| 摘要: | 神經再生醫學中，理想的神經導管支架(Scaffold)需具備方向導引及多孔滲透特性。方向性導引可使軸突(Axon)往斷端方向生長、多孔洞表面的特性可提供細胞貼附、生長及細胞養分與代謝物交換之管道，幫助神經纖維再生，達到神經修復的目的。本研究目的以靜電紡絲(Electrospinning)技術製備高順向微孔中空纖維膜，應用於神經再生導管(Nerve Guide Conduit, NGC)。本實驗以聚乙二醇(Polyethylene glycol, PEG)為製孔劑(Porogen)與聚乳酸(Polylactic acid, PLA)混合配成PLA/PEG溶液，將PLA/PEG混合溶液透過同軸模頭(Co-axial spinneret)紡出纖維於旋轉收集器收集，藉由調控不同紡絲參數製成高順向纖維膜，隨後將高順向纖維膜經由水洗，將芯層結構與製孔劑溶解洗出，即獲得高順向微孔化中空纖維膜。控制不同聚乳酸與製孔劑的配比，形成不同孔洞尺寸、孔隙率並具滲透特性的微孔中空纖維膜。樣品分別進行電子顯微鏡、分光測色儀、質地分析儀、生物相容性評估，依序分析樣品孔洞尺寸、滲透量、機械性質，生物相容評估則是觀察細胞存活性及觀察細胞排列。結果顯示，隨著製孔劑之含量增加而纖維表面孔隙率與微孔洞尺寸也隨之提升，高順向微孔化中空纖維尺寸長約30~40 µm、寬約10~15 µm、管壁厚度約2~3 µm，孔隙率從5%至18%，微孔洞尺寸分佈0.05~0.5 µm。本實驗系列樣品經由TGA測試，當製孔劑含量較少時，仍有殘餘在管壁中無法被完全洗除。拉伸測試中，隨著製孔劑含量增加，纖維表面孔隙率也隨之增加，導致結構上的缺陷，而影響纖維拉伸強度下降。滲透測試得知，透過水洗去除製孔劑製備出微孔洞利於滲透率的增加，隨著孔隙率增加滲透量也隨之提升，而Inflow的滲透速率大於Outflow。利用SEM觀察細胞貼附於中空纖維表面的形態，顯示高順向微孔化中空纖維薄膜可引導C6神經膠細胞向纖維方向排列，且微孔洞表面可增加細胞貼附量。
利用靜電紡絲技術製備高順向排列中空纖維膜，藉由調控不同製孔劑比例，得到不同的孔隙率分佈與滲透特性行為的中空纖維膜，其高順向結構與滲透特性可應用於神經或血管再生支架。
In neuro-regenerative medicine, the ideal nerve guide conduit (NGC) calls for directional guidance and porosity for permeation. Directional guidance of conduit can lead axonal growth toward proper location, while porous structure of conduit can, not only, enhance cell attachment, but also provide pathway for exchange of nutrients and metabolites. The aim of this study was to develop a highly aligned, microporous, hollow poly-L-lactic acid (PLA) fibrous membrane (in macro scale) and a microtube array,( MTA, in micro scale) as advanced NGC. MTA was prepared by co-axial electrospinning of PLA and polyethylene glycol (PEG) solutions, with PLA as the shell, and PEG as the core/porogen. After electrospinning, the inner core and porogen were washed off to make hollow fibers with microporous wall. The morphological study revealed the rectangular shape of the MTA cross section with dimensions of 30~40 µm in length, 10~15 µm in width, and 2~3 µm in wall thickness. By increasing the amount of porogen added, the wall porosity of the hollow fiber increased from 5 to 18%, with pore size in the range of 50~500 nm. TGA data showed that the porogen was difficult to completely wash off, especially with low PEG content. The mechanical properties of the MTA decreased with an increase in porogen content. The permeation of both BSA and glucose increased with an increase in wall porosity. Inflow permeation was found to be higher than that of outflow, suggesting an asymmetric structure of the microtube wall, which was echoed by SEM images. In summary, coaxial spinneret and rotating collector were used to produce a novel MTA via electrospinning. By leaching-out the porogen, MTA was made micro-porous. The permeation rate increased with porosity, (porogen content). The unique directional guidance, more effective surface, and improved permeation abilities of MTA are powerful elements for an advanced NGC. |
