Madison WI (SPX) Dec 29, 2010
To survive in a tumultuous environment, sea urchins literally eat through stone, using their teeth to carve out nooks where the spiny creatures hide from predators and protect themselves from the crashing surf on the rocky shores and tide pools where they live.
The rock-boring behavior is astonishing, scientists agree, but what is truly remarkable is that, despite constant grinding and scraping on stone, urchin teeth never, ever get dull. The secret of their ever-sharp qualities has puzzled scientists for decades, but now a new report by scientists from the University of Wisconsin-Madison and their colleagues has peeled back the toothy mystery.
Writing in the journal Advanced Functional Materials, a team led by UW-Madison professor of physics Pupa Gilbert describes the self-sharpening mechanism used by the California purple sea urchin to keep a razor-sharp edge on its choppers.
The urchin's self-sharpening trick, notes Gilbert, is something that could be mimicked by humans to make tools that never need honing.
"The sea urchin tooth is complicated in its design. It is one of the very few structures in nature that self-sharpen," says Gilbert, explaining that the sea urchin tooth, which is always growing, is a biomineral mosaic composed of calcite crystals with two forms - plates and fibers - arranged crosswise and cemented together with super-hard calcite nanocement. Between the crystals are layers of organic materials that are not as sturdy as the calcite crystals.
"The organic layers are the weak links in the chain," Gilbert explains. "There are breaking points at predetermined locations built into the teeth. It is a concept similar to perforated paper in the sense that the material breaks at these predetermined weak spots."
The crystalline nature of sea urchin dentition is, on the surface, different from other crystals found in nature. It lacks the obvious facets characteristic of familiar crystals, but at the very deepest levels the properties of crystals are evident in the orderly arrangement of the atoms that make up the biomineral mosaic teeth of the sea urchin.
To delve into the fundamental nature of the crystals that form sea urchin teeth, Gilbert and her colleagues used a variety of techniques from the materials scientist's toolbox. These include microscopy methods that depend on X-rays to illuminate how nanocrystals are arranged in teeth to make the sea urchins capable of grinding rock. Gilbert and her colleagues used these techniques to deduce how the crystals are organized and melded into a tough and durable biomineral.
Knowing the secret of the ever-sharp sea urchin tooth, says Gilbert, could one day have practical applications for human toolmakers. "Now that we know how it works, the knowledge could be used to develop methods to fabricate tools that could actually sharpen themselves with use," notes Gilbert.
"The mechanism used by the urchin is the key. By shaping the object appropriately and using the same strategy the urchin employs, a tool with a self-sharpening edge could, in theory, be created."
Share This Article With Planet Earth
University of Wisconsin-Madison
Space Technology News - Applications and Research
Berkeley Researchers Discover Mobius Symmetry In Metamaterials
Berkeley CA (SPX) Dec 21, 2010
Mobius symmetry, the topological phenomenon that yields a half-twisted strip with two surfaces but only one side, has been a source of fascination since its discovery in 1858 by German mathematician August Mobius. As artist M.C. Escher so vividly demonstrated in his "parade of ants," it is possible to traverse the "inside" and "outside" surfaces of a Mobius strip without crossing over an edge. ... read more
Ever-Sharp Urchin Teeth May Yield Tools That Never Need Honing|
Tablet computers come of age with iPad mania
New Kindle becomes Amazon's all-time best seller
Skype brings video calls to iPhone, iPod, iPad
IBCS Completes Warfighter-Centered Design Exercises
Arianespace Will Orbit Sicral 2 Milcomms Satellites
Codan Receives JITC Certification For 2110 HF Manpack
Northrop Grumman Bids for Marine Corps Common Aviation CnC
Eutelsat's KA-SAT Satellite Lofted Into Orbit
Extra Weight May Have Caused GSLV Problems
ISRO Puts Off GSLV Launch
Arianespace To Launch ESA's First Sentinel Satellite
Launch Of New Russian Navigation Satellite Postponed To Next Year
Galileo's Navigation Control Hub Opens In Fucino
China Launches Seventh Orbiter For Indigenous Global SatNav System
Universal Address And GPS Enhanced Google Maps For iPhones
Cathay makes pay offer to pilots: report
India's first C-130 heads for base in 2011
Facebook chorus prompts Qantas to scrap instruments ban
China, Taiwan agree to more flights for Lunar New Year
Better Control Of Building Blocks For Quantum Computer
S.Korea's Hynix says chip price slump will hit Q4 profit
Making Wafers Faster By Making Features Smaller
TerraSAR-X Image Of The Month: Ice Flow Like Molten Metal
GOES-13 Satellite Captures Powerful Snowmaker Leaving New England
ESA Unveils Latest Map Of World's Land Cover
TanDEM-X Ready For Routine Operations In 2011
'250 billion' plastic fragments in Mediterranean
Long Lasting Chemicals Threaten The Environment And Human Health
Montenegro town's dream: from toxic dump to eco-tourism hub
Firefighters to hose Naples down on New Year's Eve
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement|