scholarly journals A New Evidence of Lubrication Hypothesis on Nephila pilipes Spider Silk Spinning

2017 ◽  
Author(s):  
Hsuan-Chen Wu ◽  
Shang-Ru Wu ◽  
Jen-Chang Yang
Keyword(s):  
Spider Silk ◽  
Fiber Diameter ◽  
Underlying Mechanism ◽  
Silk Fibers ◽  
Novel Approach ◽  
Lubrication Layer ◽  
Spinning Process ◽  
Spun Fiber ◽  
Material Fabrication ◽  
New Evidence

In spite of all the efforts on deciphering such spinning process of spiders, the underlying mechanism currently is yet to be fully revealed. In this research, we designed a novel approach to quantitatively estimate the overall concentration change of spider silk along the progression of liquid-to-solid silk transition from the gland silk. As a prior characterization, we first studied the influence of silking-rate, ranged from 1.5 to 8.0 m/min, on spun fiber diameters as well as fiber strengths. Furthermore, the liquid contents of silk in the sac and the silk fibers leaving the spinneret were investigated by thermogravimetric analysis (TGA) and by estimating the ratio of collected dried silk to the weight loss of spider, respectively. The strength of spun silk fiber showed in the range of 7.5 - 8.5 g/denier; while, the fiber diameter of 0.7 - 1.1 deniers for spun silk first increased then decreased with take-up speed of winder. The results showed that the percentage liquid content of silk stored in the major ampullate sac (50.0 wt%) was lower than that of silk leaving the spinnerets (80.9 - 96.1 wt%), indicating a liquid supplying mechanism might be involved during the spinning process. Thus, a hypothesis of liquid coating on the outer surface of the silk thread served as a lubrication layer to reduce the silking resistance in spinning spigot of spider was proposed. In addition, we speculated the spigot serves as a valve-like regulator that controls not only the fiber diameter but also the lubrication layer. These findings provide understanding in physiological function of the spider spinning process and could further shed some light on future biomimetic development of silk material fabrication.

scholarly journals A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1951 ◽  
Author(s):  
Hsuan-Chen Wu ◽  
Shang-Ru Wu ◽  
Thomas Yang ◽  
Jen-Chang Yang
Keyword(s):  
Underlying Mechanism ◽  
Solid Content ◽  
Fiber Formation ◽  
Liquid Content ◽  
Dragline Silk ◽  
Quantitative Evidence ◽  
Novel Approach ◽  
Spinning Process ◽  
Material Fabrication ◽  
First Time

In spite of all the efforts towards deciphering the silk spinning process of spiders, the underlying mechanism is yet to be fully revealed. In this research, we designed a novel approach that allowed us to quantitatively evaluate the concentration change of silk dope during the liquid-to-solid spinning process of the orb-weaver Nephila pilipes. As a prior characterization of the optimal silking conditions, we first gauged the influence of silking-rate, ranging from 1.5 to 8.0 m/min, on dragline silk diameters and silk tensile strengths obtained from the spiders. Next, to evaluate the liquid content of the silk dope, the major ampullate gland was dissected and the concentration of the sac portion was measured by thermogravimetric analysis (TGA). The solid content of the dragline fibers leaving the spinneret was investigated by calculating the ratio of collected dried silk to the weight loss of the spider recorded in situ upon spinning. As the results indicate, the tensile strength and diameter of the spun dragline fibers were 800–1100 MPa and 8–11 μm, respectively. The liquid content of silk stored in the major ampullate sac (50.0 wt%) was significantly lower than that of silk leaving the spinnerets (80.9–96.1 wt%), indicating that a liquid supplying mechanism might be involved during the spinning process. This reveals, for the first time, quantitative evidence in support of the lubricative hypothesis proposed formerly, namely that a liquid coating layer is supplemented to compensate for silking resistance during the spinning process of a spider. The spigot, at the exit of the spinneret, is speculated to serve as a valve-like controller that regulates the lubrication process along with fiber formation. Taken together, these findings provide understanding of the physiological functions in the spider spinning process and could further shed some light on the future biomimetic development of silk material fabrication.

