【作者】 刘敏；

【导师】 潘志娟；

【作者基本信息】 苏州大学 ， 纺织材料及纺品设计， 2004， 硕士

【摘要】 蜘蛛牵引丝因其具有的高强度、高弹性、高断裂功等优异的力学性能，自70年代以来就受到研究人员的关注，至20世纪90年代以后掀起了蜘蛛丝的研究高潮。目前，采用基因工程技术制备人工蛛丝蛋白的研究已取得了初步的成果，也制备得到了具有良好力学性能的基因重组蜘蛛丝纤维，但其力学性能和天然蜘蛛牵引丝相比还有一定的差距。蛛丝纤维的力学性能一方面与其氨基酸组成及其序列有关，同时还取决于大分子链的结构和聚集态结构。分析和探索蜘蛛成丝过程中的微观结构变化规律，研究蜘蛛丝的成丝条件，成丝方式与其结构和性能的关系，将能更进一步探明蜘蛛丝力学性能的形成过程。同时，蜘蛛丝成丝机理的研究，也将为确定人造蜘蛛丝的纺丝技术和工艺，提供一定的理论依据。 本文以广泛分布于我国各地的大腹园蛛为对象，研究了大腹园蛛主腺体内丝蛋白溶液的分子量和氨基酸组成，并利用圆二色光谱和拉曼光谱分析了蜘蛛在不同成丝阶段丝蛋白的分子构象和聚集态结构的变化，以期了解蜘蛛主腺体内丝蛋白的分子组成及其生物纺丝机制。用拉曼光谱及原子力显微镜研究了不同成丝速度和成丝方式下蜘蛛主腺体丝的分子构象和微细结构，并分析了其力学性能，以揭示成丝条件和方式对蜘蛛丝结构和性能的影响。采用麻醉的方法研究蜘蛛在逐步失去自我控制的过程中分泌的牵引丝的力学行为，以探索蜘蛛对成丝的控制能力与纤维性能间的关系，分析了成丝张力和湿度对牵引丝力学性能的影响。研究结果表明：蜘蛛主腺体丝蛋白由一个200kDa和另一个约300kDa的亚基组成；丝蛋白的氨基酸组成以甘氨酸、丙氨酸和谷氨酸为主；丝蛋白液在蜘蛛主腺体内流动时会因剪切应力、流动伸长、管径变化等因素的影响而发生结构的变化，部分α-螺旋和无规卷曲构象的分子逐渐转变为β-折叠构象，出吐丝口后，牵引丝由于在空气中受到的拉伸使β-折叠结构的分子数进一步增加，分子链取向增加；成丝速度和方式均会影响蜘蛛牵引丝的结构和性能，随卷取速度的增加，牵引丝的断裂强度在10-20mm／s范围内有一最大值，并且在纤维强度的最佳点，其β-折叠特征峰的强度最大，分子链的取向最佳，断裂伸长率和断裂比功整体呈下降趋势，同时牵引丝表面的粗糙度因成丝速度而不同；蜘蛛垂直下落时分泌的牵引丝的断裂强力、断裂伸长率及断裂比功均比相似速度下人工卷取的牵引丝大得蜘蛛丝成丝机理的研究摘要多，且丝纤维内p一折叠构象特征峰的强度以及p一折叠分子链的取向都比相似速度下人工卷取的牵引丝高得多，AFM的研究表明两者的微细结构存在区别;另外，成丝时的外界条件如麻醉、成丝张力和湿度等均会影响蜘蛛牵引丝的力学性能。更多还原

【Abstract】 Spider silk has attracted a great number of researchers’ attention because of it’s high strength , high elasticity and high break energy from 70’s, and until 20th 90’s the research climax came. At present, artificial spidroin produced by genetic engineering has got first fruits and recombinant spider silk with good mechanical properties has been made, but there is still some difference in mechanical properties between the artificial spider silk and the nature one. The mechanical properties not only correlate with it’s amino acid compositions and sequences, but also depend on the molecular structures and morphologies. It is necessary to explore the change of microstructures in the spinning process of spider silk, and study the relationship between spinning condition, spinning method and properties to know how a spider spins it’s silk, which also provide some theory bases for producing artificial spider silk.Araneus Ventrcosus spiders are collected as our study object that widely distribute in China. To realize the molecular compositions and bio-spinning mechanisms of spidroin in spider major ampullate, the molecular weight and amino acid compositions of spidrion solution were measured and compared with that of dragline silk. The molecular conformations and morphologies of spidroin and dragline silk in different spinning phases were determined by circular dichroism (CD) spectroscopy and laser Raman spectroscopy. To understand how the spinning speed and method influence structures and properties of spider dragline silk, the molecular conformations and microstructures of dragline silk fibers obtained at several rolling speeds and secreted by a falling spider were investigated by laser Raman spectrum and atomic force microscopy (AFM). The mechanical properties of these silk fibers were also measured. To explore the control capability of spider on the spinning process and it’s influence on the mechanical properties of dragline silk, spiders were anaesthetized and the mechanical properties of dragline silk reeled from an being anaesthetized spider were measured. We also studied the relationship between spinning tension, humidity and the mechanical properties of dragline silk. The results showed thatspidroin in spider major ampullate had two molecular weights, 200KDa and 300KDa and were mainly composed of Alanine, Glycine and Glutamine. The structure of spider spidroin changed during flowing through the major ampullate because of the shear stress, flow elongation, change of duct diameter etc., some of the a -helix and random coil molecules turned into B -sheet ones. After the dragline silk leaving the spinneret, the fibers had more highly oriented molecules with B-sheet conformations. Spinning speed and method both affected the structures and properties of spider dragline silk. The break strength of dragline silk had a maximum in the rolling speed range of 10mm/s to 20mm/s. At that point, there was also the highest intensity corresponding with B-sheet conformation and the molecular orientation was the best The break strain and surface toughness of dragline silk had decrease trends. AFM images showed the surface roughness of dragline silk varied with the spinning speed. The break strength, break strain and toughness of dragline silk obtained from a falling spider were bigger than that of silk reeled at the similar speed. The former had much more B-sheet molecules with higher orientation and AFM results showed that their microstructures were different. The environment condition during spinning such as anaesthetization, humidity and spinning tension could change the mechanical properties of dragline silk.更多还原