Speaking of alternative energy, this subsance is not one; it is an alternative to steel that is gaining in acceptance and finding niches of practical application.
"UW will begin processing the goat's milk containing the spider silk protein for the production of recombinant spider silk -- BioSteel -- for Nexia. About 5,200 pounds, or about 600 gallons, has been delivered, says Lewis, who has built an international reputation for his spider silk research.
www.uwyo.edu/news/showrelease.asp?id=8959
Spider silk is a fibre secreted by spiders. Spider silk is a remarkably strong material. Its tensile strength is comparable to that of high-grade steel — according to Nature (see reference below), spider silk has a tensile strength of roughly 1.3 GPa, while one source [1] lists a tensile strength for one form of steel at 1.65 GPa. However, spider silk is much less dense than steel; its ratio of tensile strength to density is perhaps 5 times better than steel — as strong as aromatic nylon filaments, such as DuPont's Kevlar.
Artificial spider silk
Spider silk's properties have made it the target of industrial research efforts. It is not generally considered possible to use spiders themselves to produce industrially useful quantities of spider silk, due to the difficulties of managing large quantities of spiders. Unlike silkworms, spiders are aggressive and will eat one another, making it impossible to keep many spiders together. Other efforts have involved extracting the spider silk gene and using other organisms to produce the required amount of spider silk. In 2000, Nexia, a Canadian biotechnology company, was successful in producing spider silk protein in transgenic goats. These goats carried the gene for spider silk protein, and the milk produced by the goats contained significant quantities of the protein. Attempts to spin the protein into a fiber similar to natural spider silk failed, however. The spider's highly sophisticated spinneret is instrumental in organizing the silk proteins into strong domains. Specifically, the spinneret creates a gradient of protein concentration, pH, and pressure, which drive the protein solution through liquid crystalline phase transitions, ultimately generating the required silk structure (which is a mixture of crystalline and amorphous biopolymer regions). Replicating these complex conditions in lab environment has proved difficult. Nexia attempted to press the protein solution through small extrusion holes in order to simulate the behavior of the spinneret, but this was insufficient to properly organize the fibers. Ultimately, Nexia was forced to abandon research on artificial spider silk, despite having successfully created the silk protein in genetically modified organisms.
en.wikipedia.org |
