scholarly journals Hydrothermal Effect on Mechanical Properties of Nephila pilipes Spidroin

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1013 ◽  
Author(s):  
Hsuan-Chen Wu ◽  
Aditi Pandey ◽  
Liang-Yu Chang ◽  
Chieh-Yun Hsu ◽  
Thomas Chung-Kuang Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Spider Silk ◽  
Post Treatment ◽  
Molecular Structures ◽  
Random Coil ◽  
Silk Fibers ◽  
Physical Strength ◽  
Β Sheet ◽  
Post Treatment Process

The superlative mechanical properties of spider silk and its conspicuous variations have instigated significant interest over the past few years. However, current attempts to synthetically spin spider silk fibers often yield an inferior physical performance, owing to the improper molecular interactions of silk proteins. Considering this, herein, a post-treatment process to reorganize molecular structures and improve the physical strength of spider silk is reported. The major ampullate dragline silk from Nephila pilipes with a high β-sheet content and an adequate tensile strength was utilized as the study material, while that from Cyrtophora moluccensis was regarded as a reference. Our results indicated that the hydrothermal post-treatment (50–70 °C) of natural spider silk could effectively induce the alternation of secondary structures (random coil to β-sheet) and increase the overall tensile strength of the silk. Such advantageous post-treatment strategy when applied to regenerated spider silk also leads to an increment in the strength by ~2.5–3.0 folds, recapitulating ~90% of the strength of native spider silk. Overall, this study provides a facile and effective post-spinning means for enhancing the molecular structures and mechanical properties of as-spun silk threads, both natural and regenerated.

scholarly journals Strain softening and stiffening responses of spider silk fibers probed using a Micro-Extension Rheometer

Soft Matter ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 487-493
Author(s):  
Sushil Dubey ◽  
Chinmay Hemant Joshi ◽  
Sukh Veer ◽  
Divya Uma ◽  
Hema Somanathan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Spider Silk ◽  
Strain Softening ◽  
High Tensile Strength ◽  
Silk Fibers

Spider silk possesses unique mechanical properties like large extensibility, high tensile strength, super-contractility, etc.

scholarly journals Presence of β-Turn Structure in Recombinant Spider Silk Dissolved in Formic Acid Revealed with NMR

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 511
Author(s):  
Yu Suzuki ◽  
Takanori Higashi ◽  
Takahiro Yamamoto ◽  
Hideyasu Okamura ◽  
Takehiro K. Sato ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Formic Acid ◽  
Spider Silk ◽  
Chemical Shifts ◽  
Repetitive Sequences ◽  
Silk Protein ◽  
Random Coil ◽  
Oh Groups ◽  
Spider Silk Protein ◽  
Turn Structure

Spider dragline silk is a biopolymer with excellent mechanical properties. The development of recombinant spider silk protein (RSP)-based materials with these properties is desirable. Formic acid (FA) is a spinning solvent for regenerated Bombyx mori silk fiber with excellent mechanical properties. To use FA as a spinning solvent for RSP with the sequence of major ampullate spider silk protein from Araneus diadematus, we determined the conformation of RSP in FA using solution NMR to determine the role of FA as a spinning solvent. We assigned 1H, 13C, and 15N chemical shifts to 32-residue repetitive sequences, including polyAla and Gly-rich regions of RSP. Chemical shift evaluation revealed that RSP is in mainly random coil conformation with partially type II β-turn structure in the Gly-Pro-Gly-X motifs of the Gly-rich region in FA, which was confirmed by the 15N NOE data. In addition, formylation at the Ser OH groups occurred in FA. Furthermore, we evaluated the conformation of the as-cast film of RSP dissolved in FA using solid-state NMR and found that β-sheet structure was predominantly formed.

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

Molecules ◽  
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.

Effect of chain extender on the mechanical and thermal resistance properties of polyurethane liners for composite propellants

Polyurethanes ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
P. Ross ◽  
G. Sevilla ◽  
J. Quagliano
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Chain Extender ◽  
Molecular Structures ◽  
Polymer Chains ◽  
Mechanical And Thermal Properties ◽  
Thermal Changes ◽  
Ft Ir ◽  
Chain Lengths

