Revealing the Secrets of the Web

“Supercontraction is an amazing thing. When spider silk gets wet, the fibres shorten by half and double in diameter,” says NSERC researcher Dr. Carl Michal who with Philip Eles, an NSERC scholar, has studied the mechanism behind supercontraction. Their work is the clearest evidence yet of how it works at the molecular level.

Dr. Carl Michal, the University of British Columbia physicist, and his research team studied the dragline silk of the golden orb-weaver spider. This large spider – its body is three to four centimeters – is a silk-generating factory, spinning up to 150 meters of silk until it runs dry – more than enough for Dr. Michal to conduct solid-state nuclear magnetic resonance (NMR) experiments.

What the research shows is that as spider silk absorbs water, parts of the silk undergo a large-scale molecular transition, its molecules go from a rigid state to a mobile liquid-like state. The NMR experiments looked at the different frequencies of molecular motion during silk supercontraction. “The thing we didn’t expect to see is that we can control the number of amino acids that contribute to the supercontraction,” Dr. Michal explains.

Dr. Michal says that understanding the process of supercontraction is the first step. His research takes us a step closer to the goal of controlling it and one day creating artificial silk fibres.

It’s an idea that has tantalized scientists for years.

A spider’s dragline silk, which spiders spin as they fall, is five-times stronger than steel, stretches twice as far before breaking than nylon, and is biodegradable. Potential applications include improved sutures and artificial tendons, biodegradable fishing lines, stronger parachute cords, and lightweight bulletproof vests.

Contact:

Dr. Carl Michal
Tel.: (604) 822-2432
E-mail: michal@physics.ubc.ca
Web site: http://www.physics.ubc.ca/~michal/