| Abstract: | 生物可降解植體以及骨固定器械已經被運用在口腔顎面外科與整形外科手術上，這些可降解材料在骨頭癒合過程中能夠幫助固持骨頭破碎片段，並且逐漸的被新生骨所取代而不需二次手術。但是高強度的陶瓷有著自身的缺陷，例如脆性、孱弱的裂縫抵抗性與疲勞易敏性，這些問題限制了高荷重方面的運用。如今，為了使生物可降解醫材達到合適的機械性質與抗菌性，進而使用在緻密骨與骨固定器械上仍是個挑戰。為了這個目的，也發展出由矽酸鈣與明膠所構成具有高強度、可調控降解性與極佳的成骨活性的仿生複合材植體，其並具有抗菌塗層的複合材植體。結果顯示明膠可以顯著的提升壓縮強度及抗衝擊能力；10 wt%明膠複合材具有高的初始強度（166 MPa），並具有潛力運用在高荷重皮質骨的修復及骨破壞固定上。在體外疲勞穩定性與動態浸泡降解實驗中，骨植體分別會被循環應力與浸泡時間所影響，但不受初始的酸鹼值影響（pH 7.4與5.0;生物性上，明膠可以有效的提升人類間葉幹細胞的貼附、增生、分化及礦化。在抗菌塗層評估上，對於培養48小時的金黃葡萄球菌及大腸桿菌的體外抗菌，含銀（0.004%）的抗菌效果差於0.4%的幾丁聚醣，但相似於0.2%的幾丁聚醣與0.4%幾丁寡糖，而幾丁聚醣比幾丁寡糖有較佳的抗菌效果。除了0.4%幾丁聚醣與0.004%的銀塗層(毒性較明顯)，幾丁聚醣及幾丁寡糖的塗層在細胞毒性上沒有顯著的細胞毒性，而細胞實驗中，在幾丁聚醣與幾丁寡糖的塗層表面MG63顯示出顯著的成骨活性，例如：增生、鹼性磷酸?、骨鈣素與鈣沉積表達。因此，0.2%幾丁聚醣與0.4%幾丁寡糖塗層的複合材骨植體具有極大的潛力運用在骨支架與骨破壞固定裝置上。Biodegradable implants and fixation devices have been used for oral, maxillofacical and orthopedic surgery. These materials can maintain bone fractured fragments during the bone healing process, and then be replaced gradually by newly formed bone, without second surgery. The inherent drawbacks of high-strength ceramics, such as brittleness, poor crack resistance and fatigue susceptibility, are limited to load-bearing applications. Up to now, to achieve the adequate mechanical properties and antibacterial ability of biodegradable biomaterials used for cortical bone graft substitutes and fracture fixation devices remains a challenge. To this end, the biomimetic composite implants consisting of the calcium silicate and gelatin with an aim of achieving high strength, controlled degradation, superior osteogenic activity were developed, followed by an antibacterial coating on the potential composite implant. The results showed that the appropriate amount of gelatin positively contributed to failure enhancement in compressive and impact modes. The 10 wt%-gelatin composite with high initial strength (166 MPa) may be a potential implant candidate for cortical bone repair and fracture fixation applications. The in vitro fatigue stability and in vitro dynamic soaking for degradation of the bone implants were apparently affected by cycling stress and soaking time individually, but not by the initial pH environments (7.4 or 5.0). The gelatin can effectively promote attachment, proliferation, differentiation, and formation of mineralization of human mesenchymal stem cells (hMSCs). Regarding the antibacterial coating, the antimicrobial effectiveness of the Ag coating against S. aureus and E. coli was inferior to the 0.4% chitosan (CS) coating, but comparable to those of 0.2% CS and 0.4% chitosan oligosaccharide (COS) coatings after 48 h of culture. CS presented a greater bactericidal effect than COS, which was bacteria-independent. CS and COS coatings had no significant cytotoxicity towards L929 cells while the 0.4% CS and 0.004% Ag coating showed remarkably cytotoxicity. The assays of cell functions showed significantly higher osteogenic activity of MG63 cells grown on CS and COS-coated surfaces by increased attachment, proliferation, alkaline phosphatase, osteocalcin, and calcium deposits production. It was concluded that the 0.2% CS-coated and the 0.4% COS-coated composite bone implants had a large potential to be used in bone grafts and fracture fixation devices. |
