Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, U.K.
Sustainable Aviation Fuels Innovation Centre, University of Sheffield, Sheffield Business Park, Europa Avenue, Sheffield S9 1ZA, U.K.
Biomacromolecules. 2023 Jun 12;24(6):2828-2846. doi: 10.1021/acs.biomac.3c00233. Epub 2023 May 26.
The ability of many arthropods to spin silk and its many uses bear testament to its importance in Nature. Despite over a century of research, however, the spinning process is still not fully understood. While it is widely accepted that flow and chain alignment may be involved, the link to protein gelation remains obscure. Using combinations of rheology, polarized light imaging, and infrared spectroscopy to probe different length scales, this work explored flow-induced gelation of native silk feedstock from larvae. Protein chain deformation, orientation, and microphase separation were observed, culminating in the formation of antiparallel β-sheet structures while the work rate during flow appeared as an important criterion. Moreover, infrared spectroscopy provided direct observations suggesting a loss of protein hydration during flow-induced gelation of fibroin in native silk feedstock, which is consistent with recently reported hypotheses.
许多节肢动物能够吐丝，而且丝有多种用途，这证明了它在自然界中的重要性。然而，尽管已经进行了一个多世纪的研究，但对这一过程仍然没有完全了解。虽然人们普遍认为流动和链排列可能与之相关，但与蛋白质胶凝的联系仍然不清楚。本工作使用流变学、偏光成像和红外光谱相结合的方法，从幼虫中探测不同的长度尺度，研究了天然丝原料的流致凝胶化过程。观察到了蛋白质链的变形、取向和微相分离，最终形成了反平行β-折叠结构，而在流动过程中的工作速率似乎是一个重要的标准。此外，红外光谱提供了直接的观察结果，表明在天然丝原料中丝素蛋白的流致凝胶化过程中，蛋白质的水合作用丧失，这与最近报道的假说一致。
