Biophysicist Irina Iashina, University of Southern Denmark, holds silk fibers produced by a golden web spider. Credit: Anders Boe/University of Southern Denmark
Many scientists aspire to discover the spider’s extraordinary ability to spin extremely strong, light and flexible silk threads. In fact, spider silk is stronger than steel and tougher than Kevlar. However, no one has been able to imitate the work of these spiders.
If we could develop synthetic materials equivalent to these properties, this could open up new possibilities: synthetic spider silk could replace materials such as Kevlar, polyester and carbon fiber in industry, and could be used, for example, to make lightweight materials. . and flexible products. Bulletproof jacket.
Irina Iashina, postdoctoral researcher and biophysicist from the Department of Biochemistry and Molecular Biology at the University of Southern Denmark (SDU), participated in the race to uncover the recipe for supersilk. He has been fascinated with spider silk since he was a master’s student at SDU, and is currently researching the topic at the Massachusetts Institute of Technology in Boston with support from the Velome Foundation.
Biophysicist Irina Iashina, University of Southern Denmark, studies spider silk on a computer. Credit: Anders Boe/University of Southern Denmark
As part of his research, he collaborated with SDU assistant professor and biophysicist Jonathan Brewer, an expert in using various types of microscopes to view biological structures.
Together they have now, for the first time, studied the inside of spider silk using an optical microscope without cutting or opening the silk in any way. This work has now been published in the journal Scientific report And Scan is complete.
“We used some advanced microscope techniques, and we also developed a new type of optical microscope that allows us to look at a piece of fiber and see what’s inside,” explains Jonathan Brewer.
The golden orb web spider produces its silk from its rear end. Credit: Anders Boe/University of Southern Denmark
To date, spider silk has been analyzed using different techniques, all of which provide new insights. However, there are also drawbacks to this technique, as Jonathan Brewer points out, as it often requires cutting silk threads (also known as fibres) open to obtain cross sections for microscopy or freezing the sample, which can change its structure. silk fiber.
“We wanted to study pure fiber that is unprocessed and has not been cut, frozen or processed in any way,” said Irina Iashina.
For this purpose, the research duo used less invasive techniques such as Coherent Anti-Stokes Raman Scattering, confocal microscopy, super-resolution fluorescence reflectance confocal microscopy, helium ion scanning microscopy, and helium ion spray.
Various studies have revealed that spider silk fibers consist of at least two outer lipid layers, namely lipids. Behind it, inside the fibril, there are many so-called fibrils that are arranged straight and tightly arranged side by side (see image). The fibril diameter ranges between 100 and 150, less than the limit that can be measured with ordinary optical microscopes.
Illustration from Scientific report Paper: Schematic representation (not to scale) of the proposed structure of spider silk fibers as found in this work. (A) Side view of the fiber, (B) Cross section of the fiber. An outer non-conductive lipid-rich layer (green) 0.6 to 1 µm thick, and two inner conductive layers of autofluorescent protein: one showing higher affinity for FITC (blue), and the other showing higher affinity for rhodamine B (orange) . The inner protein core consists of crystalline fibers, parallel to the long axis of the fiber, surrounded by amorphous protein regions. Source: Iachina/Brewer, University of Southern Denmark.
“It is not twisted, as one might think, so now we know that there is no need to twist it when trying to make artificial spider silk,” said Irina Iashina.
Iachina and Brewer worked with silk fibers from the golden orb-web spider, Nephila madagascariensis, which produces two different types of silk: one, called MAS (primary ampullary silk fiber), is used to make spider webs, and is also the silk used spider to stick to. Irina Iashina calls it the lifeblood of spiders. It is very strong and its diameter is about 10 micrometers.
The other, called MiS (ampullary microsilk fiber), functions as a development aid. It is more flexible and usually has a diameter of 5 micrometers.
According to binary analysis, MAS silk contains fibrils with a diameter of about 145 nm. Meanwhile for MiS, it is around 116 nm. Each fiber is made up of protein, and several different proteins are involved. This protein is produced by spiders when making their silk fibers.
Understanding how these strong fibers are created is important, but producing the fibers is also a challenge. Therefore, researchers in this field often rely on spiders to produce their silk.
Instead, they can use computational methods, which Irina Iashina is currently working on at the Massachusetts Institute of Technology: “Right now, I’m running computer simulations of how proteins turn into silk. The goal is of course to learn how to produce artificial spider silk, but I am also interested in contributing to a better understanding of the world around us. .”
Reference: “Nanoscopic imaging of primary and secondary ampulla silk from the orb-web spider Nephila Madagascariensis” by Irina Iachina, Jacek Wiotowski, Horst Günter Ruban, Fritz Vollrath, and Jonathan R. Breuer, April 24, 2023, Scientific report.
doi: 10.1038/s41598-023-33839-z
“Helium ion microscopy and spider silk cutting” by Irina Iashina, Jonathan R. Breuer, Horst Günter Ruban, and Jacek Wojtowski, 22 May 2023, Scan is complete.
doi: 10.1155/2023/2936788
2023-09-14 20:55:38
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