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 Children’s 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 in a speedometer that predicts the type of molecules that will speed up (or not) crystal growth.
The new insights predict the growth enhancing abilities of amino acids, peptide chains and also explain recent reports of very large growth enhancing effects by natural proteins extracted from the shells of abalone.
Their findings add to intrigue of how proteins and other biomolecules rearrange local water to affect many different aspects of biological systems. To now show that this restructuring also influences the growth of crystals adds new momentum to this research area.
In addition to better understanding how organisms can form biominerals with sophisticated shapes, insights to the roles of biology in crystal formation will improve efforts to interpret ancient environments and climate conditions from some fossils. It could also provide new knowledge for inventing materials that can someday approach the same level of complexity in shape and function as Nature has perfected over millions of years with shells, teeth and bones.
Selim Elhadj received his Ph.D. in Chemical Engineering from Virginia Tech in 2001 and Patricia Dove of Blacksburg, professor of geosciences, is a 1980 and 1984 graduate of Virginia Tech who returned to the university after seven years as a professor of geochemistry at the Georgia Institute of Technology. The paper, “Role of Molecular Charge and Hydrophilicity in Regulating the Kinetics of Crystal Growth,” appears in the online issue ahead of publication in PNAS.
Dove and her research group study the interface between minerals, waters, and biomolecules in biomineralization, cementation, chemical weathering, paleoproxy models, metal and biomolecule binding. Located in the Department of Geosciences, they investigate these processes and the underlying reaction mechanisms through direct, nanoscale observations of mineral-water interactions during growth, dissolution, and nucleation with quantitative measurements of kinetics and surface thermodynamic properties. Most projects involve amorphous and crystalline forms of silica and the carbonate polymorphs.
What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering