To almost match spider silk, scientists regenerate silkworm silk
Pound for pound, spider silk is among the strongest known materials. Unfortunately, though, farming spiders for their silk is highly impractical. While some researchers are pursuing synthetic spider silk, scientists at MIT and Tufts University have taken another approach … they've devised a method of using silkworm silk to produce fibers that are almost as stiff as spider silk.
The process involves chemically dissolving silkworm cocoons, but only to a certain point. Their molecular structure is left intact, causing the silk fibers to break down into tiny thread-like structures known as microfibrils. MIT's Prof. Markus Buehler likens the process to tearing down a brick house, but leaving the individual bricks intact.
The solution is subsequently extruded through a small opening, causing these microfibrils to reassemble into a single fiber. Known as regenerated silk fiber (RSF), the resulting material is reportedly twice as stiff as regular silkworm silk.
Along with taking the form of traditional fibers that get woven to form textiles, RSF could also be formed into structures such as meshes, tubes, coils and sheets. Because silk is naturally biocompatible, possible applications for the material could include medical sutures, or scaffolding for the growth of new tissue.
Additionally, however, RSF can be made electrically conductive by coating it with a layer of carbon nanotubes. In that case, it could conceivably find use in smart fabrics, such as anti-bedsore bedsheets that warn caregivers when a patient has been lying in one position for too long.
A paper on the research was published this week in the journal Nature Communications.