STRUCTURAL STUDIES OF SPIDER-SILK FIBERS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 蜘蛛一直在使用基于蛋白质的纳米材料，这些材料具有自组装成纤维和薄片的能力超过4.5亿年。 然而，只是在过去的15年里，我们才开始了解这些惊人材料的基础。 生物聚合物和组装体，如蜘蛛丝，通常是长的、螺旋状的纤维结构。 这些纤维组装体的组分难以结晶，因为它们的自然趋势是形成纤维。蜘蛛拖丝具有非常卓越的机械强度，结合了非常高的弹性和拉伸强度。了解丝纤维的微观结构对于理解决定这些独特机械性能的因素至关重要。关于其结构的知识将有助于理解结构-性能关系，从而使其能够用作新的智能生物材料，用于从安全气囊到传感器到微缝合线到人工韧带和肌腱到药物输送涂层的众多应用。 纤维衍射是在分子水平上测定这些组件结构的唯一实用方法。纤维和晶体之间的区别在于，在纤维中，分子彼此平行（就像它们在晶体中一样），但它们围绕纤维的长轴随机旋转。结果，从X射线纤维衍射实验获得的数据相对于从相同聚集体的假设晶体获得的数据进行圆柱平均。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Spiders have been using protein-based nanomaterials that have the ability to self-assemble into fibers and sheets for over 450 million years. However, it is only in the past 15 years that we have started to understand the basis for these amazing materials. Biological polymers and assemblies, such as spider silk, are typically long, helical, fibrous structures. The components of these fibrous-assemblies are difficult to crystallize, since their natural tendency is to form fibers. Spider dragline silks have extremely unsurpassed mechanical strength, a combination of very high elasticity and tensile strength. A knowledge of the micro-structure of the silk fibers is crucial in understanding the factors deciding on these unique mechanical properties. This knowledge about its structure would help understanding the structure-property relationship and inturn enable it to be used as new smart bio-materials, for numerous applications ranging from airbags to sensors to micro-sutures to artificial ligaments and tendons to drug delivery coatings. Fiber diffraction is the only practical method of structure determination at the molecular level for these assemblies. The difference between fibers and crystals is that, in fibers, the molecules are parallel to each other (as they are in crystals), but they are randomly rotated about the long axis of the fiber. As a result, the data obtained from an x-ray fiber diffraction experiment are cylindrically averaged relative to the data that would be obtained from a hypothetical crystal of the same aggregate.