Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Signpost for Chemical Snaps

29.04.2011
Copper ions as morphogens for the formation of polymer films by click chemistry

Scientists are envious of nature because of its ability to build up highly complex structures like organs and tissues in an ordered fashion without any problem; it takes a great deal of effort for scientists to produce defined microscale structures.

Pierre Schaaf and a team of scientists from Strasbourg have now imitated a few of nature¡¯s tricks in order to get a polymer film to ¡°grow¡± onto a surface. As the researchers report in the journal Angewandte Chemie, they used morphogens as nature does. These signal molecules show a reaction which way it should go.

The growth of our bones, seashells, or the complicated forms of diatoms, requires the processes involved in biomineralization to occur along precisely controlled tracks. Molecules cannot simply be allowed to react in an uncontrolled fashion as soon as they encounter each other.

In order for a complex organism to develop, every individual cell must know where it is located within a growing organ. Special signal molecules called morphogens inform the cell. They are formed in a specific location and then spread out into the surrounding tissue. This results in concentration gradients, which the cells can use to ¡°orient¡± themselves.

Schaaf and his co-workers chose a similar strategy to form thin films on a substrate. They also used a sort of morphogen to steer the process. The reactants involved were polymers, one containing azide groups (¨CN3) and the other with alkyne groups (¨CC¡ÔCH) as side chains. In the presence of positively charged copper ions (CuI), these groups react with each other to form a carbon- and nitrogen-containing five-membered ring, crosslinking the polymers. This type of reaction is called ¡°click chemistry¡±, because the reaction partners simply snap together.

In a solution containing both click partner and CuI ions, the reaction would immediately proceed at random. This would not result in a thin polymer film. The scientists¡¯ idea was thus to place the CuI ions as a morphogen only on the surface to be coated. Their approach was to place CuII ions in the solution. They then applied an electric voltage to the surface. When CuII ions come into contact with this surface, they take an electron to become CuI. These are thus primarily to be found on the surface. Where there are CuI ions, the click reaction can proceed; the polymers only crosslink into a continuous film on the surface. The magnitude of the applied voltage can be used to control the number of CuI ions and thus the thickness of the film.

Author: Pierre Schaaf, Institut Charles Sadron, Strasbourg (France),
http://www-ics.u-strasbg.fr/spip.php?article284
Title: Electrochemically Triggered Film Formation by Click Chemistry
Angewandte Chemie International Edition 2011, 50, No. 19, 4374¨C4377, Permalink to the article: http://dx.doi.org/10.1002/anie.201007436

Pierre Schaaf | Angewandte Chemie
Further information:
http://pressroom.angewandte.org
http://www-ics.u-strasbg.fr/spip.php?article284
http://dx.doi.org/10.1002/anie.201007436

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>