Department of Biomedical and Chemical Engineering, 121 Link Hall, Syracuse University, Syracuse, NY 13244, USA; Syracuse Biomaterials Institute, 318 Bowne Hall, Syracuse University, Syracuse, NY 13244, USA.
Acta Biomater. 2013 Nov;9(11):8790-801. doi: 10.1016/j.actbio.2013.06.043. Epub 2013 Jul 9.
Tissue engineering scaffolds have traditionally been static physical structures poorly suited to mimicking the complex dynamic behavior of in vivo microenvironments. Here we present a thermoresponsive scaffold that can be programmed to change macroscopic shape and microscopic architecture during cell culture. The scaffold, which was prepared by electrospinning a shape memory polymer (SMP), was used to test the hypothesis that a shape-memory-actuated change in scaffold fiber alignment could be used to control the behavior of attached and viable cells. To test this hypothesis, we stretched an SMP scaffold of randomly oriented fibers and fixed the scaffold in a temporary but stable elongated shape in which fibers were aligned by the strain. Following seeding and culture of human adipose-derived stem cells on the strain-aligned scaffold, the scaffold was triggered to transition back to its initial shape and random fiber orientation via shape memory actuation using a cytocompatible temperature increase. We found that cells preferentially aligned along the fiber direction of the strain-aligned scaffold before shape memory actuation. After shape memory actuation, cells remained attached and viable but lost preferential alignment. These results demonstrate that shape-memory-actuated changes in scaffold fiber alignment can be achieved with attached and viable cells and can control cell morphological behavior. The incorporation of shape memory into cytocompatible scaffolds is anticipated to facilitate the development, delivery and functionality of tissue engineering scaffolds and the in vitro and in vivo study and application of mechanobiology.
组织工程支架传统上是静态的物理结构，不太适合模拟体内微环境的复杂动态行为。在这里，我们提出了一种热响应支架，它可以在细胞培养过程中编程改变宏观形状和微观结构。该支架是通过静电纺丝形状记忆聚合物（SMP）制备的，用于测试以下假设：支架纤维排列的形状记忆驱动变化可用于控制附着和存活细胞的行为。为了验证这一假设，我们拉伸了一个随机取向纤维的 SMP 支架，并将支架固定在一个临时但稳定的伸长形状中，其中纤维通过应变排列。在将人脂肪来源干细胞接种和培养在应变排列的支架上后，通过使用细胞相容性温度升高进行形状记忆驱动，支架触发回退到其初始形状和随机纤维取向。我们发现，细胞在形状记忆驱动之前优先沿应变排列的支架纤维方向排列。在形状记忆驱动之后，细胞仍然附着并存活，但失去了优先排列。这些结果表明，附着和存活的细胞可以实现支架纤维排列的形状记忆驱动变化，并可以控制细胞形态行为。将形状记忆纳入细胞相容支架中，预计将促进组织工程支架的开发、交付和功能，以及体外和体内研究和应用机械生物学。
