具有周向微槽结构管状血管支架制备及诱导平滑肌细胞的取向生长

Fabrication of a tubular vascular scaffold with circumferential microchannels to induce oriented growth of smooth muscle cells

背景:对小口径血管组织工程化而言,平滑肌细胞的周向排列要求彻底改变以前支架的简单多孔结构,代之以能够诱导血管平滑肌细胞三维周向取向和排列新型微观结构。目的:观察微槽结构对平滑肌细胞体外定向诱导的影响。方法:用静电纺丝、熔融纺丝并利用溶剂/非溶剂和热压的方式制得了具有两层管壁、外壁具有周向微沟槽结构的仿生管状血管支架,用胶原蛋白固定改性后,在其上种植人脐静脉血管平滑肌细胞。扫描电镜和荧光显微镜观察支架不同缠绕角度对平滑肌细胞定向诱导能力的影响。结果与结论:①选择比例为5∶95的氯仿/乙醇溶液,浸润时间为5s,可以使乳酸-羟基乙酸共聚物电纺纤维和乳酸-ε-己内酯共聚物熔纺纤维之间形成很好的粘连,形成支架。②通过碱降解使支架表面含有羧基,以1-(二甲基胺丙基)-3-乙基碳化二亚胺为缩合剂在支架表面接枝胶原。X射线光电子能谱证实了支架表面胶原大分子的存在。③当纤维之间的编织角度为30°即网孔尺寸适当时,细胞能在支架内部和表面大面积生长。④具有两层管壁结构的仿生管状血管支架具有良好的细胞相容性,其表面周向微槽结构对平滑肌细胞的取向排列具有明显的诱导作用。提示在电纺层外面再熔纺缠绕降解聚合物是制备管状仿生血管支架的可行方法。血管平滑肌细胞能沿着纤维暨微沟槽方向一致取向排列。

BACKGROUND： In vascular tissue engineering, scaffolds that can induce smooth muscle cells align and orientate in circumferential direction, but not simple porous scaffold, would be welcome. OBJECTIVE： To observe the effect of circumferential microchannels on the in vitro induction of smooth muscle cells. METHODS： Electrospinning, melt spinning, and solvent adhesion techniques were combined and the as-prepared scaffolds were further modified by grafting collagen for improving their biocompatibility. Scanning electron microscope and fluorescence microscope were selected to characterize the alignment of smooth muscle cells on these biomimetic scaffolds. RESULTS AND CONCLUSION： Mixture of chloroform/alcohol with volume ratio at 5：95 was used to bond the elextro spun poly（lactic-co-glycolic acid） fibers and melt spun poly（ε-caprolactone-co-lactic acid） fibers successfully toward creating a biomimetic vascular scaffold. The scaffold surface was first introducing active carboxylate group by alkali hydrolyzing and then coupling with collagen by using carbodiimide. When the weaving angle in the melt spinning was suitable （30°）, the pores of the scaffold could ensure the growth of smooth muscle cells on and in the scaffold homogenously. All the smooth muscle cells aligned along the microfibers and microchannels of the scaffolds, demonstrating that such novel type of scaffold had strong ability in inducing smooth muscle cells regenerating their microarchitecture in vivo. It is helpful in developing biomimetic tubular scaffold to induce blood vessel regeneration in vivo.