神經導管接合術是利用顯微手術將神經兩斷端縫入生醫材料所製備之神經導管以橋接神經斷裂的兩端，神經可藉由軸突的再生而重新連接缺口兩端的神經使功能恢復，導管可減少神經拉扯時造成的張力並引導軸突的再生，亦可承載神經生長因子促進神經再生，此外，也可以將阻礙神經再生的細胞及其分泌物阻擋在管外。本研究將以聚乳酸、聚乳酸-聚甘醇酸共聚合物（75：25）、聚乳酸-聚甘醇酸共聚合物（50：50）做為研究材料，以檸檬酸誘發碳酸氫銨發泡之氣泡成型法製作具有相連通孔隙之高分子薄膜，再將高分子薄膜捲製成特殊多層的導管，製作具有多層孔隙之新型神經再生導管，以電子能譜化學分析及減弱式全反射-傅立葉轉換紅外線光譜分析進行成份分析及化學元素測定；以電荷耦合元件攝影機、掃瞄式電子顯微鏡進行多層孔隙型神經導管巨觀及微觀形態結構觀察；以示差掃瞄熱量量測分析玻璃轉換溫度、奈米三維量測彈性模數及硬度；以及進行降解性質測定，並以掃瞄式電子顯微鏡進行降解後之導管微觀結構形態觀察。實驗結果顯示：聚乳酸、聚乳酸-聚甘醇酸共聚物（75：25）、聚乳酸-聚甘醇酸共聚物（50：50）三種材料經檸檬酸誘發碳酸氫銨發泡之氣泡成型法製程並不造成碳酸氫銨之殘留。聚乳酸-聚甘醇酸共聚物（50：50）的玻璃轉換溫度低於人體正常體溫，故降解28天後，導管的孔隙已融合成為緻密的表面，且於降解56天後完全降解；聚乳酸-聚甘醇酸共聚物（75：25）降解速率較慢，且降解56天後，孔隙略有融合的現象；而聚乳酸經檸檬酸誘發碳酸氫銨發泡再以捲製成型，可製造出具有較高的孔隙率及相連通的開孔結構之多層孔隙型神經導管，且降解56天後，仍可維持良好的孔隙率以維持導管的通透性質。

　　Nerve bridging is suture a biomaterial-made conduit and to overpass the damaged nerve end to end with microsurgery. Peripheral nerve could be bridged between the proximal nerve and the distal stump to restore the function. Nerve conduits could eliminate tension at the healing site and induce the regeneration of axons. Nerve conduits also could permit neurobiological recovery to enhance neural regeneration and stop cells and their secretions from obstructing neural regeneration. In this study, we used poly L-latcide (PLLA), poly DL-latcide-co-glycolide 75:25 (PLGA7525) and poly DL-latcide-co-glycolide 50:50 (PLGA5050) during citric acid inducing ammonium bicarbonate gas forming process to form porous polymer film, and rolled the porous polymer film to make nerve conduits with pores and multi-layered. Electron Spectroscopy for Chemical Analyzer (ESCA) and Attenuated Total Reflectance – Fourier-Transform Infrared Spectrometer (ATR-FTIR) were employed for determining elements’ functionabilities and chemical compounds. Charge Coupled Device camera (CCD camera) and Scanning Electron Microscope (SEM) were employed for macroscopic and microscopic morphologies and structural observation. Differential Scanning Calorimetry (DSC) was employed for measuring glass-transition temperature (Tg). Nano-indentation system was employed for measuring elastic modulus and hardness. Biodegradation and water absorption ratios were measured to analyze their chemical properties and SEM was employed for microscopic morphology of the tested nerve conduit. Experiment results demonstrated that during citric acid inducing ammonium bicarbonate gas forming process, no salts (ammonium bicarbonate) remained, while Tg of PLGA5050 was lower than human body temperature. The porous structures of PLGA5050 conduit were dissolved into a condensed morphology after 28 testing days, while the material was completely degraded after 56 testing days. The degradation of PLGA7525 conduit was relatively slow, while the porous structures slightly changed their shapes after 56 testing days. Using citric acid inducing ammonium bicarbonate gas forming and unique rolling process, PLLA is relatively suitable to make multi-layered nerve conduits, which provide highly porous structures with many round openings. In addition, the porous structures with channeling characteristic can be preserved to 56 testing days.

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