Basic Principles in the Design of Spider Silk Fibers

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.

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Spinning conditions affect structure and properties of Nephila spider silk

MRS Bulletin ◽

10.1557/s43577-021-00194-1 ◽

2021 ◽

Author(s):

Robert J. Young ◽

Chris Holland ◽

Zhengzhong Shao ◽

Fritz Vollrath

Keyword(s):

Mechanical Properties ◽

High Performance ◽

Spider Silk ◽

Polymer Fibers ◽

Uniform Strain ◽

Natural Material ◽

Uniform Stress ◽

Silk Fibers ◽

Microstructure And Mechanical Properties ◽

Stress Models

Abstract Raman spectroscopy is used to elucidate the effect of spinning conditions upon the structure and mechanical properties of silk spun by Nephila spiders from the major ampullate gland. Silk fibers produced under natural spinning conditions with spinning rates between 2 and 20 mm s−1 differed in microstructure and mechanical properties from fibers produced either more slowly or more rapidly. The data support the “uniform strain” hypothesis that the reinforcing units in spider silk fibers are subjected to the same strain as the fiber, to optimize the toughness. In contrast, in the case of synthetic high-performance polymer fibers, the both units and the fiber experience uniform stress, which maximizes stiffness. The comparison of Nephila major and minor ampullate silks opens an intriguing window into dragline silk evolution and the first evidence of significant differences between the two silks providing possibilities for further testing of hypotheses concerning the uniform strain versus uniform stress models. Impact statement It is well established that the microstructure and mechanical properties of engineering materials are controlled by the conditions employed to both synthesize and process them. Herein, we demonstrate that the situation is similar for a natural material, namely spider silk. We show that for a spider that normally produces silk at a reeling speed of between 2 and 20 mm s−1, silk produced at speeds outside this natural processing window has a different microstructure that leads to inferior tensile properties. Moreover, we also show that the silk has a generic microstructure that is optimized to respond mechanically to deformation such that the crystals in the fibers are deformed under conditions of uniform strain. This is different from high-performance synthetic polymer fibers where the microstructure is optimized such that crystals within the fibers are subjected to uniform stress. Graphic abstract

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Ultrafine and High-Strength Silk Fibers Secreted by Bimolter Silkworms

Polymers ◽

10.3390/polym12112537 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2537 ◽

Cited By ~ 1

Author(s):

Kaiyu Guo ◽

Xiaolu Zhang ◽

Zhaoming Dong ◽

Yuhui Ni ◽

Yuqing Chen ◽

...

Keyword(s):

Mechanical Properties ◽

High Performance ◽

High Strength ◽

Silk Gland ◽

X Ray Diffraction ◽

Ultrafine Fibers ◽

Silk Fibers ◽

Warmth Retention ◽

The Relationship ◽

Β Sheet

Ultrafine fibers are widely employed because of their lightness, softness, and warmth retention. Although silkworm silk is one of the most applied natural silks, it is coarse and difficult to transform into ultrafine fibers. Thus, to obtain ultrafine high-performance silk fibers, we employed anti-juvenile hormones in this study to induce bimolter silkworms. We found that the bimolter cocoons were composed of densely packed thin fibers and small apertures, wherein the silk diameter was 54.9% less than that of trimolter silk. Further analysis revealed that the bimolter silk was cleaner and lighter than the control silk. In addition, it was stronger (739 MPa versus 497 MPa) and more stiffness (i.e., a higher Young’s modulus) than the trimolter silk. FTIR and X-ray diffraction results revealed that the excellent mechanical properties of bimolter silk can be attributed to the higher β-sheet content and crystallinity. Chitin staining of the anterior silk gland suggested that the lumen is narrower in bimolters, which may lead to the formation of greater numbers of β-sheet structures in the silk. Therefore, this study reveals the relationship between the structures and mechanical properties of bimolter silk and provides a valuable reference for producing high-strength and ultrafine silk fibers.

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Hybrid Spider Silk with Inorganic Nanomaterials

Nanomaterials ◽

10.3390/nano10091853 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1853

Author(s):

Aleksandra P. Kiseleva ◽

Grigorii O. Kiselev ◽

Valeria O. Nikolaeva ◽

Gulaim Seisenbaeva ◽

Vadim Kessler ◽

...

