| 摘要: | 積層製造技術具有快速客製化優勢，適合製作多孔性且形狀複雜的組織工程支架，而本研究選用冷凍成型積層製造製作支架。然而，使用冷凍成型積層製造製作複雜外型且具有多孔結構的支架相當困難，因為難以完全去除支撐結構。本研究將開發一種可快速生成且可完全去除支撐結構的「固態水支撐製程」，用以解決上述困難。
首先，本研究改良冷凍成型積層製造的低溫裝置及添加環境控制模組，提升冷凍槽的冷凍能力，以提供製作大尺寸支架及快速生成支撐結構之能力。新的低溫裝置是將銅管與擋水鋼板結合，提高熱傳導效率。改良後的結果顯示，工作平台最低溫由原本-30°C可降至-50°C。從室溫到達-30°C的時間，由150分鐘降為20分鐘。另外，藉由水的相變化得以快速生成支撐結構，液體水經由噴霧閥噴灑在工作平台上，冷凍成固態冰，進而成為支撐結構。支架製作完成後，再利用氣化將支撐結構完全去除。最後，本研究根據文獻及熱像儀分析，決定使用10wt%乙醇水溶液作為支撐材料，並可在35秒內沉積75 55mm²的工作範圍。
為了驗證固態水支撐製程之功效，本研究使用PU/PEO為支架材料，製作圓柱支架。由細胞活性實驗的四唑鹽比色法得知，細胞在使用固態水支撐製作的支架內，經過24小時可生長1.8倍的數量。從動態機械分析得知，使用固態水支撐製作的支架，因膨潤效應導致剛性強度降低，但對於支架回彈能力影響不大。經實驗觀察，將支架擠壓後2秒內可回彈回原來的形狀。而使用固態水支撐製作的支架會產生微奈米的網狀結構，藉由核磁共振光譜法得知網狀結構為支架本身材料。最後，使用固態水支撐製作大型雙倒T通孔支架與Y形管支架。由上述證實本研究之方法可製作大尺寸複雜外型且具有多孔結構的組織工程支架。
;Additive manufacturing technology has the advantage in rapid customization, and it is suitable for the production of tissue engineering scaffolds with high porosity and complex shape. This study is focusing on frozen-form additive manufacturing. However, it was difficult to produce the scaffolds with complex shape and porous structure, because its support structure could not be removed completely. This study developed a support process to rapidly generate the support structure and was removed completely.
Firs, This study improved the uniform cryogenic device module and added environmental control module into frozen-form additive manufacturing to enhance the freezing capacity and produce large complex shape scaffolds and rapidly generate support structure. The retaining steel and the copper tube were combined to become the cooling enclosure, which reduced energy loss. The lowest temperature of the working plate became -50°C from -30°C, and the time for the temperature to reach -30°C was reduced from 150 minutes to 20 minutes. Additionally, the support structure was generated by water phase change. Liquid was sprayed on the working plate through the spray valve, and it was frozen into solid to generate the support structure. Finally, the support structure was completely removed by vaporization. According to the literatures and the result of thermal imaging camera, 10wt% ethanol solution was selected as the support material and deposited onto 75 55mm area in 35 seconds.
In order to verify the effectiveness of the support process, PU/PEO was used as the scaffold material to produce cylindrical scaffolds. The cell viability testing was performed using MTT-assay. The results showed that the number of cells grew 1.8 times in 24 hours. The storage module of the scaffolds was lower with the support process, because of swelling effect, but it had a little effect on the elastic recovery. In the experimental observation, the scaffolds restored origin shape in 2 sec after extrusion. Furthermore, the micro/nano network structure of the scaffold was generated between strand and strand after the support process. The micro/nano network structure was detected by nuclear magnetic resonance spectroscopy, and the results showed that it was the material of the scaffold. Finally, the dual inverted T-type inner channels scaffold and the Y-type scaffold were produced in this study. From the above, this study verity the approach to produce large complex shape and porous structure tissue engineering scaffolds. |
