility and corrosion resistance in the environment of simulated body fluid, Hank’s solution. On the other hand, in order to mimic bone extracellular matrix (ECM), the nanotube structure to promote the cell interlocks was carried out by anodic oxidation (AO) with post heat treatment to get crystallization to manufacture crystallized nanotubular oxide layer on the surface. Furthermore, the as-prepared nanostructure oxides serve as a platform utilized to incorporate SrHA inside to devoid of infection during the surgery and assist in surgery and faster healing. Firstly, material characteristics of nanotube TNTZ oxide coating with SrHA were analyzed including surface morphologies by scanning electron microscopy (SEM) and chemical compositions by X-ray photoelectron spectroscopy (XPS) and Energy-dispersive X-ray spectroscopy (EDS). Subsequently, X-ray diffraction (XRD) was used to confirm the crystalline of the nanotube TNTZ oxide structure. Thirdly, cell dehydration and MTT test were conduct to observe the morphology and adhesion of osteoblast on as-prepared NT-TNTZO/SrHA, and the cell proliferation. Finally, in-vitro antibacterial test were applied to observe the antibacterial efficiency. Experimental results indicated that the surface modification through anodic oxidation, diameters of the nanotubes will change with the different apply voltage. Here we applied bias under 50 volt, 60 minutes to grow the nanotube structure as a platform for SrHA (Strontium-hydroxyl apatite) loading to improve the bioability and antibacterial efficiency simultaneously. In the results of SEM image of cell morphology investigation and MTT assay, HA and SrHA-containing provide a more friendly surrounding for osteoblast cells to attach on, and the pseudopod of osteoblast cells can be clearly observed on the SrHA coating treated group. Besides, the enhancements of cell proliferation from crystallinity, SrHA-coating were also found. The final antibacterial tests, qualitative Kirby-Bauer test, inhibited zone observation, reveals that NT-TNTZO/ SrHA effectively inactivate E. coli. Quantitative test of antibacterial efficiency was presented by growth curve of E. coli. The efficiency at least reaches 4 days and 24h respectively in such a strict environment (high volume of bacteria solution). In our study we successfully developed crystal nanotube structure oxide layer loaded with SrHA (NT-TNTZO/SrHA). In the antibacterial test and the in-vitro tests shown that SrHA containing samples enhanced cell viability and antibacterial efficiency simultaneously.