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Tufts University bioengineers have
discovered how spiders and silkworms are able to spin
webs and cocoons made of incredibly strong fibers. The
answer lies in how they control the silk protein
solubility and structural organization in their
glands.
"This finding
could lead to the development of processing methods
resulting in new high-strength and high-performance
materials used for biomedical applications, and
protective apparel for military and police forces,''
said David Kaplan, professor and chair of biomedical
engineering, and director of Tufts' Bioengineering
Centre.
"We identified
key aspects of the process that should provide a
roadmap for others to optimize artificial spinning of
silks as well as in improved production of silks in
genetically engineered host systems such as bacteria
and transgenic animals,'' said Kaplan, also a
professor of chemical and biological engineering. He
and former postdoctoral fellow Hyoung-Joon Jin
published their findings in the journal Nature.
Silk is the
strongest natural fiber known, but its strength
has yet to be replicated in a laboratory. One reason
may be the previous lack of understanding of how
spiders and silkworm process the silk. The Tufts team
has identified the way that spiders and silkworms
control the solubility, concentration and structure of
the proteins in their glands that spin the silk.
According to
Kaplan, silk proteins are organized into
pseudo-micelle or soap-like structures that form
globular and gel states during processing in the
glands. This semi-stable state, with sufficiently
entrapped water and liquid crystalline structures,
prevents the proteins from crystallizing too early,
until the spinning process. |