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

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 spinn...

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Autores principales: Wu, Hsuan-Chen, Wu, Shang-Ru, Yang, Thomas Chung-Kuang, Yang, Jen-Chang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213051/
https://www.ncbi.nlm.nih.gov/pubmed/30321988
http://dx.doi.org/10.3390/ma11101951
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author Wu, Hsuan-Chen
Wu, Shang-Ru
Yang, Thomas Chung-Kuang
Yang, Jen-Chang
author_facet Wu, Hsuan-Chen
Wu, Shang-Ru
Yang, Thomas Chung-Kuang
Yang, Jen-Chang
author_sort Wu, Hsuan-Chen
collection PubMed
description 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.
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spelling pubmed-62130512018-11-14 A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning Wu, Hsuan-Chen Wu, Shang-Ru Yang, Thomas Chung-Kuang Yang, Jen-Chang Materials (Basel) Article 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. MDPI 2018-10-12 /pmc/articles/PMC6213051/ /pubmed/30321988 http://dx.doi.org/10.3390/ma11101951 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Wu, Hsuan-Chen
Wu, Shang-Ru
Yang, Thomas Chung-Kuang
Yang, Jen-Chang
A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning
title A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning
title_full A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning
title_fullStr A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning
title_full_unstemmed A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning
title_short A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning
title_sort facile measurement for monitoring dragline silk dope concentration in nephila pilipes upon spinning
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213051/
https://www.ncbi.nlm.nih.gov/pubmed/30321988
http://dx.doi.org/10.3390/ma11101951
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