Department of Agriculture, Forestry and Bioresources, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
Samsung SDI, 150-20, Gongse-ro, Giheung-gu, Yongin, Gyeonggi-do, 17084, Republic of Korea.
Nat Commun. 2024 Nov 29;15(1):10394. doi: 10.1038/s41467-024-54588-1.
Many studies try to comprehend and replicate the natural silk spinning process due to its energy-efficient and eco-friendly process. In contrast to spider silk, the mechanisms of how silkworm silk fibroin (SF) undergoes liquid-liquid phase separation (LLPS) concerning the various environmental factors in the silk glands or how the SF coacervates transform into fibers remain unexplored. Here, we show that calcium ions, among the most abundant metal ions inside the silk glands, induce LLPS of SF under macromolecular crowded conditions by increasing both hydrophobic and electrostatic interactions between SF. Furthermore, SF coacervates assemble and further develop into fibrils under acidification and shear force. Finally, we prepare SF fiber using a pultrusion-based dry spinning, mirroring the natural silk spinning system. Unlike previous artificial spinning methods requiring concentrated solutions or harsh solvents, our process uses a less concentrated aqueous SF solution and minimal shear force, offering a biomimetic approach to fiber production.
许多研究试图理解和复制天然丝纺过程，因为它具有节能和环保的特点。与蜘蛛丝不同，家蚕丝素蛋白（SF）在丝腺中受到各种环境因素影响时如何发生液-液相分离（LLPS），以及 SF 凝聚物如何转化为纤维的机制仍未被探索。在这里，我们表明，在大分子拥挤的条件下，丝腺中最丰富的金属离子之一钙离子通过增加 SF 之间的疏水相互作用和静电相互作用来诱导 SF 的 LLPS。此外，SF 凝聚物在酸化和剪切力的作用下组装并进一步发展成纤维。最后，我们使用基于挤压的干法纺丝制备 SF 纤维，模拟天然丝纺系统。与以前需要浓缩溶液或苛刻溶剂的人工纺丝方法不同，我们的方法使用浓度较低的 SF 水溶液和最小的剪切力，为纤维生产提供了一种仿生方法。
