以電氣紡絲法製備具方向性纖維之管狀結構

Abstract

奈米纖維細胞生長支架結構近來被廣泛應用在組織工程上，因為其同時具有多孔性的特質及較高的面積-體積比，並擁有較多樣性的表面結構特徵，這些特性都有利於細胞的附著、遷移和增殖。纖維支架結構的性質會隨著纖維尺寸的大小、排列方式、材料等而改變，因此近幾年對於透過電氣紡絲方式製作組織工程結構材料方面的研究數量有明顯上升的趨勢。經由電氣紡絲法所製備出的奈米級結構，大概可以分為兩種類型，即有順序性的與雜亂無順序性的結構。傳統電氣紡絲法所製備出來的支架結構，通常都是由高分子或天然聚合物纖維絲以亂數重疊排列，形成薄膜或其他的立體狀結構。而由具有特定方向性的纖維所組成的結構，會具有較佳的機械強度，且也具有較佳的細胞相容性。 目前已有部份學者針對製備具方向性排列之結構，提出數種可行之方法，但受限於製程上的限制，並無法在小管徑的管狀結構上，製作出表面形態具方向性的纖維，故本研究將利用電氣紡絲函工技術將聚乳酸與聚乙二醇進行混合射出函工，並結合單軸心旋轉及外函兩平行接地導體，來改良電氣紡絲收集纖維絲的方式，製作出纖維具方向性排列的管狀結構。實驗結果顯示此方法可有效製造出方向性一致的纖維結構，亦可在較低旋轉轉速下製備小管徑的管狀結構，如此製造出具較佳機械強度及生物組織相仿性的管狀纖維結構，可以提高在心血管組織工程領域上的應用。

Scaffolds with nanofibers are being applied in tissue engineering due to its high porosities and surface area-to-volume ratios as well as a wide variety of topographical features to encourage cellular adhesion, migration, and proliferation. Furthermore, the physical properties can be easily altered by changing the size, arrangement and material of fiber. Thus, tissue engineering scaffold research using the electrospinning technique has been increased. The nanotopographies features created by electrospinning can be separated into two main categories: unordered topographies and ordered topographies. Scaffolds fabricated by electrospinning, the fibers are typically randomly oriented in the form of nonwoven mats. The structure with well-ordered fibers not only can improve mechanical properties but also has better biocompatibility.

There have been a few approaches to improve the orderliness of electrospun fibers, but it is difficult to fabricate tubular structure with aligned architecture. The polymers we used are polylactic acid (PLA) and poly(ethylene oxide) (PEO). By combining mandrel and two parallel conductors, and using the rotating mandrel as ground target to collect fibers, we achieved to fabricate small diameter tubular structures with aligned nanofibers at lower tangential speed. The tubular structure with aligned topography which mimics the native artery and with better mechanical properties can be applied in blood vessel engineering.