Allen Alicia C B, Barone Elissa, Crosby Cody O Keefe, Suggs Laura J, Zoldan Janet
Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
Biomater Sci. 2017 Jul 25;5(8):1661-1669. doi: 10.1039/c7bm00324b.
Cell alignment in muscle, nervous tissue, and cartilage is requisite for proper tissue function; however, cell sheeting techniques using the thermosensitive polymer poly(N-isopropyl acrylamide) (PNIPAAm) can only produce anisotropic cell sheets with delicate and resource-intensive modifications. We hypothesized that electrospinning, a relatively simple and inexpensive technique to generate aligned polymer fibers, could be used to fabricate anisotropic PNIPAAm and poly(caprolactone) (PCL) blended surfaces that both support cell viability and permit cell sheet detachment via PNIPAAm dissolution. Aligned electrospun PNIPAAm/PCL fibers (0%, 25%, 50%, 75%, 90%, and 100% PNIPAAm) were electrospun and characterized. Fibers ranged in diameter from 1-3 μm, and all fibers had an orientation index greater than 0.65. Fourier transform infrared spectroscopy was used to confirm the relative content of PNIPAAm and PCL. For advancing water contact angle and mass loss studies, only high PNIPAAm-content fibers (75% and greater) exhibited, temperature-dependent properties like 100% PNIPAAm fibers, whereas 25% and 50% PNIPAAm fibers behaved similarly to PCL-only fibers. 3T3 fibroblasts seeded on all PNIPAAm/PCL fibers had high cell viability and spreading except for the 100% PNIPAAm fibers. Cell sheet detachment by incubation with cold medium was successful only for 90% PNIPAAm fibers, which had a sufficient amount of PCL to allow cell attachment and spreading but not enough to prevent detachment upon PNIPAAm dissolution. This study demonstrates the feasibility of using anisotropic electrospun PNIPAAm/PCL fibers to generate aligned cell sheets that can potentially better recapitulate anisotropic architecture to achieve proper tissue function.
细胞在肌肉、神经组织和软骨中的排列对于组织的正常功能是必不可少的；然而，使用热敏聚合物聚（N-异丙基丙烯酰胺）（PNIPAAm）的细胞片技术只能通过精细且资源密集型的修饰来生产各向异性的细胞片。我们推测，静电纺丝作为一种相对简单且廉价的制备排列聚合物纤维的技术，可用于制造各向异性的PNIPAAm和聚己内酯（PCL）共混表面，该表面既能支持细胞活力，又能通过PNIPAAm溶解实现细胞片的脱离。对排列的静电纺PNIPAAm/PCL纤维（PNIPAAm含量为0%、25%、50%、75%、90%和100%）进行了静电纺丝和表征。纤维直径范围为1 - 3μm，所有纤维的取向指数均大于0.65。采用傅里叶变换红外光谱法确认PNIPAAm和PCL的相对含量。对于前进接触角和质量损失研究，只有高PNIPAAm含量的纤维（75%及以上）表现出与100% PNIPAAm纤维类似的温度依赖性特性，而25%和50% PNIPAAm纤维的行为与仅PCL纤维相似。接种在所有PNIPAAm/PCL纤维上的3T3成纤维细胞具有较高的细胞活力和铺展性，但100% PNIPAAm纤维除外。仅90% PNIPAAm纤维通过与冷培养基孵育成功实现了细胞片脱离，该纤维含有足够量的PCL以允许细胞附着和铺展，但又不足以阻止PNIPAAm溶解时的细胞片脱离。本研究证明了使用各向异性的静电纺PNIPAAm/PCL纤维来生成排列细胞片的可行性，这种细胞片可能能够更好地重现各向异性结构以实现适当的组织功能。
