Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cell membranes behave like cornstarch and water

04.11.2010
Researchers dispel the notion that membrane infrastructure is all water like... it can have bounce, too

Mix two parts cornstarch and one part water. Swirl your fingers in it slowly and the mixture is a smoothly flowing liquid. Punch it quickly with your fist and you meet a rubbery solid -- so solid you can jump up and down on a vat of it.

It turns out that cell membranes – or, more precisely the two-molecule-thick lipid sheets that form the structural basis of all cellular membranes -- behave the same way, say University of Oregon scientists.

For decades, researchers have been aware that biological membranes are fluid, and that this fluidity is crucial to allowing the motions and interactions of proteins and other cell surface molecules. The new studies, however, reveal that this state is not the simple Newtonian fluidity of familiar liquids like water, but rather it is viscoelastic. At rest the mixture is very fluid, but when quickly perturbed, it bounces back like rubber.

The discovery -- detailed Oct. 25 in the Early Edition of the Proceedings of the National Academy of Sciences -- strikes down the notion that these biologically important membranes are Newtonian fluids that flow regardless of the stress they encounter.

"This changes our whole understanding of what lipid membranes are," said Raghuveer Parthasarathy, a professor of physics and member of the UO's Materials Science Institute and Institute of Molecular Biology. "We may need to rethink our understanding of how all sorts of the mechanical processes that occur in cell membranes work, like how proteins are pulled from one place to another, how cells respond to stretching and other forces, and how membrane-embedded proteins that serve as channels for chemical signals are able to open and close.

"A lot of these mechanical tasks go awry in various diseases for reasons that remain mysterious," he said. "Perhaps a deeper understanding of the mechanical environment that membranes provide will illuminate why biology functions, or fails to function, in the way it does."

In the project, freestanding membranes of lipids -- fatty molecules that form the basis of all cell membranes -- were built with lipid-anchored nanoparticles as tracers that could be observed under high-powered microscopes. Close analysis of the trajectories of these particles allowed researchers to deduce the fluid and elastic properties of the membranes under changing conditions.

Leading the experiments were Christopher W. Harland, who earned a doctorate in physics from the UO last summer and is now a postdoctoral researcher at the University of Chicago, and Miranda J. Bradley, then a visiting undergraduate student from Portland Community College and now at Portland State University. Bradley studied in Parthasarathy's lab as part of the UO's Undergraduate Catalytic Outreach & Research Experiences (UCORE) program.

The importance of membrane fluidity has been recognized for decades, but membranes' strange character as a viscoelastic material has gone unnoticed, said Parthasarathy, who is among UO scientists involved in the Oregon Nanoscience and Microtechnologies Institute (ONAMI). "In retrospect, we shouldn't be surprised. Nature uses viscoelasticity in lots of its other liquids, from mucus to tears. Now we've found that it harnesses viscoelasticity in lipid membranes as well."

The Alfred P. Sloan Foundation, Office of Naval Research through ONAMI and National Science Foundation supported the research.

About the University of Oregon

The University of Oregon is a world-class teaching and research institution and Oregon's flagship public university. The UO is a member of the Association of American Universities (AAU), an organization made up of the 63 leading public and private research institutions in the United States and Canada. The UO is one of only two AAU members in the Pacific Northwest.

Source: Raghuveer Parthasarathy, assistant professor of physics, 541-346-2933, raghu@uoregon.edu

Links:

YouTube Video:
http://www.youtube.com/watch?v=zB-gzgrhVUk
Parthasarathy website:
http://physics.uoregon.edu/faculty/raghu.html
Physics department:
http://physics.uoregon.edu/
Materials Science Institute:
http://materialscience.uoregon.edu/
Institute of Molecular Biology:
http://molbio.uoregon.edu/
ONAMI:
http://www.onami.us/
UO Science on Facebook:
http://www.facebook.com/UniversityOfOregonScience

Jim Barlow | EurekAlert!
Further information:
http://www.uoregon.edu

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>