AbstractPolyurethane formulations utilized as liners for composite propellants were prepared by the reaction of toluene-2,4-diisocyanate (TDI) and isophorone diisocyanate (IPDI) with hydroxyl terminated polybutadiene (HTPB), while polymer chains were further extended with neopentyl glycol diol, NPG triol and two different triols (monoglyceryl ricinoleate, MRG and trimethylolpropane, TMP). Liners were formulated with micronized titanium dioxide mechanically dispersed in hydroxyl-terminated polybutadiene (HTPB). The molecular structures of liners were confirmed by FT-IR. Thermal properties indicated that the nature of chain extender (crosslinker) only slightly affected the temperatures for decomposition of liners. Two main thermal changes were found at 370∘C and another at around 440–500∘C, depending on the chain extender utilized. On the other side, mechanical properties varied within the range of 0,7-1,8 MPa, consistent with this kind of elastomers. Tensile strength at break was only significantly affected with TMP and MRG-chain extended liners at the lowest concentrations tested of 1,3 and 2% (w/w), respectively. However, the behaviour depended on whether TDI or IPDI isocyanate was utilized for curing. TMP 1,3% crosslinked liner cured with TDI had a tensile strength of 1,82MPa whileMRG-crosslinked liner cured with IPDI had a tensile strength of 1,56 MPa. It was observed that at the higher NCO/OH ratios essayed, tensile strength and hardness increased, improving mechanical properties. Our results confirmed that TMP and MRG triols together with NPG diols can be used to tailor mechanical and thermal properties of liners, considering their different hydroxyl functionalities and chain lengths.

scholarly journals Mechanical properties and application analysis of spider silk bionic material

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 443-457
Author(s):  
Yunqing Gu ◽  
Lingzhi Yu ◽  
Jiegang Mou ◽  
Denghao Wu ◽  
Peijian Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Spider Silk ◽  
Superior Performance ◽  
Biomimetic Materials ◽  
Silk Fibers ◽  
Practical Applications ◽  
Spider Web ◽  
Potential Applications ◽  
And Performance ◽  
Fiber Materials

AbstractSpider silk is a kind of natural biomaterial with superior performance. Its mechanical properties and biocompatibility are incomparable with those of other natural and artificial materials. This article first summarizes the structure and the characteristics of natural spider silk. It shows the great research value of spider silk and spider silk bionic materials. Then, the development status of spider silk bionic materials is reviewed from the perspectives of material mechanical properties and application. The part of the material characteristics mainly describes the biocomposites based on spider silk proteins and spider silk fibers, nanomaterials and man-made fiber materials based on spider silk and spider-web structures. The principles and characteristics of new materials and their potential applications in the future are described. In addition, from the perspective of practical applications, the latest application of spider silk biomimetic materials in the fields of medicine, textiles, and sensors is reviewed, and the inspiration, feasibility, and performance of finished products are briefly introduced and analyzed. Finally, the research directions and future development trends of spider silk biomimetic materials are prospected.

scholarly journals Effect of Different Additives in Diets on Secondary Structure, Thermal and Mechanical Properties of Silkworm Silk

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 14 ◽  
Author(s):  
Lan Cheng ◽  
Huiming Huang ◽  
Jingyou Zeng ◽  
Zulan Liu ◽  
Xiaoling Tong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Amino Acid ◽  
Large Scale ◽  
Fiber Composites ◽  
Metallic Ions ◽  
Silk Fibers ◽  
Random Coils ◽  
Silkworm Silk ◽  
Β Sheet

In this study, eight types of materials including nanoparticles (Cu and CaCO3), metallic ions (Ca2+ and Cu2+), and amino acid substances (serine, tyrosine, sericin amino acid, and fibroin amino acid) were used as additives in silkworm diets to obtain in-situ modified silk fiber composites. The results indicate that tyrosine and fibroin amino acids significantly increase potassium content in silk fibers and induce the transformation of α-helices and random coils to β-sheet structures, resulting in higher crystallinities and better mechanical properties. However, the other additives-modified silk fibers show a decrease in β-sheet contents and a slight increase or even decrease in tensile strengths. This finding provides a green and effective approach to produce mechanically enhanced silk fibers with high crystallinity on a large scale. Moreover, the modification mechanisms of these additives were discussed in this study, which could offer new insights into the design and regulation of modified fibers or composites with desirable properties and functions.

scholarly journals Relationship between microstructure and mechanical properties in spider silk fibers: identification of two regimes in the microstructural changes

Soft Matter ◽  
2012 ◽  
Vol 8 (22) ◽  
pp. 6015 ◽  
Author(s):  
Gustavo R. Plaza ◽  
José Pérez-Rigueiro ◽  
Christian Riekel ◽  
G. Belén Perea ◽  
Fernando Agulló-Rueda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Spider Silk ◽  
Microstructural Changes ◽  
Silk Fibers ◽  
Microstructure And Mechanical Properties

scholarly journals Post-secretion processing influences spider silk performance

2012 ◽  
Vol 9 (75) ◽  
pp. 2479-2487 ◽  
Author(s):  
Sean J. Blamires ◽  
Chung-Lin Wu ◽  
Todd A. Blackledge ◽  
I-Min Tso
Keyword(s):  
Mechanical Properties ◽  
Amino Acid ◽  
Ground State ◽  
Spider Silk ◽  
Mechanical Performance ◽  
Protein Composition ◽  
Compositional Changes ◽  
Spinning Speed ◽  
Spider Silks ◽  
Β Sheet

