Scalable Spider Silk Inspired Materials with High Extensibility and Super Toughness

Spiders silks have extraordinary strength and toughness simultaneously, thus has become dreamed materials by scientists and industries. Although there have been tremendous attempts to prepare fibers from genetically manufacture spider silk proteins, however, it has been still a huge challenge because of tedious procedure and high cost. Here, a facile spider-silk-mimicking strategy is reported for preparing highly scratchable polymers and supertough fibers from chemical synthesis route. Polymer films with high extensibility (>1200%) and supertough fibers (~387 MJ m-3) are achieved by introducing polypeptides with β-sheet and α-helical structure in polyureathane/urea polymers. Notabley,the toughness of the fiber is more than twice the reported value of a normal spider dragline silk, and comparable with the toughest spider silk, aciniform silk of Argiope trifasciata.

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Chemical Synthesis of Multiblock Copolypeptides Inspired by Spider Dragline Silk Proteins

ACS Macro Letters ◽

10.1021/acsmacrolett.7b00006 ◽

2017 ◽

Vol 6 (2) ◽

pp. 103-106 ◽

Cited By ~ 18

Author(s):

Kousuke Tsuchiya ◽

Keiji Numata

Keyword(s):

Chemical Synthesis ◽

Silk Proteins ◽

Dragline Silk ◽

Spider Dragline Silk

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Properties of Biomimetic Artificial Spider Silk Fibers Tuned by PostSpin Bath Incubation

Molecules ◽

10.3390/molecules25143248 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3248

Author(s):

Gabriele Greco ◽

Juanita Francis ◽

Tina Arndt ◽

Benjamin Schmuck ◽

Fredrik G. Bäcklund ◽

...

Keyword(s):

Spider Silk ◽

Molecular Mechanisms ◽

Efficient Production ◽

Fiber Morphology ◽

Silk Proteins ◽

Silk Fibers ◽

Aqueous Environments ◽

Natural Counterpart ◽

Phosphate Buffered Saline ◽

Β Sheet

Efficient production of artificial spider silk fibers with properties that match its natural counterpart has still not been achieved. Recently, a biomimetic process for spinning recombinant spider silk proteins (spidroins) was presented, in which important molecular mechanisms involved in native spider silk spinning were recapitulated. However, drawbacks of these fibers included inferior mechanical properties and problems with low resistance to aqueous environments. In this work, we show that ≥5 h incubation of the fibers, in a collection bath of 500 mM NaAc and 200 mM NaCl, at pH 5 results in fibers that do not dissolve in water or phosphate buffered saline, which implies that the fibers can be used for applications that involve wet/humid conditions. Furthermore, incubation in the collection bath improved the strain at break and was associated with increased β-sheet content, but did not affect the fiber morphology. In summary, we present a simple way to improve artificial spider silk fiber strain at break and resistance to aqueous solvents.

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Artificial spider silk is smart like natural one: having humidity-sensitive shape memory with superior recovery stress

Materials Chemistry Frontiers ◽

10.1039/c9qm00261h ◽

2019 ◽

Vol 3 (11) ◽

pp. 2472-2482 ◽

Cited By ~ 2

Author(s):

Harun Venkatesan ◽

Jianming Chen ◽

Haiyang Liu ◽

Yoonjung Kim ◽

Sungsoo Na ◽

...

Keyword(s):

Shape Memory ◽

Spider Silk ◽

Recovery Stress ◽

Dragline Silk ◽

Spider Dragline Silk ◽

Shape Memory Behaviour

Inspired by supercontraction, the recombinant spider dragline silk displayed humidity-responsive shape memory behaviour with impressive recovery stress.

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Triggered Morphology Generation in a Biosynthetic Model Spider Dragline Silk Protein

Microscopy and Microanalysis ◽

10.1017/s1431927600019395 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 1214-1215

Author(s):

R. Valluzzi ◽

S. Szela ◽

D. Kirschner ◽

D. Kaplan

Keyword(s):

Recombinant Dna ◽

Consensus Sequence ◽

Water Soluble ◽

Nephila Clavipes ◽

Dragline Silk ◽

Spider Dragline Silk ◽

Structure Changes ◽

Methionine Residues ◽

Recombinant Dna Techniques ◽

Β Sheet

Recombinant DNA techniques were used to prepare a protein modeled after the consensus sequence of Nephila clavipesspider dragline silk, incorporating methionine residues to serve as redox “triggers”. In addition a water-soluble 27 residue peptide model of the dragline silk consensus amorphous sequence, representing a single amorphous block in the protein sequence, was prepared and characterized to gain additional insight into the behavior of the amorphous phase. X-ray diffraction, electron diffraction, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the ability of the recombinant protein to form (β-sheet crystals and the effect of the oxidation state of the redox trigger on crystallinity and noncrystalline order in the sample. The formation of intractable β-sheet crystallites is a major cause of insolubility in proteins that can form this type of secondary structure. Changes in crystallinity were observed when triggered/reduced (insoluble) and untriggered/oxidized (soluble) protein samples were compared.

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Tensegrity Modelling and the High Toughness of Spider Dragline Silk

Nanomaterials ◽

10.3390/nano10081510 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1510

Author(s):

Fernando Fraternali ◽

Nicola Stehling ◽

Ada Amendola ◽

Bryan Andres Tiban Anrango ◽

Chris Holland ◽

...

