Do you remember in the TV series The Amazing Spider-man? The hero, Peter Parker, had to create his own spider silk to help him fight the bad guys? Well I guess he didn’t do his research, because Japanese startup Spiber says it has found a way to produce spider silk synthetically and over the next two year period will ramp up mass production to enable various designs and creations for the material varying from surgical materials, bulletproof vests and auto parts. (No mention of superheros though). Spider silk is a remarkable material: it is as strong as steel, tougher than Kevlar, lighter than carbon fibre and can be stretched 40 percent beyond its original length before breaking.
From a medical perspective, artificial silk could be used to create blood vessels and ligaments, as well as dissolvable sutures. In the auto industry it could lead to bumpers that can absorb a very large amount of energy on the impact thereby improving driver safety.
The reason behind the amazing properties of Spider silk is it is due to a protein named fibroin. Proteins are the catalyst for chemical reactions inside a cell and they help bind cells together into tissues. If you break it down, they are long chains of about 20 different types of amino acids, which can combine into a nearly infinite number of configurations. The complex sequence of amino acids that make up fibroin has proven tough to recreate in a laboratory. A “spider farm” would not produce nearly enough silk for industrial use, so companies around the world are turning to genetic engineering instead. Some companies have modified goats to produce milk containing spider silk; others used silkworms to the same end; and still others are using genetically modified bacteria to achieve the desired outcome.
Spiber’s approach involves genetically modifying bacteria. The company’s process involves decoding the gene responsible for the production of fibroin in spiders and then bioengineering bacteria with recombinant DNA to produce the protein, which they then spin into artificial silk. While interest in artificial silk is high and competition is tough, Spiber says it has the advantage of speed: apparently, it can engineer a new type of silk in as little as 10 days, and has already created 250 prototypes with characteristics to suit specific applications.
Spiber starts the process by tweaking the amino acid sequences and gene arrangements in its computer models to create artificial proteins that try to maximize strength, flexibility and thermal stability in the final product. Then, the company synthesizes a fibroin-producing gene, modifying it so that it will produce that specific molecule. The company adopts its own system of gene synthesis, which can produce large quantities of DNA for the fibroin gene in only a three day period. Microbes are then modified with the fibroin gene to produce the candidate molecule, which is turned into a fine powder and then spun. The bacteria feed on sugar, salt and other micronutrients and can reproduce in just 20 minutes. A single gram of the protein produces about 5.6 miles (9 km) of artificial silk. The artificial protein derived from fibroin has been named QMONOS, from the Japanese word for spider. The substance can be turned into either a fibre, film, gel, sponge, powder, and nano-fibre to suit a number of different needs, depending on the application.
Spibers says it is building a trial manufacturing research plant, aiming to produce 100 kg (220 lb) of QMONOS fibre per month by November 2013. The pilot plant will be ready by 2015 by which time the company aims to produce 10 metric tons (22,000 lb) of silk per year.
I guess Peter Parker would have nothing more to worry about except fighting The Green Goblin then?
[Images via: spiber]