Kraig Biocraft Laboratories Inc., Lansing, Mich., developer of spider silk technologies utilizing customized genetic engineering sequences, has created a new variety of recombinant spider silk that it reports has increased strength compared to that of previously developed varieties.
Dubbed "Big Red" because its color has a slight red cast — and under ultraviolet light it exhibits a bright red glow — two varieties of the new composite fiber are being spun by transgenic silkworms that feature two different customized spider silk genetic engineering sequences. It is a follow-up to the company's hybrid Monster Silk™ (see Quality Fabric Of The Month: " Spider Silk: Potential Unleashed," TextileWorld.com, January/February 2012), which is on track to be in commercial production in the first half of 2013, according to Kim Thompson, CEO, Kraig Biocraft.
"This new type of fiber was designed to be a combination of spider silk proteins, silkworm silk proteins and protein from an unrelated species," Thompson said. "From a genetic perspective, what significantly differentiates this material from our Monster Silk™ is the unique spider silk genetic sequence that we used, which we designed to increase strength to weight ratios. Another important difference is the incorporation of a unique protein, which gives the new fiber its designation as 'red.'"
Big Red is stronger than Monster Silk, but it is not as elastic, and Thompson sees the new fiber's applications particularly in certain technical textiles that require added strength but in which elasticity would not be desirable. "Flexibility is a good property for some applications but not others," he said, mentioning that he also wants to weave some structures that contain both fibers. "It will be interesting to see what the test weaves look like when we combine Monster Silk with Big Red," he added.
The company is preparing to conduct mechanical testing of the two Big Red varieties to prove the laboratory's observations of increased tensile strength and decreased elongation as well as the differing mechanical properties expressed in each variety owing to the differences in their genetic sequences.