Keyword(s):

Hybrid Materials ◽

High Performance ◽

Spider Silk ◽

Inorganic Compounds ◽

Silk Fibers ◽

Surface Areas ◽

Macro Scale ◽

Performance Functional ◽

Inorganic Nanomaterials ◽

Functional Components

High-performance functional biomaterials are becoming increasingly requested. Numerous natural and artificial polymers have already demonstrated their ability to serve as a basis for bio-composites. Spider silk offers a unique combination of desirable aspects such as biocompatibility, extraordinary mechanical properties, and tunable biodegradability, which are superior to those of most natural and engineered materials. Modifying spider silk with various inorganic nanomaterials with specific properties has led to the development of the hybrid materials with improved functionality. The purpose of using these inorganic nanomaterials is primarily due to their chemical nature, enhanced by large surface areas and quantum size phenomena. Functional properties of nanoparticles can be implemented to macro-scale components to produce silk-based hybrid materials, while spider silk fibers can serve as a matrix to combine the benefits of the functional components. Therefore, it is not surprising that hybrid materials based on spider silk and inorganic nanomaterials are considered extremely promising for potentially attractive applications in various fields, from optics and photonics to tissue regeneration. This review summarizes and discusses evidence of the use of various kinds of inorganic compounds in spider silk modification intended for a multitude of applications. It also provides an insight into approaches for obtaining hybrid silk-based materials via 3D printing.

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Achieving high-performance epoxy nanocomposites with trifunctional poly(oxypropylene)amines functionalized graphene oxide

High Performance Polymers ◽

10.1177/0954008319832353 ◽

2019 ◽

Vol 31 (5) ◽

pp. 557-569 ◽

Cited By ~ 3

Author(s):

Tong Sun ◽

Huawei Zou ◽

Ya Zhou ◽

Rui Li ◽

Mei Liang ◽

...

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

High Performance ◽

Flexural Modulus ◽

Covalent Bonds ◽

Spectra Analysis ◽

Functionalized Graphene Oxide ◽

Ep Matrix ◽

Functional Graphene Oxide ◽

The Relationship

In this article, two types of functional graphene oxide (GO) with amine-rich surface were synthesized through chemically grafting two different molecular chain length trifunctional poly(oxypropylene)amines T5000 and T403, which were named as T5000-GO and T403-GO, respectively. The functionalized GO was then added to epoxy (EP) resin. Fourier transform infrared spectra analysis confirmed successful chemical functionalization on GO. Both T403-GO and T5000-GO were tightly embedded in the EP, because the amine-rich surface of functionalized-GO could form covalent bonds with the EP matrix, thereby contributing to the enhancement of mechanical properties. Particularly, T5000-GO, which has longer grafting molecule chains, achieved better compatibility and dispersibility in the EP matrix, resulting in a better reinforcing efficiency in mechanical properties. For example, the T5000-GO/EP composites showed an incremental enhancement in tensile strength with increasing filler concentrations, whereas their T403-GO/EP counterparts failed to follow the same trend. Meanwhile, the T5000-GO/EP composites with only 0.1-wt% T5000-GO achieved a prominent increase in flexural strength (approximately 50%) and flexural modulus (approximately 26.8%), which were higher than those of T403-GO-filled counterparts. This work indicated that the compatibility and interphase between GO and EP could be designed by manipulating the length of grafting molecule chains, thereby providing a better understanding of the relationship between the structure and mechanical properties of the graphene/EP nanocomposites.

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Mechanical properties and application analysis of spider silk bionic material

e-Polymers ◽

10.1515/epoly-2020-0049 ◽

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.

