| Abstract: | 開發具生物活性之高荷重型植體一直是生醫界企求目標，鈦和鈦合金是目前所使用 的金屬植入材中最具潛力的，因其具有抗腐蝕性、低密度及優異機械性質，然其表面並 不具有活性，無法直接與骨骼產生生物鍵結。此外，牙齦變色及牙周植體炎亦是臨床常 見問題。由於優異生物相容性、耐磨耗及美觀性，陶瓷已廣泛使用在承載負荷的醫學器 材，如全髖膝關節置換及牙科修補。氧化鋯更具有機械強度與韌性、體內穩定性等優點， 然而氧化鋯不具骨引導性，且其遠大於皮質骨(20 GPa)的高彈性係數(200 GPa)將造成應 力集中，導致骨破損。因此，需要進一步發展高性能的氧化鋯基底植體。 研究荷重性植體的共同目標就是設計能支撐細胞與組織成長，機械相容性，及避免 細菌貼附的生物材料。雖然現已有商用氧化鋯，但追求高品質仍是關注的議題。矽酸鈣 因高骨形成性可用做骨移植材；明膠與幾丁聚醣因其優異生物相容性、生物降解性而使 用在骨移植材與藥物載體。本計畫將驗證生物活性矽酸鈣與高分子加入氧化鋯，不僅降 低氧化鋯彈性係數，且提升骨形成性、機械相容性與抗菌性，以符合皮質骨重建需求， 此研究成果將開啟氧化鋯取代鈦植體的新研究方向。 本計畫三年中第一年計劃將分析物理化學性質及機械性質，最佳化含矽酸鈣-氧化 鋯新式植體；第二年將分析體外生物活性與骨形成性。最後一年將明膠與幾丁聚醣導入 微孔植體，以降低彈性係數與提升生物功能，物理化學性質、機械性質、骨形成性及抗 菌性研究為本年度分析重點。本三年計畫兼顧基礎研究及醫學應用，預期此三年研究成 果在生醫材料領域上會有其顯著效能。
The efforts of development of bioactive implants for load-bearing applications have been made in the field of biomedical engineering. Titanium and titanium alloys are proven to be potentially suitable implant materials owing to its corrosion resistance, low density and superior mechanical properties. Unfortunately, like most metals, titanium exhibits poor bioactive properties and fails to bond to the bone tissues. In addition, the problems such as gingival tarnishing and peri-implantitis have been reported in the dentistry. Ceramics are widely used in load-bearing biomedical applications, such as total hip and knee replacements and dental restorations, because of to their excellent biocompatibility, wear resistance and aesthetics. Zirconia ceramics have several advantages over other ceramic materials, because of the merits such as high mechanical strength and toughness and chemical stability in vivo. However, this material has no direct bone bonding properties or osteoconduction behavior. More specially, the higher elastic modulus of ZrO2 (200 GPa) than that of cortical bone (20 GPa) can cause stress concentrations within the surrounding bone tissue, resulting in bone fractures. Further research is required to develop a high efficacy zirconia-based material candidate. A common objective in load-bearing implant materials research is the design of biomaterials that support cell and tissue growth, and possess mechanical compatibility, along with preventing from bacterial adhesion. To pursue the high properties is still a concerned theme, although commercial ZrO2 systems are available today. Calcium silicate-based materials have gained increasing interest for use as bone substitute materials because of their high osteogenesis. Gelatin and chitosan have been widely applied in the biomaterials including bone graft materials and drug carriers because of its excellent biocompatibility and biodegradability. This project will support the hypothesis that the incorporation of a bioactive calcium silicate and polymer not only reduces the modulus of tough ZrO2 implant, but also it enhances biologic properties, mechanical compatibility and antibacterial activity of the implants that can meet the reconstruction requirement of cortical bone. The achievements of the present project can open a new direction alternative to titanium implants. In the first year, the objective will optimize at preparation of calcium silicate-containing ZrO2 implants. Physicochemical properties and mechanical properties of the materials will be performed. Next, the in vitro bioactivity and osteogenesis for the novel materials will be assayed. In the third year, gelatin and chitosan is infiltrated into the porous implant, thus a great reduction of modulus and enhancement of biofunction can be achieved by assaying physicochemical properties, osteogensis and bacteriostatic activity of the biomimetic implants. Combination of basic science and medical practice, results of this three-year research are expected to have a significant potency in the areas of biomaterials science. |
