Guo Kaiyu, Zhang Xiaolu, Dong Zhaoming, Ni Yuhui, Chen Yuqing, Zhang Yan, Li Haoyun, Xia Qingyou, Zhao Ping
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
Biological Science Research Center Southwest University, Chongqing 400716, China.
Polymers (Basel). 2020 Oct 30;12(11):2537. doi: 10.3390/polym12112537.
Ultrafine fibers are widely employed because of their lightness, softness, and warmth retention. Although silkworm silk is one of the most applied natural silks, it is coarse and difficult to transform into ultrafine fibers. Thus, to obtain ultrafine high-performance silk fibers, we employed anti-juvenile hormones in this study to induce bimolter silkworms. We found that the bimolter cocoons were composed of densely packed thin fibers and small apertures, wherein the silk diameter was 54.9% less than that of trimolter silk. Further analysis revealed that the bimolter silk was cleaner and lighter than the control silk. In addition, it was stronger (739 MPa versus 497 MPa) and more stiffness (i.e., a higher Young's modulus) than the trimolter silk. FTIR and X-ray diffraction results revealed that the excellent mechanical properties of bimolter silk can be attributed to the higher β-sheet content and crystallinity. Chitin staining of the anterior silk gland suggested that the lumen is narrower in bimolters, which may lead to the formation of greater numbers of β-sheet structures in the silk. Therefore, this study reveals the relationship between the structures and mechanical properties of bimolter silk and provides a valuable reference for producing high-strength and ultrafine silk fibers.
超细纤维因其轻盈、柔软和保暖性而被广泛应用。尽管蚕丝是应用最广泛的天然丝之一，但它比较粗，难以加工成超细纤维。因此，为了获得超细高性能蚕丝纤维，我们在本研究中使用抗保幼激素来诱导二眠蚕。我们发现二眠蚕茧由紧密排列的细纤维和小孔组成，其中丝直径比三眠蚕丝小54.9%。进一步分析表明，二眠蚕丝比对照丝更洁净、更轻盈。此外，它比三眠蚕丝更强（739兆帕对497兆帕）且更具刚性（即更高的杨氏模量）。傅里叶变换红外光谱（FTIR）和X射线衍射结果表明，二眠蚕丝优异的力学性能可归因于其较高的β-折叠含量和结晶度。前丝腺的几丁质染色表明，二眠蚕的管腔更窄，这可能导致丝中形成更多的β-折叠结构。因此，本研究揭示了二眠蚕丝的结构与力学性能之间的关系，并为生产高强度超细蚕丝纤维提供了有价值的参考。