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Value-Engineering Methodology for the Selection of an Optimal Bridge System

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211062154 ◽

2021 ◽

pp. 036119812110621

Author(s):

Ahmad A. Mousa ◽

Mohab Hussein ◽

Ahmed Farouk Kineber

Keyword(s):

Life Cycle Cost ◽

High Performance ◽

Function Analysis ◽

Decision Makers ◽

Value Engineering ◽

Original Design ◽

Long Span ◽

Long Span Bridge ◽

Selection Of ◽

Bridge System

Maintaining and enhancing the functionality of the infrastructure at an affordable cost are major challenges for decision makers, particularly given the need to cope with growing societal and transportation demands. This study introduces a systematic multi-criteria value engineering (VE) approach for the selection of a sustainable bridge system. A thorough VE analysis for a proposed long-span bridge in New Jersey, USA was carried out as a pilot study. The function analysis system technique was used to develop logical relationships between the project’s functions. A detailed 100-year life-cycle cost analysis (LCCA) was conducted. The study developed and evaluated eight alternative designs for deck and superstructure systems against set VE criteria comprising constructability, maintenance strategies, and environmental impact. A relative value index was used as an unbiased measure for the selection of the optimal structural system. With total savings of approximately 21% of the original design ($132.5 million), steel plate girders with a high-performance lightweight steel grid deck system have proven to “outvalue” the other alternatives, including the preferred preliminary alternative (PPA). Design engineers and decision makers can use this methodology as a systematic and convenient guide for the selection of economical and sustainable bridge systems. As such, it is necessary to re-evaluate the current practices and policies used for this purpose.

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Dyeing and Mechanical Properties of Cotton Modified for Cationic Dyes with Hydrophobic and Acidic Groups

Textile Research Journal ◽

10.1177/004051759206200303 ◽

1992 ◽

Vol 62 (3) ◽

pp. 135-139 ◽

Cited By ~ 2

Author(s):

Kazuhiko Fukatsu

Keyword(s):

Mechanical Properties ◽

General Trend ◽

Breaking Load ◽

Cationic Dyes ◽

Superior Performance ◽

Chemically Modified ◽

Basic Studies ◽

The Relationship ◽

Sulfonic Acid Groups ◽

Selection Of

Basic studies define the relationship between dyeability for cationic dyes and mechanical properties of chemically modified cotton fabric. Introduction of benzoyl and sulfonic acid groups provides either satisfactory dyeability for cationic dyes or color-fastness, and mechanical properties are reported as a function of the benzoate degree of substitution value. The general trend is toward increased breaking load and bending stiffness and decreased wrinkle recovery for the chemically modified fabrics, but within this trend there is latitude for selection of the degree of substituent groups to provide superior performance.

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

Soft Matter ◽

10.1039/c2sm25446h ◽

2012 ◽

Vol 8 (22) ◽

pp. 6015 ◽

Cited By ~ 61

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

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Hydrothermal Effect on Mechanical Properties of Nephila pilipes Spidroin

Polymers ◽

10.3390/polym12051013 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1013 ◽

Cited By ~ 1

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.

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Development of a Computer Tool to Support the Teaching of Materials Technology

Materials Science Forum ◽

10.4028/www.scientific.net/msf.903.17 ◽

2017 ◽

Vol 903 ◽

pp. 17-23 ◽

Cited By ~ 3

Author(s):

Álvaro Rodríguez-Prieto ◽

Ana Maria Camacho ◽

Miguel Ángel Sebastián

Keyword(s):

Mechanical Properties ◽

Nuclear Reactor ◽

Pressure Vessels ◽

Computer Tool ◽

Materials Engineering ◽

Service Behavior ◽

Stringency Level ◽

The Relationship ◽

Selection Of

Materials technology is a matter of great applicative and crosscutting interest, as evidenced by their presence in most curriculums of the current industrial engineering degrees. During the development of this matter, it is crucial that the student assimilates not only the relationship among composition, processing and mechanical properties, but also, how all these technological features interact facing the in-service behavior of the material. That is why, within a Doctoral dissertation developed at the Department of Construction and Manufacturing Engineering at the National Distance Education University (UNED), it has designed a computer tool to quantify the stringency level of technological requirements of materials (especially suitable for high demanding applications), characterized by its suitability as interactive teaching material used in the teaching of materials engineering. As a case study, we have chosen a selection of materials for nuclear reactor pressure vessels, because it is a very representative example of the relationship between chemical composition, mechanical properties and in-service behavior.

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