Tough synthetic spider-silk fibers obtained by titanium dioxide incorporation and formaldehyde cross-linking in a simple wet-spinning process

Biochimie ◽  
2020 ◽  
Vol 175 ◽  
pp. 77-84
Author(s):  
Hongnian Zhu ◽  
Yuan Sun ◽  
Tuo Yi ◽  
Suyang Wang ◽  
Junpeng Mi ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Spider Silk ◽  
Wet Spinning ◽  
Cross Linking ◽  
Silk Fibers ◽  
Spinning Process

scholarly journals Silk-based antimicrobial peptide mixed with recombinant spidroin creates functionalized spider silk

2021 ◽  
Author(s):  
Frank Y.C. Liu
Keyword(s):  
Antimicrobial Peptide ◽  
Spider Silk ◽  
Antimicrobial Properties ◽  
Beta Sheets ◽  
Silk Fibers ◽  
E Coli ◽  
Log Reduction ◽  
Spider Silk Protein ◽  
Spinning Process ◽  
Recombinant Spidroin

Surgical site infection (SSI) from sutures is a global health emergency because of the antibiotic crisis. Methicillin-resistant S. aureus and other emerging strains are difficult to treat with antibiotics, so drug-free sutures with antimicrobial properties are a solution. Functionalized spider silk protein (spidroin) is a candidate for its extraordinary strength because it has a large repetitive region (150Rep) that forms crosslinked beta-sheets. The antimicrobial peptide HNP-1 can be connected to recombinant spidroin to create antimicrobial silk. Ni-NTA purified 2Rep-HNP1 fusion protein was mixed with recombinant NT2RepCT spidroin at 1:25, 1:20, 1:10 ratios, and spun into silk fibers by syringe-pumping protein into a 100% isopropanol bath. Beta-sheet crosslinking of the identical 2Rep regions tagged the 2Rep-HNP1 permanently onto the resultant silk. Silk showed no sign of degradation in an autoclave, PBS, or EtOH. The tagged 2Rep-HNP1 retained broad-spectrum antimicrobial activity >90% against S. aureus and E. coli as measured by log reduction and radial diffusion assay. Furthermore, a modified expression protocol increased protein yield of NT2RepCT 2.8-fold, and variable testing of the spinning process demonstrated the industrial viability of silk production. We present a promising suture alternative in antimicrobial recombinant spider silk.

High‐toughness Spider Silk Fibers Spun from Soluble Recombinant Silk Produced in Mammalian Cells

2003 ◽  
Author(s):  
Costas N. Karatzas ◽  
Nathalie Chretien ◽  
François Duguay ◽  
Annie Bellemare ◽  
Jiang Feng Zhou ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Spider Silk ◽  
Silk Fibers ◽  
High Toughness

scholarly journals Cribellate thread production as model for spider’s spinneret kinematics

2021 ◽  
Author(s):  
Margret Weissbach ◽  
Marius Neugebauer ◽  
Anna-Christin Joel
Keyword(s):  
Molecular Structure ◽  
Mechanical Properties ◽  
Fibre Type ◽  
Material Science ◽  
Spider Silk ◽  
Functional Unit ◽  
Material Strength ◽  
Spinning Process ◽  
Fibre Spinning ◽  
House Spider

AbstractSpider silk attracts researchers from the most diverse fields, such as material science or medicine. However, still little is known about silk aside from its molecular structure and material strength. Spiders produce many different silks and even join several silk types to one functional unit. In cribellate spiders, a complex multi-fibre system with up to six different silks affects the adherence to the prey. The assembly of these cribellate capture threads influences the mechanical properties as each fibre type absorbs forces specifically. For the interplay of fibres, spinnerets have to move spatially and come into contact with each other at specific points in time. However, spinneret kinematics are not well described though highly sophisticated movements are performed which are in no way inferior to the movements of other flexible appendages. We describe here the kinematics for the spinnerets involved in the cribellate spinning process of the grey house spider, Badumna longinqua, as an example of spinneret kinematics in general. With this information, we set a basis for understanding spinneret kinematics in other spinning processes of spiders and additionally provide inspiration for biomimetic multiple fibre spinning.

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

Tapping the Power of Social Media on Innovation Performance

2021 ◽  
Vol 9 (2) ◽  
pp. 143-151
Author(s):  
Shan Shan Teh ◽  
Daisy Mui Hung Kee ◽  
Munazza Zahra ◽  
Gadi Dung Paul
Keyword(s):  
Social Media ◽  
Data Collection ◽  
Open Innovation ◽  
Underlying Mechanism ◽  
Jel Classification ◽  
Innovation Performance ◽  
Great Idea ◽  
New Evidence ◽  
The Relationship ◽  
Innovation Impact

