Liu Hailong, Jain Shubham, Ahlinder Astrid, Fuoco Tiziana, Gasser T Christian, Finne-Wistrand Anna
Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden.
Department of Engineering Mechanics, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden.
ACS Polym Au. 2021 Aug 12;1(2):107-122. doi: 10.1021/acspolymersau.1c00013. eCollection 2021 Oct 13.
Clinical results obtained when degradable polymer-based medical devices are used in breast reconstruction following mastectomy are promising. However, it remains challenging to develop a large scaffold structure capable of providing both sufficient external mechanical support and an internal cell-like environment to support breast tissue regeneration. We propose an internal-bra-like prototype to solve both challenges. The design combines a 3D-printed scaffold with knitted meshes and electrospun nanofibers and has properties suitable for both breast tissue regeneration and support of a silicone implant. Finite element analysis (FEA) was used to predict the macroscopic and microscopic stiffnesses of the proposed structure. The simulations show that introduction of the mesh leads to a macroscopic scaffold stiffness similar to the stiffness of breast tissue, and mechanical testing confirms that the introduction of more layers of mesh in the modular design results in a lower elastic modulus. The compressive modulus of the scaffold can be tailored within a range from hundreds of kPa to tens of kPa. Biaxial tensile testing reveals stiffening with increasing strain and indicates that rapid strain-induced softening occurs only within the first loading cycle. In addition, the microscopic local stiffness obtained from FEA simulations indicates that cells experience significant heterogeneous mechanical stimuli at different places in the scaffold and that the local mechanical stimulus generated by the strand surface is controlled by the elastic modulus of the polymer, rather than by the scaffold architecture. From experiments, it was observed that the addition of knitted mesh and an electrospun nanofiber layer to the scaffold significantly increased cell seeding efficiency, cell attachment, and proliferation compared to the 3D-printed scaffold alone. In summary, our results suggest that the proposed design strategy is promising for soft tissue engineering of scaffolds to assist breast reconstruction and regeneration.
在乳房切除术后使用基于可降解聚合物的医疗设备进行乳房重建所获得的临床结果很有前景。然而，开发一种能够提供足够的外部机械支撑和内部细胞样环境以支持乳房组织再生的大型支架结构仍然具有挑战性。我们提出了一种类似内部胸罩的原型来解决这两个挑战。该设计将3D打印支架与针织网和电纺纳米纤维相结合，具有适合乳房组织再生和支撑硅胶植入物的特性。使用有限元分析（FEA）来预测所提出结构的宏观和微观刚度。模拟结果表明，引入网导致宏观支架刚度与乳房组织的刚度相似，并且机械测试证实，在模块化设计中引入更多层网会导致弹性模量降低。支架的压缩模量可以在数百kPa到数十kPa的范围内定制。双轴拉伸测试表明，随着应变增加刚度增加，并表明快速应变诱导的软化仅在第一个加载周期内发生。此外，从FEA模拟获得的微观局部刚度表明，细胞在支架的不同位置经历显著的非均匀机械刺激，并且由股线表面产生的局部机械刺激由聚合物的弹性模量控制，而不是由支架结构控制。从实验中观察到，与单独的3D打印支架相比，向支架中添加针织网和电纺纳米纤维层显著提高了细胞接种效率、细胞附着和增殖。总之，我们的结果表明，所提出的设计策略对于用于辅助乳房重建和再生的支架软组织工程很有前景。
