What is spider silk?

Spider silk is a natural protein fiber that is always sought after for its mechanical properties and is considered to be superior to silkworm silk. Spider silk also known as gossamer is tougher than steel by weight and more durable than Kevlar while exhibiting incredible elasticity and can be stretched about two to five times its original length without being broken.

There are about seven different types of silk extruded by the spiders through their abdominal glands that function as biofactories and secrete silk protein i.e. fibroin. The types of silk are distinguished by the structure of the protein and possess different properties, composition and morphologies.

However, spider silk is difficult to produce in large quantities and hence find less application in the textile industry. This is because it is difficult to domesticate spiders due to their predatory nature and unlike silkworm, the spider web can not be reeled into a single fiber. Also, the spiders produce silk or more precisely webs in order to catch prey, production of egg sacs, carry semen from the abdomen to the male palp and various other functions while silkworm utilises silk for protection against metamorphosis. The strongest silk is dragline silk produced by the Golden Orb spider.

Although silkworm has been used to extract silk for about 5000 years, spider silk is trying to make its way in the textile market and various research is going on to produce large quantities of spider silk. In the late 1990s, the first artificial spider silk was developed by Nexia Biotechnologies, trade name BioSteel. The method involved transferring of spider dragline silk gene into mammary glands of goat and so the spider silk proteins were extracted from the milk of a lactating goat.

After which various techniques have been introduced to produce spider silk. Qmonos, a bio-material derived from spider silk, is the latest innovation in this area. Spiber, a Japan-based company has bought the synthetic spider silk into the market and has succeeded in fibroin protein synthesis without using goat milk. Qmonos, derived from a Japanese word kumonosu which literally means spiderweb. The method used by Spiber obtains protein by the marriage of bioengineered bacteria and recombinant DNA. The protein extracted from these bacteria is in dry powder which is further made into thread by the process of extrusion. Thus, the company aims to produce the spider silk at a large scale as mass production for which it has also collaborated with North Face in 2015 to launch a jacket that could bear harsh environment conditions and called it as Moon Parka. The most prominent feature of the jacket is that its outer shell consists of Qmonos fabric which is entirely biodegradable.