Mu Xuan, Amouzandeh Reza, Vogts Hannah, Luallen Elise, Arzani Milad
Roy J. Carver Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, IA, United States.
Front Bioeng Biotechnol. 2023 Sep 6;11:1252499. doi: 10.3389/fbioe.2023.1252499. eCollection 2023.
Silk spinning, observed in spiders and insects, exhibits a remarkable biological source of inspiration for advanced polymer fabrications. Because of the systems design, silk spinning represents a holistic and circular approach to sustainable polymer fabrication, characterized by renewable resources, ambient and aqueous processing conditions, and fully recyclable "wastes." Also, silk spinning results in structures that are characterized by the combination of monolithic proteinaceous composition and mechanical strength, as well as demonstrate tunable degradation profiles and minimal immunogenicity, thus making it a viable alternative to most synthetic polymers for the development of advanced biomedical devices. However, the fundamental mechanisms of silk spinning remain incompletely understood, thus impeding the efforts to harness the advantageous properties of silk spinning. Here, we present a concise and timely review of several essential features of silk spinning, including the molecular designs of silk proteins and the solvent cues along the spinning apparatus. The solvent cues, including salt ions, pH, and water content, are suggested to direct the hierarchical assembly of silk proteins and thus play a central role in silk spinning. We also discuss several hypotheses on the roles of solvent cues to provide a relatively comprehensive analysis and to identify the current knowledge gap. We then review the state-of-the-art bioinspired fabrications with silk proteins, including fiber spinning and additive approaches/three-dimensional (3D) printing. An emphasis throughout the article is placed on the universal characteristics of silk spinning developed through millions of years of individual evolution pathways in spiders and silkworms. This review serves as a stepping stone for future research endeavors, facilitating the recapitulation of silk spinning and advancing the field of bioinspired polymer fabrication.
在蜘蛛和昆虫身上观察到的吐丝现象，为先进的聚合物制造提供了一种引人注目的生物灵感来源。由于其系统设计，吐丝代表了一种可持续聚合物制造的整体循环方法，其特点是使用可再生资源、在环境和水性加工条件下进行加工，以及产生完全可回收的“废料”。此外，吐丝形成的结构具有整体蛋白质成分与机械强度相结合的特点，还展示出可调节的降解特性和最小的免疫原性，因此使其成为开发先进生物医学设备时大多数合成聚合物的可行替代品。然而，吐丝的基本机制仍未完全被理解，这阻碍了人们利用吐丝有利特性的努力。在此，我们对吐丝的几个基本特征进行了简要且及时的综述，包括丝蛋白的分子设计以及沿吐丝装置的溶剂线索。溶剂线索，包括盐离子、pH值和含水量，被认为能指导丝蛋白的分级组装，从而在吐丝过程中发挥核心作用。我们还讨论了关于溶剂线索作用的几种假说，以提供相对全面的分析并确定当前的知识空白。然后，我们回顾了利用丝蛋白进行的前沿仿生制造，包括纤维纺丝和添加剂方法/三维（3D）打印。本文通篇强调了蜘蛛和蚕在数百万年各自进化路径中发展出的吐丝的普遍特征。这篇综述为未来的研究工作奠定了基础，有助于重现吐丝过程并推动仿生聚合物制造领域的发展。
