Naghilou Aida, Pöttschacher Lena, Millesi Flavia, Mann Anda, Supper Paul, Semmler Lorenz, Weiss Tamara, Backus Ellen H G, Radtke Christine
Research Laboratory of the Division of Plastic and Reconstructive Surgery, Department of Surgery, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Austria.
Department of Physical Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria.
Mater Sci Eng C Mater Biol Appl. 2020 Nov;116:111219. doi: 10.1016/j.msec.2020.111219. Epub 2020 Jun 20.
The successful reconstruction of supercritical peripheral nerve injuries remains a major challenge in modern medicine. Progress in tissue engineering has enabled the development of nerve guidance conduits as an alternative to autologous nerve transplantation and the enrichment of conduits with fibrous materials or hydrogels has shown great potential in bridging nerve defects. The application of the dragline silk of spider genus Nephila as a filament for nerve guidance conduits has led to promising results. However, the use of spider silk has been phenomenological so far and the reasons for its success are still not identified. This renders a targeted tuning of synthetic fibrous luminal fillings such as recombinant silk out of reach. In this work the existing research was extended and in addition to dragline, the cocoon silk of Nephila edulis, as well as the connecting and attaching silk of Avicularia avicularia were investigated. Scanning electron microscopy revealed a difference in size and morphology of the spider silks. However, in vitro experiments indicated that Schwann cells adhere to the four fibers, independent of these two attributes. Raman spectroscopy in native state and aqueous environment demonstrated similar secondary protein structures for dragline, cocoon, and connecting silk. In contrast, the attaching silk showed a significant lower conformation of β-sheets, crucial for the stiffness of the silk. This was in line with the in vitro experiments, where the flexible attaching silk fibers adhered to each other when placed in liquid. This resulted in their inability to guide Schwann cells, leading to the generation of cell agglomerations. This direct comparison demonstrated the crucial role of β-sheets conformation for the guidance properties of natural spider silk, providing essential insights into the necessary material properties for the integration of fibrous luminal fillings in nerve guidance conduits.
超临界周围神经损伤的成功修复仍是现代医学中的一项重大挑战。组织工程学的进展使神经引导导管得以发展，作为自体神经移植的替代方法，用纤维材料或水凝胶填充导管在桥接神经缺损方面显示出巨大潜力。将黄金圆蛛的拖牵丝用作神经引导导管的细丝已取得了令人鼓舞的成果。然而，迄今为止，蜘蛛丝的使用一直停留在现象学层面，其成功的原因仍未明确。这使得有针对性地调整合成纤维管腔内填充物（如重组丝）变得遥不可及。在这项工作中，我们扩展了现有研究，除了拖牵丝外，还研究了马来黄金圆蛛的茧丝以及华丽雨林蛛的连接丝和附着丝。扫描电子显微镜显示了蜘蛛丝在大小和形态上的差异。然而，体外实验表明，雪旺细胞能附着在这四种丝上，与这两个特性无关。在天然状态和水环境下的拉曼光谱表明，拖牵丝、茧丝和连接丝具有相似的二级蛋白质结构。相比之下，附着丝的β折叠构象明显较低，但β折叠对丝的硬度至关重要。这与体外实验结果一致，在体外实验中，柔性的附着丝纤维在液体中放置时会相互粘连。这导致它们无法引导雪旺细胞，从而形成细胞团聚。这种直接比较证明了β折叠构象对天然蜘蛛丝引导特性的关键作用，为纤维管腔内填充物在神经引导导管中的整合所需的材料特性提供了重要见解。