Objective - This study investigates the relationship between social media and innovation performance among SMEs in Malaysia. This study also extends social media literature by investigating the underlying mechanism of open innovation in the relationship between social media and innovation performance. Methodology/Technique - A questionnaire was used to collect data from the respondents. A total of 173 samples from data collection were then used to test the hypotheses by using the SPSS and SmartPLS software. Finding - The result has revealed that social media has a significant effect on innovation performance. Besides, outbound innovation is also found to mediate the relationship between social media and innovation performance. Novelty - This study contributes to the literature on social media and innovation by providing new evidence regarding outbound innovation impact on performance among SMEs. It also provides a great idea of social media's importance to SME managers in improving innovation performance in an organization. Type of Paper - Empirical. Keywords: Social Media, Innovation Performance, Open Innovation, Smes, Malaysia JEL Classification: URI: http://gatrenterprise.com/GATRJournals/GJBSSR/vol9.2_4.html DOI: https://doi.org/10.35609/gjbssr.2021.9.2(4) Pages 143 – 151

Water-tunnel studies of heat balance in swimming mako sharks

2001 ◽  
Vol 204 (23) ◽  
pp. 4043-4054 ◽  
Author(s):  
Diego Bernal ◽  
Chugey Sepulveda ◽  
Jeffrey B. Graham
Keyword(s):  
Heat Transfer ◽  
Heat Balance ◽  
Underlying Mechanism ◽  
The Body ◽  
Morphological Properties ◽  
Water Tunnel ◽  
Vascular Networks ◽  
Red Muscle ◽  
Counter Current ◽  
New Evidence

SUMMARY The mako shark (Isurus oxyrinchus) has specialized vascular networks (retia mirabilia) forming counter-current heat exchangers that allow metabolic heat retention in certain regions of the body, including the aerobic, locomotor red muscle and the viscera. Red muscle, white muscle and stomach temperatures were measured in juvenile (5–13.6 kg) makos swimming steadily in a water tunnel and exposed to stepwise square-wave changes in ambient temperature (Ta) to estimate the rates of heat transfer and to determine their capacity for the activity-independent control of heat balance. The rates of heat gain of red muscle during warming were significantly higher than the rates of heat loss during cooling, and neither the magnitude of the change in Ta nor the direction of change in Ta had a significant effect on red muscle latency time. Our findings for mako red muscle are similar to those recorded for tunas and suggest modulation of retial heat-exchange efficiency as the underlying mechanism controlling heat balance. However, the red muscle temperatures measured in swimming makos (0.3–3°C above Ta) are cooler than those measured previously in larger decked makos. Also, the finding of non-stable stomach temperatures contrasts with the predicted independence from Ta recorded in telemetry studies of mako and white sharks. Our studies on live makos provide new evidence that, in addition to the unique convergent morphological properties between makos and tunas, there is a strong functional similarity in the mechanisms used to regulate heat transfer.

scholarly journals Hierarchical spidroin micellar nanoparticles as the fundamental precursors of spider silks

2018 ◽  
Vol 115 (45) ◽  
pp. 11507-11512 ◽  
Author(s):  
Lucas R. Parent ◽  
David Onofrei ◽  
Dian Xu ◽  
Dillan Stengel ◽  
John D. Roehling ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Spider Silk ◽  
Fiber Spinning ◽  
Fiber Formation ◽  
Natural Material ◽  
Physical Form ◽  
Spinning Process ◽  
Black Widow Spiders ◽  
Spider Silks

Many natural silks produced by spiders and insects are unique materials in their exceptional toughness and tensile strength, while being lightweight and biodegradable–properties that are currently unparalleled in synthetic materials. Myriad approaches have been attempted to prepare artificial silks from recombinant spider silk spidroins but have each failed to achieve the advantageous properties of the natural material. This is because of an incomplete understanding of the in vivo spidroin-to-fiber spinning process and, particularly, because of a lack of knowledge of the true morphological nature of spidroin nanostructures in the precursor dope solution and the mechanisms by which these nanostructures transform into micrometer-scale silk fibers. Herein we determine the physical form of the natural spidroin precursor nanostructures stored within spider glands that seed the formation of their silks and reveal the fundamental structural transformations that occur during the initial stages of extrusion en route to fiber formation. Using a combination of solution phase diffusion NMR and cryogenic transmission electron microscopy (cryo-TEM), we reveal direct evidence that the concentrated spidroin proteins are stored in the silk glands of black widow spiders as complex, hierarchical nanoassemblies (∼300 nm diameter) that are composed of micellar subdomains, substructures that themselves are engaged in the initial nanoscale transformations that occur in response to shear. We find that the established micelle theory of silk fiber precursor storage is incomplete and that the first steps toward liquid crystalline organization during silk spinning involve the fibrillization of nanoscale hierarchical micelle subdomains.

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