Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Using water molecules to read electrical activity in lipid membranes

03.04.2018

Every human cell is encased in a five-nanometer-thick lipid membrane that protects it from the surrounding environment. Like a gatekeeper, the membrane determines which ions and molecules can pass through. In so doing, it ensures the cell's well-being and stability and allows it to communicate via electrical signals.

Researchers from the Laboratory for fundamental BioPhotonics (LBP) in EPFL's School of Engineering were able to track these moving charges in real time in a completely non-invasive manner. Rather than observing the membranes themselves, they looked at the surrounding water molecules, which, in addition to keeping the membrane intact, change orientation in the presence of electrical charges. So by 'reading' their position, the researchers were able to create a dynamic map of how charges are transported across a membrane.


EPFL researchers were able to map out in real time how charges are transported across and along membranes simply by observing the behavior of adjacent water molecules.

Credit: Jamani Caillet/EPFL

The researchers' method has just been published in the journal Proceedings of the National Academy of Sciences (PNAS). It could shed light on how ion channels function, along with other processes at work in membranes. This clinically viable method could potentially also be used to directly track ion activity in neurons, which would deepen researchers' knowledge of how nerve cells work. "Water molecules can be found wherever there are lipid membranes, which need these molecules to exist," says Sylvie Roke, head of the LBP. "But until now, most studies on membranes didn't look at these molecules. We've shown that they contain important information."

The researchers did this by using a unique second-harmonic microscope that was invented at the LBP. The imaging efficiency of this microscope is more than three orders of magnitude greater than that of existing second-harmonic microscopes. With this microscope, the researchers obtained images of water molecules at a time scale of 100 milliseconds.

To probe the lipid membranes' hydration, the researchers combine two lasers of the same frequency (femtosecond pulses) in a process that generates photons with a different frequency: this is known as second-harmonic light. It is generated only at interfaces and reveals information on the orientation of water molecules. "We can observe what's happening in situ, and we don't need to modify the environment or use bulky markers like fluorophores that would disturb water molecules' movement" says Orly Tarun, the publication's lead author.

Unexpected charge fluctuations are observed

With this method, the researchers observed charge fluctuations in membranes. Such fluctuations were previously unknown and hint at much more complex chemical and physical behavior than is currently considered.

###

Reference: O. Tarun, C. Hannesschläger, P. Pohl, and S. Roke, A label-free and charge-sensitive dynamic imaging of lipid membrane hydration on millisecond time scales, PNAS

Laboratory of fundamental BioPhotonics (LBP) - Julia Jacobi Chair of Photomedicine

Media Contact

Sylvie Roke
sylvie.roke@epfl.ch
41-216-931-191

 @EPFL_en

http://www.epfl.ch/index.en.html 

Sylvie Roke | EurekAlert!

More articles from Life Sciences:

nachricht Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>