Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; Department of Physics, Northeastern University, Boston, MA, USA; Department of Microsystems Engineering and Cluster of Excellence livMatS@FIT, University of Freiburg, Freiburg, Germany.
J Mech Behav Biomed Mater. 2023 Aug;144:105897. doi: 10.1016/j.jmbbm.2023.105897. Epub 2023 May 11.
Tensile properties of directionally freeze-cast biopolymer scaffolds are rarely reported, even though they are of interest from a fundamental science perspective and critical in applications such as scaffolds for the regeneration of nerves or when used as ureteral stents. The focus of this study is on collagen scaffolds freeze-cast with two different applied cooling rates (10 °C/min and 1 °C/min) in two freezing directions (longitudinal and radial). Reported are the results of a systematic structural characterization of dry scaffolds by scanning electron microscopy and the mechanical characterization in tension of both dry and fully hydrated scaffolds. Systematic structure-property-processing correlations are obtained for a comparison of the tensile performance of longitudinally and radially freeze-cast collagen scaffolds with their performance in compression. Collated, the correlations, obtained both in tension in this study and in compression for collagen and chitosan in two earlier reports, not only enable the custom-design of freeze-cast biopolymer scaffolds for biomedical applications but also provide new insights into similarities and differences of scaffold and cell-wall structure formation during the directional solidification of "smooth" and "fibrillar" biopolymers.
定向冷冻铸造生物聚合物支架的拉伸性能很少有报道，尽管从基础科学的角度来看它们很有趣，并且在神经再生支架或用作输尿管支架等应用中至关重要。本研究的重点是研究两种不同冷却速率（10°C/min 和 1°C/min）和两种冷冻方向（纵向和径向）下冷冻铸造的胶原支架。通过扫描电子显微镜对干燥支架进行了系统的结构表征，并对干燥和完全水合支架进行了拉伸力学性能测试，报道了相关结果。对纵向和径向冷冻铸造胶原支架的拉伸性能与其压缩性能进行了比较，得出了系统的结构-性能-加工相关性。综合本研究中的拉伸性能以及之前两项研究中胶原和壳聚糖的压缩性能得到的相关性，不仅能够为生物医学应用定制设计冷冻铸造生物聚合物支架，还为“光滑”和“纤维状”生物聚合物定向凝固过程中支架和细胞壁结构形成的相似性和差异性提供了新的见解。
