Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oh the Shark Has Pretty Teeth Dear…

24.01.2014
Atomic resolution imaging of fluorine in shark tooth enamel

Shark teeth are supposedly the healthiest of all animals because of their particularly hard enamel. Japanese researchers have now been able to use a special electron microscopy technique to image the structure of shark enamel.



In the journal Angewandte Chemie, they report on an unusually strong bond between fluorine atoms and calcium atoms, which may be responsible for the unusual hardness and cavity resistance of shark teeth.

Biominerals play an important role for all life forms. Our own bones and teeth consist of a composite material made from biomolecules and inorganic substances. Shark tooth enamel is mainly fluorapatite (Ca5[F(PO4)3]), a mineral with a hexagonal crystal structure that contains calcium, fluorine, and phosphate. But what is it that makes the shark’s tooth enamel so particularly strong? So far, all we have determined is that it has a high density of fluorapatite crystals and a low content of organic matrix.

Determining the exact structures of biominerals turns out to be distinctly difficult. In the best cases, experiments using transmission electron microscopy have been able to deliver information on the nanometer scale. Advances like aberration correction have improved the resolution of TEM, but the signals are weak and the structures extremely complex.

In addition, the electron beam damages biominerals. A team led by Yuichi Ikuhara has now been able to examine the enamel of shark teeth by TEM and scanning TEM (STEM) with minimum interference. To achieve this, the researchers from Tohoku University, the University of Tokyo, the Graduate School of Tokyo Medical and Dental University, and the Fine Ceramics Center used an aberration-corrected electron microscopy technique that gets by with a very low dose. This method works by using a smaller condenser aperture and dispersing the electron beam over a wider area of the sample than usual.

The scientists were thus able to spatially resolve each individual atom columns inside the complex fluorapatite structure. They found that shark tooth enamel consists of bundles of monocrystalline nanorods of fluorapatite with a diameter of about 50 nm. The hexagonal shape of the crystal could also be confirmed. Every hexagon consists of calcium, phosphorus, and oxygen atoms with a fluorine atom at the center. By using ab initio calculations, the researchers were able to determine that the fluorine atoms are bound to the surrounding calcium atoms with covalent–ionic mixed bonds, not ionic bonds alone as expected. This seems to be the main reason for the special cavity resistance of shark teeth.

About the Author
Dr. Yuichi Ikuhara is a Professor at Tohoku University and the University of Tokyo with appointments in materials science. His main specialty is the application of state-of-the-art transmission electron microscopy to solve fundamental issues in materials science. He is also Director of the Research Hub for Advanced Nano Characterization and Nanotechnology Platform at the University of Tokyo, and is the recipient of the Commendation for Science and Technology by MEXT of Japan and the Humboldt Research Award.

Author: Yuichi Ikuhara, Tohoku University (Japan), http://www.wpi-aimr.tohoku.ac.jp/en/research/researcher/y-ikuhara.html

Title: Fluorine in Shark Teeth: Its Direct Atomic-Resolution Imaging and Strengthening Functio

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201307689

Yuichi Ikuhara | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>