Phenotypic variation facilitates adaptations to novel environments. Silk is an example of a highly variable biomaterial. The two-spidroin (MaSp) model suggests that spider major ampullate (MA) silk is composed of two proteins—MaSp1 predominately contains alanine and glycine and forms strength enhancing β-sheet crystals, while MaSp2 contains proline and forms elastic spirals. Nonetheless, mechanical properties can vary in spider silks without congruent amino acid compositional changes. We predicted that post-secretion processing causes variation in the mechanical performance of wild MA silk independent of protein composition or spinning speed across 10 species of spider. We used supercontraction to remove post-secretion effects and compared the mechanics of silk in this ‘ground state’ with wild native silks. Native silk mechanics varied less among species compared with ‘ground state’ silks. Variability in the mechanics of ‘ground state’ silks was associated with proline composition. However, variability in native silks did not. We attribute interspecific similarities in the mechanical properties of native silks, regardless of amino acid compositions, to glandular processes altering molecular alignment of the proteins prior to extrusion. Such post-secretion processing may enable MA silk to maintain functionality across environments, facilitating its function as a component of an insect-catching web.

scholarly journals Basic Principles in the Design of Spider Silk Fibers

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1794
Author(s):  
José Pérez-Rigueiro ◽  
Manuel Elices ◽  
Gustavo R. Plaza ◽  
Gustavo V. Guinea
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Spider Silk ◽  
Design Principles ◽  
Tensile Behavior ◽  
Original Design ◽  
Basic Principles ◽  
Silk Fibers ◽  
The Relationship ◽  
Selection Of

The prominence of spider silk as a hallmark in biomimetics relies not only on its unrivalled mechanical properties, but also on how these properties are the result of a set of original design principles. In this sense, the study of spider silk summarizes most of the main topics relevant to the field and, consequently, offers a nice example on how these topics could be considered in other biomimetic systems. This review is intended to present a selection of some of the essential design principles that underlie the singular microstructure of major ampullate gland silk, as well as to show how the interplay between them leads to the outstanding tensile behavior of spider silk. Following this rationale, the mechanical behavior of the material is analyzed in detail and connected with its main microstructural features, specifically with those derived from the semicrystalline organization of the fibers. Establishing the relationship between mechanical properties and microstructure in spider silk not only offers a vivid image of the paths explored by nature in the search for high performance materials, but is also a valuable guide for the development of new artificial fibers inspired in their natural counterparts.

scholarly journals Expanding Canonical Spider Silk Properties through a DNA Combinatorial Approach

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3596
Author(s):  
Zaroug Jaleel ◽  
Shun Zhou ◽  
Zaira Martín-Moldes ◽  
Lauren M. Baugh ◽  
Jonathan Yeh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Recombinant Proteins ◽  
Elastic Moduli ◽  
Spider Silk ◽  
Building Blocks ◽  
Random Coil ◽  
Infrared Spectrometry ◽  
Silk Proteins ◽  
Dragline Silk ◽  
Latrodectus Hesperus

The properties of native spider silk vary within and across species due to the presence of different genes containing conserved repetitive core domains encoding a variety of silk proteins. Previous studies seeking to understand the function and material properties of these domains focused primarily on the analysis of dragline silk proteins, MaSp1 and MaSp2. Our work seeks to broaden the mechanical properties of silk-based biomaterials by establishing two libraries containing genes from the repetitive core region of the native Latrodectus hesperus silk genome (Library A: genes masp1, masp2, tusp1, acsp1; Library B: genes acsp1, pysp1, misp1, flag). The expressed and purified proteins were analyzed through Fourier Transform Infrared Spectrometry (FTIR). Some of these new proteins revealed a higher portion of β-sheet content in recombinant proteins produced from gene constructs containing a combination of masp1/masp2 and acsp1/tusp1 genes than recombinant proteins which consisted solely of dragline silk genes (Library A). A higher portion of β-turn and random coil content was identified in recombinant proteins from pysp1 and flag genes (Library B). Mechanical characterization of selected proteins purified from Library A and Library B formed into films was assessed by Atomic Force Microscopy (AFM) and suggested Library A recombinant proteins had higher elastic moduli when compared to Library B recombinant proteins. Both libraries had higher elastic moduli when compared to native spider silk proteins. The preliminary approach demonstrated here suggests that repetitive core regions of the aforementioned genes can be used as building blocks for new silk-based biomaterials with varying mechanical properties.

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