幹細胞於彈性電紡纖維上之分化能力

Abstract

本研究主要探討成球細胞與非成球細胞於不同纖維尺度之聚胺酯(polyurethane, PU)電紡膜上的細胞表現差異，之後進一步比較在相同尺度下之不同材料(聚胺酯及聚己內酯)和不同之薄膜加工方式(電紡膜及相轉換薄膜)，對於成球細胞分化能力之影響。其中三種不同纖維直徑(200-400 nm、600-800 nm及1.4-1.6 μm)之聚胺酯電紡膜的製備方式為結合高低沸點溶劑二甲基乙醯胺及三氟乙醇，於調整高分子溶液濃度、流速、電壓及接收距離下所得，而選用之細胞以人類骨髓間葉幹細胞(human bone marrow mesenchymal stem cells, hBMSC)為研究模式。由貼附增生及基因表現之結果可得知，於不同纖維尺度及不同親疏水性之聚胺酯電紡膜上，成球細胞不僅能穩定地維持貼附率，同時比非成球細胞具有更佳之軟硬骨分化能力，特別是在與細胞外基質結構相似之聚胺酯奈米電紡絲上(200-400 nm)。至於比較成球細胞在相同纖維尺度之聚胺酯及聚己內酯電紡膜上之分化能力，基因表現結果得知幹細胞於聚胺酯電紡膜上具有較佳之軟硬骨化能力，其中又以硬骨化之表現程度更為顯著。而在聚胺酯電紡膜及相轉換薄膜對於成球細胞硬骨化能力影響之部分，基因和蛋白質表現顯示幹細胞於聚胺酯相轉換薄膜上之硬骨化表現為最佳，不過由於其延展性過低而應用相對受到限制。因此，將hBMSC成球細胞結合聚胺酯電紡絲能具有較佳之軟硬骨組織工程上的應用潛力。

The behavior of human bone marrow derived mesenchymal stem cells (hBMSC) was evaluated on biodegradable polyurethane electrospun fibers with different diameter ranges (200-400 nm, 600-800 nm, and 1.4-1.6 μm). Cells were seeded on the fibrous membranes in the form of single dispersed cells or self-assembled spheroids. The effect of material elasticity was further elucidated by comparing cell behavior on polyurethane and poly(ε-caprolactone). Fibers were electrospun from polymer solutions in N,N-dimethylacetamide and 2,2,2-trifluoroethanol. Differentiation experiments showed that hBMSC spheroids seeded had greater differentiation capacities than single cells. Gene expression revealed that nanofibers of 200-400 nm diameters significantly promoted the osteogenic and chondrogenic differentitation of hBMSC spheroids than fibers of the other diameters. hBMSC also demonstrated significantly higher osteochondrogenic differentiation potential on polyurethane vs. poly(ε-caprolactone) electrospun fibers. hBMSC on polyurethane membranes fabricated by wet phase separation (WPS) showed more bone-related marker gene expression and matrix mineralization than electropsun fibers, but WPS membranes had limited elongation. We suggested that hBMSC spheroids seeded on electrospun fibers may be advantageous for cartilage and bone tissue engineering.