School of Molecular Sciences, Magnetic Resonance Research Center , Arizona State University , Tempe , Arizona 85287-1604 , United States.
Australian Future Fibers Research and Innovation Centre, Institute for Frontier Materials , Deakin University , Burwood VIC 3216 , Australia.
Biomacromolecules. 2018 Mar 12;19(3):906-917. doi: 10.1021/acs.biomac.7b01687. Epub 2018 Feb 19.
Silkworm silk has attracted considerable attention in recent years due to its excellent mechanical properties, biocompatibility, and promising applications in biomedical sector. However, a clear understanding of the molecular structure and the relationship between the excellent mechanical properties and the silk protein sequences are still lacking. This study carries out a thorough comparative structural analysis of silk fibers of four silkworm species ( Bombyx mori, Antheraea pernyi, Samia cynthia ricini, and Antheraea assamensis). A combination of characterization techniques including scanning electron microscopy, mechanical test, synchrotron X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and NMR spectroscopy was applied to investigate the morphologies, mechanical properties, amino acid compositions, nanoscale organizations, and molecular structures of various silkworm silks. Furthermore, the structure-property relationship is discussed by correlating the molecular structural features of silks with their mechanical properties. The results show that a high content of β-sheet structures and a high crystallinity would result in a high Young's modulus for silkworm silk fibers. Additionally, a low content of β-sheet structures would result in a high extensibility.
近年来，由于其优异的机械性能、生物相容性以及在生物医学领域的广阔应用前景，家蚕丝备受关注。然而，人们对其优异的机械性能与丝蛋白序列之间的关系及其分子结构仍缺乏清晰的认识。本研究对 4 种家蚕（桑蚕、柞蚕、蓖麻蚕和天蚕）的丝纤维进行了全面的比较结构分析。采用多种表征技术，包括扫描电子显微镜、力学测试、同步辐射 X 射线衍射、傅里叶变换红外光谱（FTIR）和核磁共振波谱（NMR），研究了各种家蚕丝的形貌、力学性能、氨基酸组成、纳米级组织和分子结构。此外，通过将丝的分子结构特征与其力学性能相关联，探讨了结构-性能关系。结果表明，β-折叠结构含量高、结晶度高会导致家蚕丝纤维的杨氏模量高；β-折叠结构含量低会导致丝的伸长率高。
