| Nexia Biotechnologies Inc. and the U.S. Army Soldier Biological Chemical Command (SBCCOM) have reported they have made the world’s first spider silk fibres from man-made materials with properties similar to natural spider silk. Spider silk has long been admired by material scientists for its unique combination of high performance properties including toughness, strength, lightness and biodegradability. Nexia is developing recombinant spider silk, trade named BioSteel®, for applications in the medical, military and industrial performance fibre markets. With spiders silk long being viewed as the holy grail of materials science, this recent development opens the door for a raft of commercial applications such as medical sutures, biodegradable fishing lines, soft body armour and unique material composites. From here, Nexia will look to produce large quantities of Biosteel using its proprietary transgenic goat technology as well as optimising spinning processes so that they can produce silks with tailored properties. The findings were recently published in Science (Lazaris et al., volume 295), and outline the production of a number of different dragline spider silk proteins via cell culture techniques using silk genes derived from two different species of orb-weaving spiders. These two silks are amongst the strongest that have been reported. Water insoluble silk fibres were produced from monomer silk proteins in aqueous solution. Mechanical testing of the man-made silks showed them to have similar toughness and modulus to the natural fibres, but a lower strength. The Biosteel fibres were also found to have a uniform diameter, good water stability and orientation. The work reported in this paper is the culmination of a joint research and development project between Nexia and the Natick Soldier Center, commenced in May 1999. The Natick Soldier Center is well known for its work in developing high performance fibres systems for military applications. The actual method of silk production involves producing monomers and spinning fibres in an aqueous environment, mimicking the biological method used that has evolved with spiders over the last 400 million years. The water based technique has the advantage that it is much more environmentally friendly compared to conventional methods which use solvents as well as the fact that the silk itself is also eco-friendly. The ability to synthesise spiders silk in this way was also a major step forward as previously scientists had been unable to spin silk with appreciable mechanical properties. Dragline silk is the component of a spiders web that radiates from the centre of the web. Its strength and toughness are unparalleled by any man-made fibre. It is in fact three times tougher then aramid fibre and has a strength five times greater then steel on a per weight basis. It is made by using only amino acids and consists of proteins with multiple repetitive sequence blocks that are responsible for its mechanical properties. Strength that can stop a bee travelling at 20mph without breaking. Nexia holds exclusive worldwide patents covering aspects such as spiders silk genes and proteins, and their transgenic goat technology used to produce commercial quantities of the silk precursors. Nexia are currently involved in a project to increase the numbers of goats capable of producing Biosteel milk, with females expected to be producing the special milk by the second quarter of 2002, paving the way for process optimisation and further product development and commercialisation. | 
