Jordan Alex M, Kim Si-Eun, Van de Voorde Kristen, Pokorski Jonathan K, Korley LaShanda T J
Center for Layered Polymeric Systems, Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7202, United States.
ACS Biomater Sci Eng. 2017 Aug 14;3(8):1869-1879. doi: 10.1021/acsbiomaterials.7b00229. Epub 2017 Jun 7.
Hydrogels are an important class of biomaterials, but are inherently weak; to overcome this challenge, we report an in situ manufacturing technique to fabricate mechanically robust, fiber-reinforced poly(ethylene oxide) (PEO) hydrogels. Here, a covalent PEO cross-linking scheme was implemented to derive poly(ε-caprolactone) (PCL) fiber reinforced PEO hydrogels from multilayer coextruded PEO/PCL matrix/fiber composites. By varying PCL fiber loading between ∼0.1 vol % and ∼7.8 vol %, hydrogel stiffness was tailored from 0.69 ± 0.04 MPa to 1.94 ± 0.21 MPa. The influence of PCL chain orientation and enhanced mechanics via uniaxial drawing of PCL/PEO composites revealed a further 225% increase in hydrogel stiffness. To further highlight the robust nature of this manufacturing process, we also derived rigid poly(l-lactic acid) (PLLA) fiber-reinforced PEO hydrogels with a stiffness of 8.71 ± 0.21 MPa. Fibroblast cells were injected into the hydrogel volume, which displayed excellent ingrowth, adhesion, and proliferation throughout the fiber reinforced hydrogels. Finally, the range of mechanical properties obtained with fiber-reinforced hydrogels directed differentiation pathways of MC3T3-E1 cells into osteoblasts. This innovative manufacturing approach to achieve randomly aligned, well-distributed, micrometer-scale fibers within a hydrogel matrix with tunable mechanical properties represents a significant avenue of pursuit not only for load-bearing hydrogel applications, but also targeted cellular differentiation.
水凝胶是一类重要的生物材料，但本质上较为脆弱；为克服这一挑战，我们报告了一种原位制造技术，用于制造机械性能强大的纤维增强聚环氧乙烷（PEO）水凝胶。在此，实施了一种共价PEO交联方案，以从多层共挤出的PEO/聚己内酯（PCL）基质/纤维复合材料中获得PCL纤维增强的PEO水凝胶。通过将PCL纤维负载量在约0.1体积%至约7.8体积%之间变化，水凝胶的刚度从0.69±0.04兆帕调整到1.94±0.21兆帕。PCL链取向以及通过PCL/PEO复合材料的单轴拉伸增强力学性能的影响表明，水凝胶刚度进一步提高了225%。为进一步突出这种制造工艺的强大性能，我们还制备了刚度为8.71±0.21兆帕的刚性聚左旋乳酸（PLLA）纤维增强PEO水凝胶。将成纤维细胞注入水凝胶中，细胞在整个纤维增强水凝胶中呈现出良好的向内生长、黏附及增殖。最后，纤维增强水凝胶所获得的一系列力学性能引导了MC3T3-E1细胞向成骨细胞的分化途径。这种创新的制造方法能够在具有可调力学性能的水凝胶基质中实现随机排列、分布均匀的微米级纤维，不仅对于承重水凝胶应用，而且对于靶向细胞分化而言，都是一个重要的追求方向。
