Description of Test Setup and Approach to Measure Thermal Properties of Natural and Synthetic Spider Silks at Cryogenic Temperatures

2013 ◽  
Author(s):  
Troy Munro ◽  
Changhu Xing ◽  
Andrew Marquette ◽  
Heng Ban ◽  
Cameron Copeland ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Conformational Changes ◽  
Spider Silk ◽  
Protein Structures ◽  
Cryogenic Temperatures ◽  
Nephila Clavipes ◽  
Silk Fibers ◽  
Spider Silks ◽  
Better Than ◽  
Natural And Synthetic

Spider silk is well-known for its exceptional mechanical properties, such as strength, elasticity and flexibility. Recently, it has been reported that dragline silk from a Nephila clavipes also has an exceptionally high thermal conductivity, comparable to copper when the fiber is stretched. Synthetic spider silks have been spun from spider silk proteins produced in transgenic sources, and their production process has the optimization potential to have properties similar to or better than the natural spider silk. There is interest to measure the thermal properties of natural and synthetic silk at cryogenic temperatures for use of spider silk fibers as heat conduits in systems where component weight is an issue, such as in spacecraft. This low temperature measurement is also of particular interest because of the conformational changes in protein structures, which affect material properties, that occurs at lower temperatures for some proteins. A measurement system has been designed and is being tested to characterize the thermal properties of natural and synthetic spider silks by means of a transient electrothermal method.

scholarly journals Nephila clavipes Flagelliform Silk-Like GGX Motifs Contribute to Extensibility and Spacer Motifs Contribute to Strength in Synthetic Spider Silk Fibers

2013 ◽  
Vol 14 (6) ◽  
pp. 1751-1760 ◽  
Author(s):  
Sherry L. Adrianos ◽  
Florence Teulé ◽  
Michael B. Hinman ◽  
Justin A. Jones ◽  
Warner S. Weber ◽  
...  
Keyword(s):  
Spider Silk ◽  
Nephila Clavipes ◽  
Silk Fibers

scholarly journals Spidroins and Silk Fibers of Aquatic Spiders

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sandra M. Correa-Garhwal ◽  
Thomas H. Clarke ◽  
Marc Janssen ◽  
Luc Crevecoeur ◽  
Bryce N. McQuillan ◽  
...  
Keyword(s):  
Gene Family ◽  
Spider Silk ◽  
Silk Gland ◽  
Aquatic Environments ◽  
Rna Seq ◽  
Silk Fibers ◽  
Fibroin Gene ◽  
Terrestrial Environments ◽  
Orb Web ◽  
Spider Silks

Abstract Spiders are commonly found in terrestrial environments and many rely heavily on their silks for fitness related tasks such as reproduction and dispersal. Although rare, a few species occupy aquatic or semi-aquatic habitats and for them, silk-related specializations are also essential to survive in aquatic environments. Most spider silks studied to date are from cob-web and orb-web weaving species, leaving the silks from many other terrestrial spiders as well as water-associated spiders largely undescribed. Here, we characterize silks from three Dictynoidea species: the aquatic spiders Argyroneta aquatica and Desis marina as well as the terrestrial Badumna longinqua. From silk gland RNA-Seq libraries, we report a total of 47 different homologs of the spidroin (spider fibroin) gene family. Some of these 47 spidroins correspond to known spidroin types (aciniform, ampullate, cribellar, pyriform, and tubuliform), while other spidroins represent novel branches of the spidroin gene family. We also report a hydrophobic amino acid motif (GV) that, to date, is found only in the spidroins of aquatic and semi-aquatic spiders. Comparison of spider silk sequences to the silks from other water-associated arthropods, shows that there is a diversity of strategies to function in aquatic environments.

Anisotropic nanomechanical properties of Nephila clavipes dragline silk

2006 ◽  
Vol 21 (8) ◽  
pp. 2035-2044 ◽  
Author(s):  
Donna M. Ebenstein ◽  
Kathryn J. Wahl
Keyword(s):  
Mechanical Properties ◽  
Spider Silk ◽  
Imaging Techniques ◽  
Dynamic Stiffness ◽  
Longitudinal Section ◽  
Mechanical Anisotropy ◽  
Nephila Clavipes ◽  
Silk Fibers ◽  
Reduced Modulus ◽  
Anisotropic Mechanical Properties

