University of Tehran, School of Mechanical Engineering, College of Engineering, Tehran 1417935840, Islamic Republic of Iran.
National Cell Bank of Iran, Pasteur Institute of Iran, Tehran 1417935840, Iran.
ACS Biomater Sci Eng. 2021 Oct 11;7(10):4763-4778. doi: 10.1021/acsbiomaterials.1c00651. Epub 2021 Sep 13.
Not very far away, "tissue engineering" will become one of the most important branches of medical science for curing many types of diseases. This branch needs the cooperation of a wide range of sciences like medicine, chemistry, cellular biology, and genetic and mechanical engineering. Different parameters affect the final produced tissue, but the most important one is the quality and biocompatibility of the scaffold with the desired tissue which can provide the functionality of "native ECM" as well. The quality of the scaffold is directly dependent on its materials, design, and method of fabrication. As to the design and fabrication, there are two main categories: (a) random microporosity such as phase separation, electrospinning, and fused deposition modeling (3D printing) and (b) designed microporosity mostly achievable by stereo lithography and soft lithography. The method of fabrication implemented in this research is a novel method in soft lithography employing a type of "replica molding" with one pair of polydimethylsiloxane (PDMS) molds in contrast to traditional replica molding with just one single mold. In this operation, the solution of polycaprolactone in chloroform is initially prepared, and one droplet of the solution is placed between the molds while a preset pressure is applied to maintain the molds tightly together during the solidification of the polymer layer and vaporization of the solvent. Thus, a perfect warp and woof pattern is created. In this research, it has been approved that this is a feasible method for creating complex patterns and simple straight fiber patterns with different spacings and pore sizes. Cell attachment and migration was studied to find the optimum pore size. It was shown that the small pore size improves the cells' adhesion while reducing cell migration capability within the scaffold.
不远处，“组织工程”将成为医学科学治愈多种疾病的最重要分支之一。这个分支需要医学、化学、细胞生物学、遗传和机械工程等广泛的科学合作。不同的参数会影响最终产生的组织，但最重要的是支架与所需组织的质量和生物相容性，它可以提供“天然 ECM”的功能。支架的质量直接取决于其材料、设计和制造方法。至于设计和制造，有两种主要类型：(a) 随机微孔，如相分离、静电纺丝和熔融沉积成型（3D 打印）和 (b) 设计的微孔，主要通过立体光刻和软光刻实现。本研究中采用的制造方法是软光刻的一种新方法，使用一对聚二甲基硅氧烷 (PDMS) 模具进行复制模塑，而不是传统的仅使用一个模具进行复制模塑。在这个操作中，首先制备聚己内酯在氯仿中的溶液，将溶液的一滴放置在模具之间，同时施加预设压力，以在聚合物层固化和溶剂蒸发期间保持模具紧密贴合。因此，创建了一个完美的经纬图案。在这项研究中，已经证实这是一种创建复杂图案和不同间距和孔径的简单直纤维图案的可行方法。研究了细胞附着和迁移，以找到最佳孔径。结果表明，小孔径可以提高细胞的粘附力，同时降低细胞在支架内的迁移能力。
