Science and Technology:Learning it from Mother Nature.

Sea urchins 'could lead to knives that never need sharpening'

Agencies.

Posted: Sun Dec 26 2010, 17:40 hrs 
London:  
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Believe it or not, sea urchin's teeth could hold the key to everlasting sharp tools.


Scientists have found that sea urchins dig themselves hiding holes in the limestone of ocean floor using teeth which do not go blunt, a key finding which they claim could be used in technology to help to create everlasting bladed tools.



Analysing the teeth of California purple sea urchin, an international team has found that a complex structure of layered calcite crystals held together by super-hard natural cement, 'The Daily Telegraph' reported.



Between the crystals are layers of weaker organic material. As each hard layer becomes blunt it breaks off, exposing a fresh crystalline surface beneath. In this way, the sea urchin's teeth stay sharp.



Prof Pupa Gilbert from the University of Wisconsin- Madison, who led the team, was quoted as saying, "The organic layers are the weak links in the chain. There are breaking points at predetermined locations built into the teeth. It's a concept similar to perforated paper in the sense that material breaks at these predetermined weak spots." 



The crystals come in two forms, plates and fibres arranged crosswise in a tough "biomineral" mosaic.



Prof Gilbert added: "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.



"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."



The findings have been published in the 'Advanced Functional Material' journal.

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