Spider silk is a material with unique mechanical properties under tension. In this study, we explore the anisotropic mechanical properties of spider silk using instrumented indentation. Both quasistatic indentation and dynamic stiffness imaging techniques were used to measure the mechanical properties in transverse and longitudinal sections of silk fibers. Quasistatic indentation yielded moduli of 10 ± 2 GPa in transverse sections and moduli of 6.4 ± 0.5 GPa in longitudinal sections, demonstrating mechanical anisotropy in the fiber. This result was supported by dynamic stiffness imaging, which also showed the average reduced modulus measured in the transverse section to be slightly higher than that of the longitudinal section. Stiffness imaging further revealed an oriented microstructure in the fiber, showing microfibrils aligned with the drawing axis of the fiber. No spatial distribution of modulus across the silk sections was observed by either quasistatic or stiffness imaging mechanics.

Nephila Clavipes Dragline Silk: Approaches to a Recombinantly Produced Silk Protein

1993 ◽  
Vol 330 ◽  
Author(s):  
Charlene M. Mello ◽  
Steven Arcidiacono ◽  
Richard Beckwitt ◽  
John Prince ◽  
Kris Senecal ◽  
...  
Keyword(s):  
High Performance ◽  
Spider Silk ◽  
Recombinant Dna ◽  
Electromagnetic Spectrum ◽  
Nephila Clavipes ◽  
Natural Function ◽  
High Performance Fiber ◽  
Recombinant Dna Techniques ◽  
Clone And Express ◽  
Spider Silks

Spider silks exhibit an unusual combination of strength and toughness that distinguishes them from other natural and synthetic fibers. Silk proteins perform a key natural function as structural fibers, to absorb impact energy from flying insects without breaking. They dissipate energy over a broad area and balance stiffness, strength and extensibility (1,2). In addition to their unusual mechanical properties and visual lustre, silks also exhibit interesting interference patterns within the electromagnetic spectrum (3), unusual viscometric patterns related to processing (4), and piezoelectric properties (3,5,6). These properties suggest they would be good candidates for high performance fiber and composite applications. However, the spider is not capable of producing sufficient quantities of proteins to enable thorough evaluation of their potential. Consequently, we are pursuing recombinant DNA techniques to clone and express adequate quantities of recombinant spider silk for these studies.

scholarly journals Spider silk colour covaries with thermal properties but not protein structure

2019 ◽  
Vol 16 (156) ◽  
pp. 20190199 ◽  
Author(s):  
Sean J. Blamires ◽  
Georgia Cerexhe ◽  
Thomas E. White ◽  
Marie E. Herberstein ◽  
Michael M. Kasumovic
Keyword(s):  
Thermal Properties ◽  
Protein Structure ◽  
Spider Silk ◽  
Protein Structures ◽  
Ecological Factors ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Protein Uptake

Understanding how and why animal secretions vary in property has important biomimetic implications as desirable properties might covary. Spider major ampullate (MA) silk, for instance, is a secretion earmarked for biomimetic applications, but many of its properties vary among and between species across environments. Here, we tested the hypothesis that MA silk colour, protein structure and thermal properties covary when protein uptake is manipulated in the spider Trichonephila plumipes . We collected silk from adult female spiders maintained on a protein-fed or protein-deprived diet. Based on spectrophotometric quantifications, we classified half the silks as ‘bee visible’ and the other half ‘bee invisible’. Wide angle X-ray diffraction and differential scanning calorimetry were then used to assess the silk's protein structure and thermal properties, respectively. We found that although protein structures and thermal properties varied across our treatments only the thermal properties covaried with colour. This ultimately suggests that protein structure alone is not responsible for MA silk thermal properties, nor does it affect silk colours. We speculate that similar ecological factors act on silk colour and thermal properties, which should be uncovered to inform biomimetic programmes.

Probing the Mysteries of Spider Silk’s Uncharacteristically High Thermal Diffusivity

2013 ◽  
Author(s):  
Troy Munro ◽  
Changhu Xing ◽  
Heng Ban ◽  
Cameron Copeland ◽  
Randolph Lewis
Keyword(s):  
Thermal Properties ◽  
Protein Content ◽  
Spider Silk ◽  
Gold Film ◽  
Milk Proteins ◽  
Initial Study ◽  
Silk Proteins ◽  
Fundamental Understanding ◽  
High Thermal Diffusivity ◽  
Spider Silks

