Imagine a skin that is so strong that it is worthy of Superman. If you are thinking that is just an imagination, then wake up, because a Dutch artist and her team of scientists have just created one. The bulletproof skin is made of bio-engineered skin cells reinforced by synthetic spider silk sandwiched between the cells. Even the spider silk is not just any ordinary silk. It was obtained from a genetically engineered spider-goat whose milk contains spider silk. Unbelievable, isn’t it? Keep reading this article to know more about spider-goat, the goat which produces spider silk is used to make bullet-proof skin.

Thinner than hair yet stronger than steel, spider webs are no less than an enigma for scientists. Researchers have tried creating synthetic spider webs, and some have even had success. One of them is genetics engineer Randy Lewis who had successfully created spider-goats, a goat with spider genes.

Spider silk is one of the strongest materials available in nature. The best among them is the dragline silk which is produced by spiders to catch themselves when they fall. This silk is tougher than Kevlar and has the elasticity and lightness of nylon. For a long time, scientists tried finding a way to manufacture it in large scale. One way is to raise spiders, but it isn’t possible as spiders are extremely territorial, and they have cannibalistic tendencies. Also, using natural spider silk to create an object is time-consuming and quite tricky. For instance, it took more than a million golden orb spiders and 70 human workers working for four years to make a single, 11-foot by 4-foot tapestry. The tapestry was completed in 2009. It is now on display in the American Natural History Museum.

When researchers began looking for other ways to produce spider silk, they found success through genetic engineering. In the early 2000s, a Canadian company approached Professor Randy Lewis, then at the University of Wyoming, to find an alternate way to produce spider silk. Lewis, a molecular biologist, successfully created spider-goats, a genetically modified goat containing spider genes. In 2009, the company went out of business, and Lewis has since moved to Utah State University. His creation, the spider goats, began thriving in the university-run farm.

Spider goats are genetically engineered goats whose milk contains spider-silk protein. Professor Randy Lewis created spider-goats by genetically modifying a part of the goat DNA by substituting it with a spider gene.

All creatures on Earth possess their own unique traits and characteristics. This uniqueness comes from the information coded in their DNA. There are four types of bases in the nucleotide of DNA: adenine (A), thymine (T), guanine (G) and cytosine (C). The order in which these bases are arranged determines the genetic code of all living creatures. The same holds true for the code of spider silk and goat’s milk. Even though both are different, in a broad sense, they are written in exactly the same language. With the help of genetic engineering, scientists cut and paste bits of DNA from one species to another. This is how the spider-goat was created.

The genetic modification process begins with a single gene. A silk-spinning gene of the spider is added to the DNA of a goat. This is done while the goat is still an egg in its mother’s womb. At first, the nucleus and chromosomes from the original egg are taken out. Then the chromosomes from the genetically modified cell are put into the egg. As the egg grows, the genes divide and multiply. Thus, as the goat grows up, it’s body produces spider-silk protein. This gene is passed on to the next generation when the goat reproduces.

The spider-goats at Utah State University have adorable names such as “Pudding,” “Sweetie,” and “Freckles.” They are reared for their milk which contains spider-silk protein. After separating the silk protein from the milk, it is turned into powder which is processed and spun into silk fiber.

A major spider-goat farm now exists in the Utah State University headed by the project head Randy Lewis. The goats reared here have adorable names like “Pudding”, “Sweetie,” and “Freckles.” These spider-goats look just like any normal goat. The only difference is that the milk of these goats is filled with spider-silk protein. Spider silk belongs to a class of materials called “biopolymers” which are protein-based materials of biological origin.

Each genetically modified goat at Utah State University produces about an ounce of the spider-silk protein per milking session. The milk is separated, and the product left is refined several times. Then, it is washed, freeze-dried, and turned into powder. This powder can be spun into a fiber. Also, it can be transformed into a coating or adhesive. After separating, the milk is not kept for human consumption. The fiber produced through spider-goat’s milk is only one-half to two-thirds as strong as the spider silk. But, the elasticity is the same as the original spider silk.

The silk produced by the spider-goats has been used to create various objects, but the most innovative one is bullet-proof skin. Even though the skin is not as impregnable as a Type-1 bullet-proof vest, but it can stop a bullet fired at a reduced speed. The genetically modified skin was displayed in 2011-2012 in a museum in the Netherlands.

The silk obtained from spider-goat’s milk has multiple uses. Due to its strength and durability, it can even be used to make bulletproof vests. When Dutch artist and entrepreneur, Jalila Essaïdi, heard about it, she decided to go a step further and create bulletproof skin. For this project, she collaborated with Forensic Genomics Consortium Netherlands and took help from scientists and technicians in America, South Korea, Germany, and the Netherlands. The spider silk was taken from Utah State University, reeled into a thread in South Korea, and then woven in Germany.

Human skin has three layers: epidermis, dermis, and hypodermis. To create bulletproof skin, cells from the dermis and epidermis were taken. Then, at the Leiden University Medical Center in the Netherlands, the synthetic spider silk was sandwiched between the layers of bio-engineered skin cells. The resulting “skin” was then taken to the Netherlands Forensic Institute for ballistic tests. The test revealed that the skin was successfully able to stop bullets fired at a reduced speed. But when bullets were fired from .22 caliber rifle at normal speed, it pierced the skin.

The test concluded that if humans were fitted with this bulletproof skin and shot at, the skin wouldn’t get pierced. However, the internal tissues would be harmed due to the bullet’s impact. So, further research needs to be done before an actual, bullet-proof “super skin” becomes a reality. This bullet-proof skin was displayed at the National Natural History Museum Naturalis in Leiden, the Netherlands in 2011 and 2012.

The creator of bulletproof skin is now using spider-goat silk to create organ scaffolds. Also, in 2015, Utah State University got a $1 million contract with the US Army to produce the silk.

After experimenting with bulletproof skin using synthetic spider silk, Jalila founded the company “Inspidere.” It develops sustainable materials, including synthetic spider silk. The synthetic spider silk is being used to create organ scaffolds. Organ scaffolds, or bioscaffolds, are meant to be implanted in the human body. There are very few materials through which bioscaffolds can be made as most materials are not bio-compatible with the human body. Since spider-silk protein is compatible with the human body, it is combined with cobalt-chrome (CoCr) to shape functioning, synthetic organs.

Just like Jalila, many other researchers, scientists, and artists are trying to create new items using spider silk. Even the US Army is interested in synthetic silk. In 2015, they provided a $1 million contract to Utah State University to produce the silk from spider-goat. The textiles woven for this silk is lighter than Kevlar. Also, unlike nylon, it doesn’t melt, which makes it an attractive material for body armor.

[source: theguardian]