本研究的主要目的是利用電腦輔助設計與製造的方法，對組織工程中的細胞支架結構進行探討，主要目標為骨組織支架。骨支架內在結構以具孔洞的單位結構進行設計分析，並利用醫學影像電腦斷層掃瞄得到骨骼輪廓解剖形狀，再將具骨骼輪廓外形之模型與內在孔洞單位結構模型作結合，以構成一CAD三維實體模型。最後利用快速成形技術的製造方式，和適當的材料製成各種的支架模型。在支架內在單位結構設計部份，是利用CAD軟體來進行設計；並將設計完成之支架模型，利用有限元素分析的模擬，在製作支架成品前評估其力學行為，使得骨支架的力學特性更符合需求。

　　在支架內在結構設計部份，改變的參數有孔隙度ヽ孔洞形狀ヽ單位結構形狀與大小。其分析結果顯示，支架的應力與應變值會隨著孔隙度的增加而有顯著的降低；由此可觀察到孔隙度的高低是影響支架力學行為一重要參數。單位結構形狀與孔洞形狀的改變，對於支架力學效能的影響則無顯著的改變。由研究結果可知，支架的設計可藉由改變內在結構之相關參數，以改變支架力學行為的表現，進而影響細胞在支架上的生長。以快速成形技術製作支架方面，由於用於製作支架使用的材料強度太弱，造成製作較小成品時有損毀的現象產生。希望在未來應用更適當的材料來製作骨支架模型。

　　The purpose of this study is to utilize the technologies in computer-aided design (CAD) and manufacturing for the scaffold design and analysis of tissue engineering. The targeted scaffold is for bone tissue. By employing the medical images from Computer tomography, the external geometry of the targeted bone portion could be outlined and integrated with the internal porosity architecture (based on the unit cell) to design the scaffold structure within the CAD system. The scaffold could then be manufactured with rapid prototyping (RP) system using powder materials. For the evaluation of scaffold internal porosity architecture, that is the unit cell, the CAD software was combined with the finite element analysis to pre-evaluate the mechanical behavior of scaffold prior to its fabrication. This allows the designing and production of scaffold to match the pre-required conditions.

　　For the evaluation of unit cell porosity effect, the investigated geometrical parameters including: porosity, pore shape, unit cell shape and size. The results showed that, with the increasing of the scaffold porosity, the maximum stress and strain would redistributing and decreasing significantly. This indicates that porosity is the most important parameter in determining the mechanical behavior of scaffold structure. Modifying the shapes of unit cell or pore, there were no obvious difference in mechanical performance of the scaffold. By changing the scaffold internal porosity parameters, it can affect the scaffold mechanical behavior thus influence the cell growth simultaneously. For the RP process in scaffold manufacturing, due to the low material strength used in this study, for too small sample size the scaffold is very easy to be broken. Applying stronger materials to fabricate bone scaffold is the first problem to be solved in the future.

[1] 張至宏ヽ林峰輝，談硬骨組織工程: 源源不絕的骨骼銀行
科學發展 2002年八月，356期
[2] 曾清秀ヽ呂恒綜ヽ李永全，幫細胞蓋一個家:組織工程用支架
科學發展 2002年八月，356期
[3] E. Feinberg, J. Hollister, W. Halloran,T. Gabe, H. Krebsbach, Image-based biomimetic approach to reconstruction of the temporomandibular joint. Cells Tissues Organs 2001;169:309-321
[4] T. Gabriel, C. David, G. Orton, J. Hollister, E. Feinberg, W. Halloran, Mechanical and in vivo performance of hydroxyapatite implants with controlled architectures. Biomaterials.2002;23:1283-1293
[5] Shou-feng Yang, Kah-Fai Leong, Zhaohui Du, Chee-Kai Chua, The design of scaffolds for use in tissue engineering.Part I.Traditional factors(Review). Tissue Engineering.2001; 7,Number 6
[6] Vassilis Karageorgiou, David Kaplan, Porosity of 3D biomaterial scaffolds and osteogenesis(Review). Biomaterials. 2005;26:5474-5491
[7] Wai Yeong, Chee Chua, Kah Leong and Margam Chandrasekaran, Rapid prototyping in tissue engineering:challenges and potential(Review). TRENDS in Biotechnology.2004 December;22:12
[8] K. Leong, C. Cheah, C. Chua, Solid freeform fabrication of 3-dimension scaffolds for engineering replacement tissues and organs.Biomaterials.2003;24:2363-2378
[9] http://audi.nchu.edu.tw/~wenjea/about%20research%20topics.html
[10]Encyclopedia of materials: Science and Technology(2003,invited) Tissues Engineering Scaffolds.
[11] T. SAMPATH, A. REDDI, Importance of Geometry of the Extracellular Matrix in Endochondral Bone Differentiation. The Journal Cell Biology 1984;98:2192
[12] L.Cima, J .Vacanti , C. Vacanti, D. Ingber, D. Mooney, R. Langer, Tissue engineering by cell transplantation using degradable polymer substrates. Journal Biomech Eng. 1991 May;113(2):143-51.
[13] S.Edwards, W.Mitchell, J.Matthews, E. Ingham, S. Russell, Design of nonwoven scaffold structures for tissue engineering of the anterior cruciate ligament. AUTEX Research Journal,2004;4;No2
[14] http://www.chemnet.com.tw/magazine/200305/index7.htm
[15] D. Baksh, J.Davies, Three-dimensional matrices of calcium polyphosphates support bone growth in vitro and in vivo. Journal of materials science: Materials in medicine.1998;9:743-748
[16] V.Maquet, R.Jerome, Design of macroporous biodegradable polymer scaffolds for cell transplantation. Materials Science Forum 1997;250:15-42
[17] Lin Cheng , Noboru kikuchi, Scott J. Hollister, A novel method for biomaterial scaffold internal architecture design to match bone elastic properties with desired porosity. Journal of Biomechanics. 2004;37:623-636
[18] Wei Sun, Binil Starly, Andrew Darling, Connie Gomez, Computer-aided tissue engineering: application to biomimetic modeling and design of tissue scaffolds. Biotechnol. Appl. Biochem. 2004;39:49-58
[19] Kruyt MC, de Bruijn JD, Wilson CE, Viable osteogenic cells are obligatory for tissue-engineered ectopic bone formation in goats. Tissue Engineering 2003;9(2):327-36.
[20] Barralet JE, Grover L, Gaunt T, Wright AJ, Gibson IR, Preparation of macroporous calcium phosphate cement tissue engineering scaffold. Biomaterials 2002;23(15):3063-72.