Nanoconfinement of Spider Silk Fibrils Begets Superior Strength, Extensibility, and Toughness

被引:226
作者
Giesa, Tristan [1 ,2 ]
Arslan, Melis [1 ]
Pugno, Nicola M. [3 ]
Buehler, Markus J. [1 ]
机构
[1] MIT, Dept Civil & Environm Engn, Lab Atomist & Mol Mech, Cambridge, MA 02138 USA
[2] Rhein Westfal TH Aachen, Dept Mech Engn, D-52056 Aachen, Germany
[3] Politecn Torino, Dept Struct Engn, Lab Bio Inspired Nanomech Giuseppe Maria Pugno, I-10129 Turin, Italy
基金
美国国家科学基金会;
关键词
Spider silk; mechanical properties; deformation; geometric confinement; molecular simulation; coarse-grain model; materiomics; SKIN-CORE STRUCTURE; ELECTRON-MICROSCOPY; DRAGLINE SILK; STRUCTURAL ORGANIZATION; MECHANICAL-PROPERTIES; BIOLOGICAL-MATERIALS; MOLECULAR-DYNAMICS; NANOSTRUCTURE; DEFORMATION; PROTEIN;
D O I
10.1021/nl203108t
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Silk is an exceptionally strong, extensible, and tough material made from simple protein building blocks. The molecular structure of dragline spider silk repeat units consists of semiamorphous and nanocrystalline beta-sheet protein domains. Here we show by a series of computational experiments how the nanoscale properties of silk repeat units are scaled up to create macroscopic silk fibers with outstanding mechanical properties despite the presence of cavities, tears, and cracks. We demonstrate that the geometric confinement of silk fibrils to diameters of 50 +/- 30 nm is critical to facilitate a powerful mechanism by which hundreds of thousands of protein domains synergistically resist deformation and failure to provide enhanced strength, extensibility, and toughness at the macroscale, closely matching experimentally measured mechanical properties. Through this mechanism silk fibers exploit the full potential of the nanoscale building blocks, regardless of the details of microscopic loading conditions and despite the presence of large defects. Experimental results confirm that silk fibers are composed of silk fibril bundles with diameters in the range of 20-150 nm, in agreement with our predicted length scale. Our study reveals a general mechanism to map nanoscale properties to the macroscale and provides a potent design strategy toward novel fiber and bulk nanomaterials through hierarchical structures.
引用
收藏
页码:5038 / 5046
页数:9
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