Blacksburg, Va., Dec. 4, 2006 -- From gemstones to transistors, crystals are everywhere in our daily lives. Crystals also make up the mineralized skeletons of all organisms, including seashells and our own teeth and bones. Perhaps the most widely used biominerals are found in the calcium carbonate family. Understanding how this mineral forms is of particular interest because of its widespread occurrence over geologic history and its close relation to the calcium phosphate found in the bones and teeth of all mammals.

One ongoing question is how organisms form these mineralized structures, or biominerals, at a controlled rate, sometimes very rapidly until attaining the prescribed size. For reasons not well understood, this process can also go astray, leading to underdevelopment or unwanted growth such as kidney stones. The speed of mineral formation in both normal and pathological development can sometimes be surprisingly fast. For example, phytoplankton, whose occurrence is so extensive that they are believed to have important controls on earth climate, form fully developed and exquisitely shaped skeletons within a few hours.

In the December 4-8, 2006, online Early Edition of the Proceedings of the National Academy of Sciences, Virginia Tech Postdoctoral Scientist Selim Elhadj and Professor Patricia Dove report that the chemistry of organic molecules control the rate of crystal growth. In collaboration with James De Yoreo at Lawrence Livermore National Laboratory and John Hoyer of the Childrens Hospital of Philadelphia, they learned that nano-quantities of biomolecules frequently found in the tissues of organisms where biominerals develop can cause calcite crystals to grow faster. More importantly, they determined that the speed of growth can be tuned by varying the charge and water-structuring ability of the biomolecules. By finding a relationship between the control of electrical charge and hydrophilicity, respectively, the findings result
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Contact: Susan Trulove
STrulove@vt.edu
540-231-5646
Virginia Tech
4-Dec-2006