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溶劑澆鑄/粒子過濾法結合模流分析應用於三維多孔性生物鼻支架

Application of Solvent Casting/Particle Leaching Method in Combination with Moldflow Analysis in Three-dimensional Porous Nasal Scaffolds

摘要


背景:本研究主要是應用溶劑澆鑄/粒子過濾法(solvent casting/particle leaching method),結合模流分析(Moldflow analysis),製作並研究以生醫高分子聚乳酸(PLA; polylactic acid)和聚甘醇酸(PLGA; polylactide-co-glycolide)爲村料的L型鼻用多孔性生物支架。 方法:實驗分成兩部份,首先以溶液澆鑄/粒子過濾法(solvent casting/particulate leaching method)將生醫高分子材料(聚乳酸或聚甘醇酸)製作出來的生物多孔支架,切取2-3mm厚的薄片,以掃描式電子顯微鏡(scanning electron microscope)觀察其孔連接狀況及孔洞分佈情形;以壓汞儀(Mercury Porosimetry)測量孔隙率;以接觸角儀(contact angle instrument)測量生醫高分子添加生醫陶瓷材料氫氧基磷灰石(HA; hydroxyapatite)與否,對親、疏水性增加的改變。實驗的第二部份,模擬以聚乳酸爲材料,仿製鼻整型常用之L型矽膠(silicone)支架:利用電腦繪圖軟體Pro/Engineering和Solidworks繪出L型矽膠支架的幾何圖形,匯入模流分析(Moldflow analysis),製作澆道(sprue),利用4個成形參數和田口法(Taguchi Method)找出最佳化的射出參數。 結果:本研究製作的生物多孔支架,經掃描式電子顯微鏡觀察顯示孔徑爲252-500μm,且孔洞分佈和孔連接性佳。生物支架孔隙率可達到90%以上。聚乳酸的平均接觸角爲725°,添加氫氧基磷灰石後增加至79.0°,增加了疏水性質:聚甘醇酸平均接觸角爲89.4°,添加氫氧基磷灰石後卻降低至71.8°,增加了親水性質。模擬射出成形過程,可在2.8秒時完整的充填完畢,無短射問題。充填過程中的溫度分佈大致在攝氏189~205度左右,溫差大致在攝氏20度。速度分佈均勻,無不均勻流速產生。依田口法得到的九組數據,找出L型支架射出成型最適合的最小翹曲量爲0.17mm。 結論:本研究以生醫高分子材料(聚乳酸和聚甘醇酸)製作的生物多孔支架,在孔徑分布、大小與孔隙率部份可依指定要求完全掌控。根據接觸角實驗,得到理想支架應具有的良好親水性,適合未來在支架內培養細胞。另外,此研究也完成了以聚乳酸爲村料的射出模擬,得到了最適合射出成形的參數,找到最小的支架翹曲量;模擬過程在充填時間、溫度分布及速度分布方面皆非常良好。適合作爲未來製作模具的參考。

並列摘要


BACKGROUND: The aim of this research combines the solvent casting/particulate leaching method with Moldflow analysis to analyze the L-type nasal scaffold with PLA (polylactic acid) and PLGA (polylactide-co-glycolide). METHODS: This research is divided into two parts: First, it takes the solvent casting/particulate leaching method slicing 2-3 mm biomedical porous scaffold, which is made from biomedical polymer material (PLA and PLGA), and observes its connection and the distribution of the apertures through the scanning electronic microscope (SEM). We use the Mercury Porosimetry to measure the porosity of the porous scaffold. This research uses the contact angle instrument to measure the hydrophobic and hydrophilic whether the biomedical polymer was added with hydroxyapatite or not. The second part of this research is to simulate L-type nasal scaffold, which is made of PLA. The geometry is constructed in computer aided design program (Solidworks, Pro/E) and then imported to Moldflow analysis. This Moldflow analysis has four processing parameters and uses Taguchi method to find the optimum processing parameters. RESULTS: In this work, we observe the pore size is 252-500 μm by scanning electron microscope, and the distribution of the pore, pore interconnectivity is good. The porosity is more than 90%. The average value of contact angle of PLA is 72.5°. If the experiment adds hydroxyapatite, the contact angle increases to 79.0°. That can increase the hydrophobic property. The average value of contact angle of PLGA is 89.4°. If the experiment adds the hydroxyapatite, the contact angle decreases to 71.8°. That can increase the hydrophilic property. In simulation of injection molding process, we can get that the filling time of injection molding is 2.8s, and no short shot occurs. The distribution of temperature is 189~205℃. The difference of temperature is about 20℃. We can get the suitable parameters in L-type scaffold and find the minimum of deflections from the Taguchi method. CONCLUSIONS: The distribution of the apertures, size and porosity of biomedical porous scaffold, which is made of biomedical polymer material, are under controlled accorded to the designated requirement. According to the contact angle experiment, the idea scaffold should have good hydrophilic and it suits to cultivate the required cells in the future. Besides, this experiment also accomplishes the simulation on injection molding, which uses PLA as the material, to gain the most appropriate parameter for injection molding and found the smallest deflection of the scaffold. The filling time, distribution of the temperature and the distribution of the speed are very good during the simulation and it is proper to take as the mold making reference in the future.

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