Restoring Calcite With Engineering And Evolution

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Though evolution and engineering are two completely different sectors, the two are often seen teaming up with each other. Some of the most important results of this amazing association are Velcro that replicate burrs to large extent, adhesives that look much inspired from gecko’s feet, and medical tapes that are more like spider silk. Moving ahead, now geologic calcite is being restored for replication of their creation process from mollusks. An amazing substance, calcite is known for bearing twice the strength of rock. A new term called ‘Biomimetrics’ has been coined for the processes and technologies that are developed for mimicking natural mechanisms.

For calcite, the biomimetrics is done by adding glycine and aspartic acid with sample single-crystal calcite. A UK/US based university and an industry research team brought up several groups of single-crystal calcite in glycine or aspartic acid solutions. The quantity of amino acid in the crystal was kept in direction proportion with concentration of the solution it was developed in. Because of its abundance, calcite can easily be used for a number of applications.

It is true that hardened calcite is not as strong as other building construction materials, it still holds a large scope in upcoming times. This is not the end of the story, as per Shefford Baker, the Associate professor of Department of Materials Science and Engineering at Cornell, “This certainly opens up the door for us to think about how hard calcite could be made…Now that we-re starting to understand the control mechanisms the question is, could we make a system in which we go further than this?”

“A breakthrough to be able to have controlled and very well quantified amounts of amino acids within single crystals.” Is what Lara Estroff, an associate professor of material science and engineering likes to call it.

Structural biominerals are inorganic compounds that have some of the most noteworthy mechanical properties. However, scientists were yet unable to understand the structure-property associations of the simplest building unit – mineral single crystals that have embedded macromolecules. With the help of model biomineral created from single calcite crystals with glycine/aspartic acid, the researchers were able to understand the origin of higher level hardness of biogenic calcite. They observed and analyzed the lattice distortions of these model crystals through X-ray diffraction as well as molecular dynamics simulations and with the help of solid-state nuclear magnetic resonance. These showed that amino acids are fused as specific molecules in the substance. The team also demonstrated that nanoidentation hardness enhances with the content of amino acid which reaches close to the level of their natural counterparts. A dislocation pinning model explains that the increased hardness can be determined with the force needed for cutting covalent bonds within the molecule.

The research for this purpose is being led by a number of groups who have come together from all over the globe. Most important roles were played by teams from University of York, Cornell, Cambridge, Sheffield, Diamond Light Source (U.K.) and Technion.