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Spider silk: Incredible natural filaments and its future

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Swaraz Mollick,  3rd year student, Khulna University of Engineering & Technology

Joy Sarkar, Assistant Professor, Khulna University of Engineering & Technology

In the Beginning

screenshot-12As we know that The ‘Silk’ is the one and only continuous filament that found in nature. In general, it is known to most of the people that it is found form the silk worms and this worms produces the worlds natural finest and lustrous strands. Fortunately silk worms are not the one and only source for silk. There is other source in the nature from which the silk can be extracted. All the problems are that, there is no proper way through which the silk can be collected from those sources so easily.

The silk is protein based animal fiber which is normally collected from the silk cocoons after some special process and treatments. Though this silk and the processes are founded a long ago, from the ancient time. But at the same times the spider from a special species are also capable of producing the silk. Basically most of the spiders are capable to do that, but specially the Golden orb type female spiders are able to produce special golden silk and also the humble spiders can produce stronger silk filaments.As we know that The ‘Silk’ is the one and only continuous filament that found in nature. In general, it is known to most of the people that it is found form the silk worms and this worms produces the worlds natural finest and lustrous strands. Fortunately silk worms are not the one and only source for silk. There is other source in the nature from which the silk can be extracted. All the problems are that, there is no proper way through which the silk can be collected from those sources so easily.

Significant properties that make it special

For using in textile uses, the fibers or filaments have to maintain some properties such as strength, elasticity, luster or resiliency etc. In case of worm silk, the properties are quite satisfactory and it is familiar for its luster specially.

But, considering the properties, the spider silk could be of a great example. This silk provides a better elasticity than other natural fibers. It can be stretched up to 40% of its normal length. And considering the tensile strength, the spider silk isincredibly stronger than the steel and tougher than the Kevlar. It is one of the sturdiest materials found in the nature.

Comparison of the Properties of Natural Spider Silk, Kevlar® and Steelscreenshot-13

Research and recent Developments

As we know that, the Spider silk is extracted from spiders, more precisely special types of spiders. So it is not so easy to collect and modified the natural spider silk. But, on the contrary it has some great properties to produce textiles. In the recent time, researchers are normally working on how to replicate the spider silk as it is the toughest as well as the elastic one. So, researchers are trying to find a way and to apply this material in various areas like medicine and industries.

Recently, a researcher’s team at University of Cambridge is trying to mimics the spider silk and had a great result indeed. Though, 100% replication is not possible very easily, according to them. But they created material that has approximately the similar strength, stretchiness and energy-absorbing capacity of the spider silk. The most impressive properties of the material are that it is basically 98% water which is made from Hydrogel with 2% silicon and cellulose.

This silk can absorb so much energy. When birds or flies hit their web, it is necessary to absorb the shock; otherwise the web could be broken. So this capacity of absorption is necessary. And for this type of features, the silk can be used in protective tools and coverings like shrapnel resistant or protective military clothing.

screenshot-14But the researchers are not successful yet as the silk extract from spiders are mainly liquid protein which is produced in special gland of the abdomen of spider and then it applied mechanical force to rearrange the molecular structure of protein to turn it into solid silk.

Will it be luxurious?

Though natural silk is not so much available for producing clothing or other textiles, the silk demands a high value. A rare piece of textile fabric is made somehow by the silk. But for weaving the fabric, silk from about one million wild spiders are used and it takes almost four years for collecting the silk and weaving the fabric!

About 70 spider handlers are involved in collecting Golden orb spiders while 12 people were engaged in weaving the fabric. This people extracted about 80 feet of the silk form every arachnids and the lustrous golden colored fabric is the largest piece of textile weaved by the natural silk.

The co-led of this project was Simon peers, a textile expert. He uses the spider silk extracting machine designed by Father Jacob Paul Camboué, who worked on spiders in Madagascar. According to the team, it is found that about fourteen thousands spiders can produce an ounce of silk and the fabric is approximately 2.26 pounds. This numbers say how precious theywill be if they can be produced industrially.

So, what are the problems?

Due to its extremely incredible properties like high tensile strength, luster and elasticity, it holds a great promise for industrial and commercial applications. Unfortunately the problem is mainly that there was no better way to extract the silk from the spiders. Besides, the spiders are normally cannibalistic; they cannot be raised in concentrated colonies like the silk worm. Because, spiders have habits of chomping off each other’s heads when raised together.

Again, if we have to collect the silk from the spiders which naturally produce silk, we have to wait for the perfect time. For example, the Golden orb spiders produce the golden silk during rainy season, so the spiders have to be collected between June to October.

But there are problems also. The spiders can bite, and some of the spiders are poisonous. So, people engaged in the collection of spider have to be conscious always. On the other hand, the silk cannot be extracted so much at a time. It takes nearly one week to regenerate the silk for the spider. As a result the fabric produces by Simon takes four years to complete.

 Future: What researchers are thinking?

screenshot-15But the researchers are getting to this thing closer day by day. When the actual gene sequence of those spiders can be decoded and the researcher can be able to insert them in bacteria, then it can be a way produces this valuable silk. Again, if it can be available to replicate the process by which the spiders solidify the liquid protein, we can create the artificial spider silk in the laboratory.Obviously it is not a common practice to produce fabrics for four years and not for the researchers to study the properties. Several groups of researchers are now trying to produce the artificial silk in the laboratory. The advancement in the biotechnology now drives the researchers to insert the genes of spider to micro-organisms like bacteria, yeast, tobacco plants, even goats! But, the results are moderately successful.

A Japanese biomaterial company, Spiber; which engages in research on synthetic spider silk and other protein-based materials, already produces a spider-parka with the Goldwin Company. But the cost of it is a big deal. Because this parka costs almost 80,000 yen, that means $768 nearly.

Researchers are optimistic that soon they will find a way to produce it. On the other hand, the industries said that they are not thinking about the potential of the silk so early, rather it will take almost a decades for mass production of spider silk. And if that will happen, a new era in textile for spider silk will be opened.

References:

[1]www.wired.com/2009/09/spider-silk/

[2] www.smithsonianmag.com/innovation/new-artificial-spider-silk-stronger-steel-and-98-percent-water-180964176/

[3]www.kraiglabs.com/spider-silk/ qz.com/708298/synthetic-spider-silk-could-be-the-biggest-technological-advance-in-clothing-since-nylon/

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