Keyword(s):

Spider Silk ◽

Low Voltage ◽

Microstructural Characterization ◽

Hierarchical Organization ◽

Air Plasma ◽

Poisson Effect ◽

Dragline Silk ◽

Spider Dragline Silk ◽

A Chain ◽

Spider Silks

This work establishes a tensegrity model of spider dragline silk. Tensegrity systems are ubiquitous in nature, being able to capture the mechanics of biological shapes through simple and effective modes of deformation via extension and contraction. Guided by quantitative microstructural characterization via air plasma etching and low voltage scanning electron microscopy, we report that this model is able to capture experimentally observed phenomena such as the Poisson effect, tensile stress-strain response, and fibre toughness. This is achieved by accounting for spider silks’ hierarchical organization into microfibrils with radially variable properties. Each fibril is described as a chain of polypeptide tensegrity units formed by crystalline granules operating under compression, which are connected to each other by amorphous links acting under tension. Our results demonstrate, for the first time, that a radial variability in the ductility of tensegrity chains is responsible for high fibre toughness, a defining and desirable feature of spider silk. Based on this model, a discussion about the use of graded tensegrity structures for the optimal design of next-generation biomimetic fibres is presented.

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Nanostructure and molecular mechanics of spider dragline silk protein assemblies

Journal of The Royal Society Interface ◽

10.1098/rsif.2010.0149 ◽

2010 ◽

Vol 7 (53) ◽

pp. 1709-1721 ◽

Cited By ~ 156

Author(s):

Sinan Keten ◽

Markus J. Buehler

Keyword(s):

Secondary Structure ◽

Spider Silk ◽

Mechanical Performance ◽

Experimental Studies ◽

Silk Protein ◽

Nephila Clavipes ◽

Protein Assemblies ◽

Dragline Silk ◽

Spider Dragline Silk ◽

Secondary Structure Content

Spider silk is a self-assembling biopolymer that outperforms most known materials in terms of its mechanical performance, despite its underlying weak chemical bonding based on H-bonds. While experimental studies have shown that the molecular structure of silk proteins has a direct influence on the stiffness, toughness and failure strength of silk, no molecular-level analysis of the nanostructure and associated mechanical properties of silk assemblies have been reported. Here, we report atomic-level structures of MaSp1 and MaSp2 proteins from the Nephila clavipes spider dragline silk sequence, obtained using replica exchange molecular dynamics, and subject these structures to mechanical loading for a detailed nanomechanical analysis. The structural analysis reveals that poly-alanine regions in silk predominantly form distinct and orderly beta-sheet crystal domains, while disorderly regions are formed by glycine-rich repeats that consist of 3 1 -helix type structures and beta-turns. Our structural predictions are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content. Mechanical shearing simulations on selected structures illustrate that the nanoscale behaviour of silk protein assemblies is controlled by the distinctly different secondary structure content and hydrogen bonding in the crystalline and semi-amorphous regions. Both structural and mechanical characterization results show excellent agreement with available experimental evidence. Our findings set the stage for extensive atomistic investigations of silk, which may contribute towards an improved understanding of the source of the strength and toughness of this biological superfibre.

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Microbial repellence properties of engineered spider silk coatings prevent biofilm formation of opportunistic bacterial strains

MRS Communications ◽

10.1557/s43579-021-00034-y ◽

2021 ◽

Author(s):

Christoph Sommer ◽

Hendrik Bargel ◽

Nadine Raßmann ◽

Thomas Scheibel

Keyword(s):

Public Health ◽

Biofilm Formation ◽

Bacterial Infections ◽

Spider Silk ◽

Consensus Sequence ◽

Silicone Implants ◽

Bacterial Strains ◽

Silk Proteins ◽

Dragline Silk ◽

Araneus Diadematus

Abstract Bacterial infections are well recognised to be one of the most important current public health problems. Inhibiting adhesion of microbes on biomaterials is one approach for preventing inflammation. Coatings made of recombinant spider silk proteins based on the consensus sequence of Araneus diadematus dragline silk fibroin 4 have previously shown microbe-repellent properties. Concerning silicone implants, it has been further shown that spider silk coatings are effective in lowering the risk of capsular fibrosis. Here, microbial repellence tests using four opportunistic infection-related strains revealed additional insights into the microbe-repellent properties of spider silk-coated implants, exemplarily shown for silicone surfaces. Graphic Abstract

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Methionine in a protein hydrophobic core drives tight interactions required for assembly of spider silk

Nature Communications ◽

10.1038/s41467-019-12365-5 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 5

Author(s):

Julia C. Heiby ◽

Benedikt Goretzki ◽

Christopher M. Johnson ◽

Ute A. Hellmich ◽

Hannes Neuweiler

Keyword(s):

Amino Acid ◽

Spider Silk ◽

Tight Binding ◽

Pivotal Role ◽

Speed Limit ◽

Hydrophobic Core ◽

Complex Mechanism ◽

Silk Proteins ◽

Dragline Silk ◽

Amino Acid Methionine

Abstract Web spiders connect silk proteins, so-called spidroins, into fibers of extraordinary toughness. The spidroin N-terminal domain (NTD) plays a pivotal role in this process: it polymerizes spidroins through a complex mechanism of dimerization. Here we analyze sequences of spidroin NTDs and find an unusually high content of the amino acid methionine. We simultaneously mutate all methionines present in the hydrophobic core of a spidroin NTD from a nursery web spider’s dragline silk to leucine. The mutated NTD is strongly stabilized and folds at the theoretical speed limit. The structure of the mutant is preserved, yet its ability to dimerize is substantially impaired. We find that side chains of core methionines serve to mobilize the fold, which can thereby access various conformations and adapt the association interface for tight binding. Methionine in a hydrophobic core equips a protein with the capacity to dynamically change shape and thus to optimize its function.

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