School of Materials Science and Engineering, Nanyang Technological University (NTU), Singapore 639798.
Nanoscale. 2017 Sep 14;9(35):12908-12915. doi: 10.1039/c7nr02527k.
Stiff fibers are used as reinforcing phases in a wide range of high-performance composite materials. Silk is one of the most widely studied bio-fibers, but alternative materials with specific advantages are also being explored. Among these, native hagfish (Eptatretus stoutii) slime thread is an attractive protein-based polymer. These threads consist of coiled-coil intermediate filaments (IFs) as nano-scale building blocks, which can be transformed into extended β-sheet-containing chains upon draw-processing, resulting in fibers with impressive mechanical performance. Here, we report artificial hagfish threads produced by recombinant protein expression, which were subsequently self-assembled into coiled-coil nanofilaments, concentrated, and processed into β-sheet-rich fibers by a "picking-up" method. These artificial fibers experienced mechanical performance enhancement during draw-processing. We exploited the lysine content to covalently cross-link the draw-processed fibers and obtained moduli values (E) in tension as high as ∼20 GPa, which is stiffer than most reported artificial proteinaceous materials.
刚性纤维被广泛用作各种高性能复合材料的增强相。丝是研究最多的生物纤维之一，但也在探索具有特定优势的替代材料。其中，天然盲鳗（Eptatretus stoutii）黏液线是一种有吸引力的基于蛋白质的聚合物。这些线由卷曲螺旋中间纤维 (IF) 作为纳米级构建块组成，在拉伸处理过程中可以转化为扩展的β-折叠链，从而形成具有令人印象深刻的机械性能的纤维。在这里，我们报告了通过重组蛋白表达生产的人工盲鳗线，然后通过“拾取”方法将其自组装成卷曲螺旋纳米纤维、浓缩，并加工成富含β-折叠的纤维。这些人工纤维在拉伸处理过程中经历了机械性能的增强。我们利用赖氨酸含量使拉伸处理后的纤维发生共价交联，获得了高达约 20 GPa 的拉伸模量 (E) 值，比大多数报道的人工蛋白质材料都要硬。
