波浪狀電紡絲結構的機械性質與其對韌帶細胞的影響

在韌帶中膠原蛋白纖維呈現波浪狀的平行結構，而此種波浪狀結構帶給韌帶良好的活動性但卻又能保護關節避免脫臼。先前研究指出當韌帶細胞在有平行的電紡材料上會有較好的細胞外間質分泌。所以為了模擬真正韌帶中的環境，我們的實驗主要是探討平行與波浪狀電紡絲結構的機械性質上有什麼不同，以及細胞在此種支架上會有什麼樣的反應及表現，最後加入機械刺激後會帶給細胞什麼樣的影響。我們利用高分子聚合物玻璃轉移溫度(T g )的這項特性，加熱聚乳酸超過其 T g 值，使平行纖維變形而形成波浪形態的電紡絲，如此產生的纖維結構與韌帶的機械性質較為接近。此外細胞細胞型態在波浪狀電紡絲上也與平行電紡絲有相當大的不同，細胞及細胞骨架皆沿著纖維的走向做波浪狀的延展，但在平行電紡絲中細胞核型態皆呈現較細長且有明顯的張力絲(stress fiber)的生成。細胞在波浪狀電紡絲中 tenascin-C 與膠原帶白表現量明顯高於平行電紡絲。經由拉伸刺激之後，在波浪狀電紡絲上的細胞型態有著明顯的改變，且膠原蛋白的表現量也有明顯上升的趨勢。這說明了波浪狀電紡絲結構會影響細胞型態，且經由拉伸刺激波浪狀的纖維會帶給細胞不同的刺激進而促進細胞有良好的表現。

關鍵字

電紡絲；細胞；機械刺激；基因表現

並列摘要

Native ligament tissue is composed with aligned-wavy collagen fiber, and the wavy structure is believed to provide ligament with mechanical properties to support joint movement while preventing dislocation. Previous studies demonstrate that cells seeded on aligned electrospun fiber had higher extracellular matrix synthesis. Thus, The aim of this study is to investigate the effects of biomimetic wavy electrospun fiber scaffolds on material properties and cell physiology. We also examined the effects of mechanical stimulation on phenotypic expression.. We successfully fabricated aligned wavy fiber scaffold by heating straight electrospun PLLA polymers over its glass transition temperature (Tg). Our results show that the wavy fiber exhibit nonlinear mechanical properties more similar to those of ligament compared with straight fibers. Furthermore, cell morphology on wavy fiber is significantly different from the straight fibers. The cytoskeleton elongates with the wavy fiber, suppressing stress fiber formation, Comparing with the straight fiber group, nucleus shape on wavy fibers has smaller aspect ratio. Fiber morphology also affects cells phenotype. The wavy fiber substrate significantly increases collagen type I, type III and tenascin-C gene expression. After dynamic loading, gene expression of collagen type I and type III increased significantly. In summary, the wavy fiber provides a biomimetic substrate for ligament fibroblasts that will result in enhanced phenotypic gene expression

並列關鍵字

electrospinning ； cell ； mechanical stimulation ； gene expression

參考文獻

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2. Murray, M.M., Current status and potential of primary ACL repair. Clin Sports Med, 2009. 28(1): p. 51-61.

3. Lee, C.H., et al., Nanofiber alignment and direction of mechanical strain affect the ECM production of human ACL fibroblast. Biomaterials, 2005. 26(11): p. 1261-70.

4. Amiel, D.B., E.; Akeson, W., Ligament structure, chemistry and physiology. In Knee Ligaments: Structure, Function, Injury and Repair, 1990.

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波浪狀電紡絲結構的機械性質與其對韌帶細胞的影響

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