Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Surface Can Find Different Twists on a Molecular Theme

02.10.2003


The copper-colored images in the above figure are x-ray pole figures of copper-oxide (CuO) films that researchers at the University of Missouri-Rolla have deposited onto a gold surface. The grey background is a scanning electron microscope image of one of the CuO films. The researchers created the pole figures—which represent data, not images of molecules—using an advanced measuring instrument called an x-ray diffractometer. Scientists use x-ray pole figures to determine the atomic structure and orientation of crystalline materials. As with a person’s right and left hands, the CuO films (and their pole figures) cannot be superimposed on one another. This concept is called chirality, and is a characteristic of many biologically-important molecules. The CuO films have been shown to distinguish between the left- and right-handed versions of molecules, an important trait researchers can use to create new chemical sensors and catalysts.
Credit: Jay Switzer and Eric Bohannan, University of Missouri-Rolla; National Science Foundation


Principal investigator Jay Switzer of the University of Missouri-Rolla (second from left) with collaborators Eric Bohannan (on right) and Shuji Nakanishi (far right) and student Hiten Kothari (far left). The team is standing in front of the x-ray diffractometer equipment purchased with the NSF award.
Credit: Photo courtesy of Bob Phelan/Photomasters

Researchers have created a new process to produce materials that can sift through similar, molecular brethren and latch onto chemicals that differ from each other in only their mirrored images.

If it proves effective in large-scale experiments, the stable, relatively simple catalyst could impact the $100 billion pharmaceutical industry by helping sort biologically potent chemicals from related, yet less useful or even toxic, compatriots.

Jay Switzer and colleagues at the University of Missouri at Rolla announce their discovery in the October 2, 2003, issue of the journal Nature. The research was funded primarily by the Division of Chemistry and the Division of Material Research at the National Science Foundation (NSF), the independent federal agency that supports research and education across all fields of science and engineering.

The new material, a thin film of copper oxide on a layer of gold, has an inherent "handedness." Just as human hands come in a left and right-handed variety, so do some molecules. "It’s just like the difference between shaking hands between a right- or left-handed person," said NSF program officer and chemistry expert Mike Clarke. "The handclasp is much easier if it’s right-right or left-left, and harder if it’s right-left or left-right." The handedness property, called "chirality," is fundamentally related to how the molecule reacts with other substances.

Approximately one-third of all drugs are chiral, says Switzer, and the top-10 list for these products includes such familiar brand names as Lipitor, Zocor, Paxil, Zoloft, and Nexium-all of which yield sales of over $1 billion a year.

Currently, most industries make bulk quantities of chiral molecules by mixing handed molecules and other chemicals in a solution. "The ’hands’ gather atoms, assembling chiral, molecular ’gloves,’" said chemist Katherine Covert, one of the NSF program officers who oversees funding of Switzer’s research.

"But, separating the useful ’gloves’ from the chemicals that assembled them can be a difficult process," she added.

Switzer and his colleagues have created a material that serves as a bank of "hands," a solid structure on which reactions can occur and from which researchers can more easily separate desirable chemicals.

To do this, the group used tartrate, a common substance that often crystallizes on the bottom of wine corks. In 1848, when Louis Pasteur was 26, he used tweezers to separate right- and left-handed forms of sodium ammonium tartrate under a microscope.

"The crystals have a different shape," said Switzer. "When Pasteur dissolved the crystals in water, one set rotated polarized light to the right, and the other form rotated it to the left. This experiment is usually cited as the discovery of chirality in molecules," he added.

Tartrate was therefore the first molecule ever isolated in right handed and left-handed forms, which chemists now refer to as the R (from the Latin rectus) and S (from the Latin sinister) forms.

"We’ve made a material that is entirely chiral, not just the surface," said Switzer. "In earlier experiments, you would modify a surface with a chiral modifying agent, and if the agent washes off, the surface is no longer effective. In our new research, the film itself is chiral-the effectiveness remains even after many chemical reactions," he added.

To create the new catalyst, the researchers immersed gold in a liquid containing copper and the handed chemical tartrate, while applying an electric current to the system. The electricity caused copper oxide to bond to the gold. The technique is much like the simple electroplating used to produce the shiny chrome on automobiles.

The gold atoms were highly organized in a crystal structure, but the structure was symmetrical and did not affect the final handedness of the material. Instead, the chiral structure of the tartrate molecules caused the copper oxide to bind to the gold layer-by-layer and in an oriented fashion, creating a handed film.

Once the copper oxide film forms, the copper and oxygen atoms are tightly attached and exist as a single material. In initial tests, the researchers have shown the material can differentiate between chiral tartrate without breaking down or being permanently altered. Pending tests will apply the same technique to amino acids and sugars, such as glucose.

Now, Switzer and his colleagues hope to use their process to create new catalysts and separate different chemicals. In addition to numerous industry uses, the researchers hope similar catalysts may eventually be modified to create sensors for security applications.

Switzer is supported by NSF through both the Division of Chemistry and the Division of Materials Research.

Trademarks for prescription drug names that appear in this press release - Lipitor, Zocor, Paxil, Zoloft, and Nexium - are the trademarks of their respective owners.

Josh Chamot | NSF
Further information:
http://www.nsf.gov
http://www.nsf.gov/od/lpa

More articles from Materials Sciences:

nachricht Move over, Superman! NIST method sees through concrete to detect early-stage corrosion
27.04.2017 | National Institute of Standards and Technology (NIST)

nachricht Control of molecular motion by metal-plated 3-D printed plastic pieces
27.04.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Materials 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

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

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>