Nov. 5, 2013 — The silk of a
spider feared for its venomous bite could be the key to creating new
super-sticky films and wafer-thin electronics and sensors for medical
implants that are highly compatible with the human body.
Ribbon of silk from brown recluse spider. (Credit: University of Oxford)
A team of scientists from Oxford University (UK) and The College of
William and Mary (USA) studied the brown recluse spider [Loxosceles
recluse] which produces super-thin ribbons of silk as opposed to the
round fibres typically spun by spiders. The researchers report in the
journal Advanced Materials how, in a world-first, they were able to reel and examine the unique properties of the brown recluse's silk ribbons.
Whilst the silk ribbons have the outstanding strength and toughness
of standard spider silk their flat structure makes it possible to study
the material's molecular structure in great detail and investigate what
gives it its strength. The team found that the extreme thinness of the
ribbons, which are up to 10 nanometres wide and only a few tens of
nanometers thick, combined with its stiffness and the ability to adapt
to the shapes of surfaces is what gives it its unprecedented adhesive
properties. The team also found that the surface of the silk ribbons is
covered with tiny, dot-like 'bumps' that the research team suspects
further enhance adhesion.
'The enigmatic ribbon structure of these threads provides us with a
window into spider silk in its simplest form,' said Professor Fritz
Vollrath of Oxford University's Department of Zoology, an author of the
study. 'All other silks are round, rope-like aggregates made up of many
nano-scale filaments. This makes it virtually impossible to study in
great detail the molecular structure of the silk itself, and the
fundamentals for its great toughness.'
Professor Hannes Schniepp of The College of William and Mary, lead
author of the report, said: 'We were able to modify an atomic force
microscope to measure the rigidity of a single recluse fibre and
discovered that this ribbon -- only a few molecules thick -- not only
displays the great properties of other silks but allows us to probe its
structure in unprecedented detail.'
This discovery is expected to have implications for the development
of new super-sticky cling films and also for the manufacture of
thin-film electronic devices, which might even be implanted as sensors
in the human body -- where silks are highly valued for their outstanding
combination of great mechanical strength and excellent biological