Five times tougher and 16 times more extensible than a human tendon, the leathery, yet amazingly stretchy collagen threads produced by marine mussels might someday suggest strategies for developing better artificial skin and other biomimetic materials, say University of Delaware researchers whose work appears in the Sept. 19 issue of Science.
Described as containing "the first known protein [with] both collagenous and elastin-like domains," byssal threads help mussels latch onto rocks, oil rigs, super-tankers and docks, the UD researchers say. Not surprisingly, mussels "create a major fouling problem on economically important surfaces exposed to the sea," says J. Herbert Waite, professor of marine biochemistry in UD's College of Marine Studies.
Byssal threads feature "a stiff tether" at one end and a "shock absorber" on the end protruding from the mussel foot, explains graduate student Kathryn J. Coyne, lead author of the Science article, along with postdoctoral research associate Xiao-Xia Qin and Waite. This gradual transition, from one material to another, gives byssal threads a surprising mix of properties.
"If a byssal thread were simply a stiff stick attached to an elastic tube, it wouldn't have an outside chance of surviving these relentless tidal beatings," Waite notes. "In fact, the collagen in byssal threads goes from being a stiff material, to something that's very stretchy--without any sudden transitions." It's not yet feasible to manufacture materials featuring such gradual transitions, Waite says. But, he adds, "It's fun to dream about versatile new materials for a whole host of products--from steel-belted radials to shoes, which must be soft and flexible, yet tough enough to pound the pavement." Waite emphasizes that his current work primarily provides fundamental insights into the molecular construction of byssal threads.
In the future, however, a better understanding of byssal threads might help scientists design biomaterials that
Contact: Ginger Pinholster
University of Delaware