Spider silk glue inspires next-generation technology

July 22, 2011
The inset in the upper right corner of this photo of a typical orb web is an enlarged image of gluey spiral thread, which is key in spider prey-capture.

(PhysOrg.com) -- Water affects orb spider web glue differently than cobweb glue. Orb web glue reacts to humidity, but cobweb glue resists it. These findings by a University of Akron research team inspire the development of new materials according to how they respond to stimuli.

This newly released research by Vasav Sahni, a UA polymer science graduate student; Todd Blackledge, the Leuchtag Endowed Chair and associate professor of biology and integrated bioscience; and Ali Dhinojwala, UA Department of Polymer Science chair and H. A. Morton Professor of Polymer Science, is published in the July 21, 2011, issue of Scientific Reports.

Humidity triggers adaptability

The research shows that the sticky that coats the silk threads orb-weaving spiders spin has a different structure, property makeup and response to humidity than glues produced by their evolutionary descendants, cobweb-weaving spiders. The cobweb spider's gumfoot glue acts as a viscoelastic liquid that is resistant to changes in humidity, consequently maintaining constant elasticity and adhesion.

Orb weavers, on the other hand, produce glue that acts like a viscoelastic solid. Highly humidity-sensitive, this glue expands in magnitude and demonstrates a monotonous increase in elasticity under increased humidity. The glue also displays a decrease in surface adhesion that results in optimal adhesion at intermediate humidity.

"We suggest that observed differences are due to different 'tackifiers' used in these systems," says Sahni. "These results will inspire future efforts in fabricating stimuli-resistant and stimuli-sensitive materials."

Evolutionary changes advance science

Behaviors of natural biomaterials, such as spider glue responses to humidity, provide templates for developing and devices that change dimension, property makeup and function in response to external stimuli, according to Vasav. He adds that provide powerful tools to advance biomimetic research toward understanding key elements that control biomaterials' environmental responsiveness or resistance to stimuli.

The researchers probed individual glue droplets to reach their findings. They explain in their paper that "both orb web and cobweb spiders depend on viscid glue droplets for their silk to adhere to insect prey. Both types of spiders use the same sets of glands to produce the adhesive." However, similarities between the two, for the most part, end there.

The opposite reactions of the two bioadhesives to humidity are as dramatic as the complexity of processes contributing to these phenomena, the scientists explain in their research. Consequently, the researchers designed a polymer model of the glue droplet, dissolved in water, to simplify and better understand the underlying mechanisms that cause the orb web spiders' silk adhesive to react to humidity.

Reactions of spider glue, pine cones, bird feathers, and several other natural materials to different stimuli provide scientists inspiration for developing next-generation materials based on biomimetic research, or research that mimics nature.

Explore further: Sticky gecko feet: The role of temperature and humidity

More information: See "Changes in the Adhesion Properties of Spider Aggregate Glue During the Evolution of Cobwebs."

Related Stories

Sticky gecko feet: The role of temperature and humidity

May 14, 2008

A team of five University of Akron researchers has published the paper, “Sticky gecko feet: the role of temperature and humidity” in PLoS ONE, an open-access, online journal for peer-reviewed scientific and medical research.

Spider web glue spins society toward new biobased adhesives

October 21, 2009

With would-be goblins and ghosts set to drape those huge fake spider webs over doorways and trees for Halloween, scientists in Wyoming are reporting on a long-standing mystery about real spider webs: It is the secret of spider ...

Scientists untangle spider web stickiness

December 3, 2010

Ali Dhinojwala and Vasav Sahni consider themselves materials scientists, not biologists. They study surfaces, friction and adhesion. Nevertheless, they have discovered that understanding how nature makes things stick sometimes ...

Scientists crack the spiders' web code

May 31, 2011

(PhysOrg.com) -- Decorative white silk crosses are an ingenious tactic used by orb-weaving spiders to protect their webs from damage, a new study from the University of Melbourne has revealed.

Recommended for you

Organic semiconductors get weird at the edge

October 6, 2015

As the push for tinier and faster electronics continues, a new finding by scientists at the University of British Columbia (UBC) and Monash University could help inform the design of the next generation of cheaper, more efficient ...

New polymer creates safer fuels

October 1, 2015

Before embarking on a transcontinental journey, jet airplanes fill up with tens of thousands of gallons of fuel. In the event of a crash, such large quantities of fuel increase the severity of an explosion upon impact. Researchers ...

Researchers print inside gels to create unique shapes

September 30, 2015

(Phys.org)—A team of researchers at the University of Florida has taken the technique of printing objects inside of a gel a step further by using a highly shear-rate sensitive gel. In their paper published in the journal ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.