Revealing Spider Silk's 3D Nanostructure Through Low Temperature Plasma Etching and Advanced Low-Voltage SEM
Revealing Spider Silk's 3D Nanostructure Through Low Temperature Plasma Etching and Advanced Low-Voltage SEM
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DOI：
10.3389/fmats.2018.00084
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发表时间：
2019-01-25
影响因子：
3.2
通讯作者：
Rodenburg, Cornelia
中科院分区：
文献类型：
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作者：
Stehling, Nicola;Abrams, Kerry J.;Rodenburg, Cornelia
蜘蛛拖丝优异的力学性能与其在纺丝过程中形成的多尺度分层结构密切相关。如果要理解和模仿这一点，必须出现多尺度模型，有效地跨越长度尺度。本研究旨在通过使用低温等离子体蚀刻和先进的低压扫描电子显微镜（LV-SEM）来揭示Nephila拖丝的结构，从而实现这一目标。结果表明，二次电子高光谱成像（SEHI）对微纳米尺度上的成分差异都很敏感。在较大的尺度上，它可以区分脂质最外层和蛋白质核心，而在较小的尺度上，SEHI可以更好地分辨基质中存在的纳米结构。关键的结果表明，以较低的缫丝速度纺成的丝在纤维中往往有更大比例的更小的纳米结构，这些纳米结构彼此靠近，我们将其与纤维的高韧性和低刚度联系起来。有序畴的双峰尺寸分布、它们的径向分布、纳米尺度的间距，以及至关重要的它们之间的相互作用，可能是弥合目前蜘蛛丝结构-性质模型中存在的长度尺度差距的关键。最终，这将使新模型的仿生学实现成功。
The excellent mechanical properties of spider dragline silk are closely linked to its multiscale hierarchical structuring which develops as it is spun. If this is to be understood andmimicked, multiscale models must emerge which effectively bridge the length scales. This study aims to contribute to this goal by exposing structures within Nephila dragline silk using low-temperature plasma etching and advanced Low Voltage Scanning Electron Microscopy (LV-SEM). It is shown that Secondary Electron Hyperspectral Imaging (SEHI) is sensitive to compositional differences on both the micro and nano scale. On larger scales it can distinguish the lipids outermost layer from the protein core, while at smaller scales SEHI is effective in better resolving nanostructures present in the matrix. Key results suggest that the silks spun at lower reeling speeds tend to have a greater proportion of smaller nanostructures in closer proximity to one-another in the fiber, which we associate with the fiber's higher toughness but lower stiffness. The bimodal size distribution of ordered domains, their radial distribution, nanoscale spacings, and crucially their interactions may be key in bridging the length scale gaps which remain in current spider silk structure-property models. Ultimately this will allow successful biomimetic implementation of new models.