Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chemists develop new "light switch" chloride binder

31.08.2010
Chemists at Indiana University Bloomington have designed a molecule that binds chloride ions -- but can be conveniently compelled to release the ions in the presence of ultraviolet light.

Reporting in the Journal of the American Chemical Society today (online), IU Bloomington chemist Amar Flood and Ph.D. student Yuran Hua explain how they designed the molecule, how it works and, just as importantly, how they know it works.

"One of the things we like most about this system is that the mechanism is predictable -- and it functions in the way we propose," said Flood, who led the project.

Chloride is a relatively common element on Earth, ubiquitous in seawater and in the bodies of living organisms.

"We have two main goals with this research," Flood said. "The first is to design an effective and flexible system for the removal of toxic, negatively charged ions from the environment or industrial waste. The second goal is to develop scientific and even medical applications. If a molecule similar to ours could be made water soluble and non-toxic, it could, say, benefit people with cystic fibrosis, who have a problem with chloride ions accumulating outside of certain cells."

Many organic molecules exist that can bind positively charged ions, or cations, and this has much to do with the fact that it is easy to synthesize organic molecules with negatively charged parts. Synthesizing organic molecules that bind negatively charged ions, or anions, like chloride, presents special challenges.

The binding molecule or "foldamer" Flood and Hua designed is both a folding molecule and a (small) polymer, meaning the foldamer's constituent parts can be synthesized with relative ease. Under visible light of 436 nanometers (nm), the foldamer prefers a tight spiral structure that allows specially configured residues to interact with each other, which improves stability, and creates an attractive pocket for chloride. In the presence of ultraviolet light (365 nm), the foldamer absorbs energy and the tight spiral is destabilized, weakening the chloride binding pocket and freeing chloride to re-enter the solution.

The "light switch" properties of the foldamer could make it an invaluable tool to biochemists and molecular biologists who seek to adjust the availability of chloride in their experiments by simply turning a UV light emitter on or off.

The foldamer is not quite ready for that, however. It can only be dissolved at present in organic (fatty) solutions, whereas living systems operate mostly in water-based solutions.

"That's the direction we're headed," Flood said. "It actually wouldn't be that difficult to modify the molecule so that it is water soluble. But first we need to make sure it does all the things we want it to do."

In their JACS paper, Flood said he and Hua wanted to bring sythentic chemistry together with modern diagnostic approaches to demonstrate the efficacy of their foldamer.

"A lot of the ideas in our paper have been floating around for some time," Flood said. "The idea of a foldamer that binds anions, the idea of a foldamer that you can isomerize with light, the idea of receptor that can bind anions ... But none of the prior work uses conductivity to show that the chloride concentrations actually go up and down as intended. What's new is that we've put all these things together. We think we have something here that allows us to raise our heads to the great research that's preceded us."

Flood and Hua used an electrical conductivity test to show that when voltage is applied to the solution containing chloride ions and the binding molecule, electricity flows more freely in the presence of UV light, when the binder is relaxed and chloride is disassociated from it. That was proof, Flood said, that the foldamer was working as intended.

"My training is in building molecular machines," Flood said. "I create machines that do what we want them to do -- and to show what's possible in chemical and biological laboratory science."

The binding molecule Flood and Hua describe is an improvement on a previous binder developed by Flood and then-postdoctoral fellow Yongjun Li that was also an oligomer of sorts but did not fold. This previous iteration of the chloride binder was closed and donut-shaped, using space restrictions and strategically placed atoms to yield a binding pocket with a special affinity for chloride.

Funding and support for this research were provided by the U.S. Department of Energy's Office of Science and the Camille Dreyfus Teacher-Scholar Award.

To speak with Flood, please contact David Bricker, University Communications, at 812-856-9035 or brickerd@indiana.edu

David Bricker | Newswise Science News
Further information:
http://www.indiana.edu

More articles from Life Sciences:

nachricht Building a brain, cell by cell: Researchers make a mini neuron network (of two)
23.05.2018 | Institute of Industrial Science, The University of Tokyo

nachricht Research reveals how order first appears in liquid crystals
23.05.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

NIST puts the optical microscope under the microscope to achieve atomic accuracy

23.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>