The elaboration of scaffolds able to efficiently promote cell differentiation toward a given cell type remains challenging. Here, we engineered dense type I collagen threads with the aim of providing scaffolds with specific morphological and mechanical properties for C3H10T1/2 mesenchymal stem cells. Extrusion of pure collagen solutions at different concentrations (15, 30, and 60 mg/mL) in a PBS 5× buffer generated dense fibrillated collagen threads. For the two highest concentrations, threads displayed a core–shell structure with a marked fibril orientation of the outer layer along the longitudinal axis of the threads. Young’s modulus and ultimate tensile stress as high as 1 and 0.3 MPa, respectively, were obtained for the most concentrated collagen threads without addition of any cross-linkers. C3H10T1/2 cells oriented themselves with a mean angle of 15–24° with respect to the longitudinal axis of the threads. Cells penetrated the 30 mg/mL scaffolds but remained on the surface of the 60 mg/mL ones. After three weeks of culture, cells displayed strong expression of the tendon differentiation marker Tnmd, especially for the 30 mg/mL threads. These results suggest that both the morphological and mechanical characteristics of collagen threads are key factors in promoting C3H10T1/2 differentiation into tenocytes, offering promising levers to optimize tissue engineering scaffolds for tendon regeneration.

中文翻译：

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从高浓度溶液中挤出的核-壳纯胶原蛋白线可促进C3H10T1 / 2细胞的定殖和分化

能够有效促进细胞向给定细胞类型分化的支架的制备仍然具有挑战性。在这里，我们设计了密集的I型胶原蛋白线，旨在为C3H10T1 / 2间充质干细胞提供具有特定形态和机械特性的支架。在PBS 5x缓冲液中挤出不同浓度（15、30和60 mg / mL）的纯胶原蛋白溶液会产生致密的原纤化胶原蛋白线。对于两个最高浓度，线表现出核-壳结构，外层沿线的纵轴具有明显的原纤维取向。在不添加任何交联剂的情况下，对于最浓缩的胶原蛋白线，分别获得了高达1和0.3 MPa的杨氏模量和极限拉伸应力。C3H10T1 / 2细胞相对于螺纹的纵轴以15–24°的平均角度定向。细胞穿透了30 mg / mL的支架，但保留在60 mg / mL的支架表面。培养三周后，细胞显示出肌腱分化标记物Tnmd的强表达，特别是对于30 mg / mL的线。这些结果表明，胶原线的形态和机械特性都是促进C3H10T1 / 2向肌腱细胞分化的关键因素，为优化组织工程支架的腱再生提供了有希望的杠杆。细胞显示出肌腱分化标记物Tnmd的强表达，尤其是对于30 mg / mL的线。这些结果表明，胶原线的形态和机械特性都是促进C3H10T1 / 2向肌腱细胞分化的关键因素，为优化组织工程支架的腱再生提供了有希望的杠杆。细胞显示出肌腱分化标记物Tnmd的强表达，尤其是对于30 mg / mL的线。这些结果表明，胶原线的形态和机械特性都是促进C3H10T1 / 2向肌腱细胞分化的关键因素，为优化组织工程支架的腱再生提供了有希望的杠杆。