Spider silks exhibit excellent strength, stiffness, and toughness simultaneously, a feat unachievable in most synthetic, structural materials. It has recently been reported that the thermal conductivity of dragline silk is comparable to copper, which is uncharacteristically high for a biomaterial. In order to develop a fundamental understanding of the high thermal properties of spider silk, further research must be made to explore how the structure and organization of spider silk proteins affects heat transfer characteristics. Synthetically produced silks created from spider silk proteins obtained from transgenic sources can be used to determine these protein structure effects by varying protein content and process treatments. This initial study determined the thermal properties of synthetic spider silk created from transgenic goat’s milk proteins using the transient electrothermal method (TET). Results show that the thermal properties of the synthetic silk are lower than the natural spider silk but vary based on the process treatment, and that the annealing of the gold film coated on the fiber has no effect on the measured thermal properties. These results provide a framework for further research on the protein content effect and its role in thermal properties.

scholarly journals Photoreflectance/scattering measurements of spider silks informed by standard optics

2020 ◽  
Vol 7 (4) ◽  
pp. 192174
Author(s):  
Sean J. Blamires ◽  
Douglas J. Little ◽  
Thomas E. White ◽  
Deb M. Kane
Keyword(s):  
Optical Properties ◽  
Optical Materials ◽  
Spider Silk ◽  
Nephila Clavipes ◽  
Optical Elements ◽  
Scattering Spectrum ◽  
Modern Species ◽  
Uv Reflectance ◽  
Argiope Keyserlingi ◽  
Spider Silks

The silks of certain orb weaving spiders are emerging as high-quality optical materials. This motivates study of the optical properties of such silk and particularly the comparative optical properties of the silks of different species. Any differences in optical properties may impart biological advantage for a spider species and make the silks interesting for biomimetic prospecting as optical materials. A prior study of the reflectance of spider silks from 18 species reported results for three species of modern orb weaving spiders ( Nephila clavipes, Argiope argentata and Micrathena Schreibersi ) as having reduced reflectance in the UV range. (Modern in the context used here means more recently derived.) The reduced UV reflectance was interpreted as an adaptive advantage in making the silks less visible to insects. Herein, a standard, experimental technique for measuring the reflectance spectrum of diffuse surfaces, using commercially available equipment, has been applied to samples of the silks of four modern species of orb weaving spiders: Phonognatha graeffei , Eriophora transmarina , Nephila plumipes and Argiope keyserlingi . This is a different technique than used in the previous study. Three of the four silks measured have a reduced signal in the UV. By taking the form of the silks as optical elements into account, it is shown that this is attributable to a combination of wavelength-dependent absorption and scattering by the silks rather than differences in reflectance for the different silks. Phonognatha graeffei dragline silk emerges as a very interesting spider silk with a flat ‘reflectance'/scattering spectrum which may indicate it is a low UV absorbing dielectric micro-fibre. Overall the measurement emerges as having the potential to compare the large numbers of silks from different species to prospect for those which have desirable optical properties.

Automated Assessment of Binding Affinity via Alchemical Free Energy Calculations

2020 ◽  
Author(s):  
Maximilian Kuhn ◽  
Stuart Firth-Clark ◽  
Paolo Tosco ◽  
Antonia S. J. S. Mey ◽  
Mark Mackey ◽  
...  
Keyword(s):  
Free Energy ◽  
Protein Structures ◽  
Free Energy Calculations ◽  
Distinct Advantage ◽  
Binding Affinities ◽  
Structure Based Drug Design ◽  
Energy Calculations ◽  
Kendall’S Τ ◽  
Experimental Values ◽  
Better Than

Free energy calculations have seen increased usage in structure-based drug design. Despite the rising interest, automation of the complex calculations and subsequent analysis of their results are still hampered by the restricted choice of available tools. In this work, an application for automated setup and processing of free energy calculations is presented. Several sanity checks for assessing the reliability of the calculations were implemented, constituting a distinct advantage over existing open-source tools. The underlying workflow is built on top of the software Sire, SOMD, BioSimSpace and OpenMM and uses the AMBER14SB and GAFF2.1 force fields. It was validated on two datasets originally composed by Schrödinger, consisting of 14 protein structures and 220 ligands. Predicted binding affinities were in good agreement with experimental values. For the larger dataset the average correlation coefficient Rp was 0.70 ± 0.05 and average Kendall’s τ was 0.53 ± 0.05 which is broadly comparable to or better than previously reported results using other methods. <br>

Sign in / Sign up

Export Citation Format

Share Document