Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Liquid or solid? Charged nanoparticles in lipid membrane decide

11.11.2008
Like water and ice cubes mixed in a glass, a group of organic compounds called lipids can coexist as liquid and solid in membranes. This patchiness in phospholipid membranes is fundamental to their use as biomolecules and biosensors.

Using charged nanoparticles, researchers at the University of Illinois have found a new way to stimulate patchiness in phospholipid membranes.

"We are seeing a previously unsuspected responsiveness in phospholipid membranes," said Steve Granick, a Founder Professor of Engineering at the U. of I. "What we thought was possible only with the specificity of certain proteins, we now see can happen with simple, charged nanoparticles."

Lipids are the building blocks of cell membranes. In earlier work, Granick and graduate student Liangfang Zhang found a way to stabilize sensitive lipid membranes by attaching charged nanoparticles to the membrane surface.

Now, Granick, Zhang, graduate research assistant Bo Wang and research scientist Sung Chul Bae show that a phospholipid membrane can coexist in two phases – solid and liquid – according to what binds to it. This inherent patchiness presents an additional mechanism for changing the stiffness of phospholipid membranes.

The researchers report their work in a paper to be published next week in the Online Early Edition of the Proceedings of the National Academy of Sciences.

Using fluorescence and calorimetry methods, the researchers studied interactions between charged nanoparticles and membranes formed from single-component lipids. Because the membrane was composed of one sole lipid type, the traditional explanation for spatial patchiness – an uneven distribution of different lipids – was eliminated.

While a variety of nanoparticles was used, the most common type was polystyrene spheres about 20 nanometers in diameter (a nanometer is 1 billionth of a meter). Where the nanoparticles attached to the membrane, the membrane responded by changing phase.

"The electric charge acted as a switch," Granick said. "Nanoparticles with a negative charge switched membranes from liquid to solid. Nanoparticles with a positive charge switched the membranes from solid to liquid."

Phase changes occurred in patches of membranes where phospholipid molecules swiveled after binding to charged nanoparticles. This binding-induced behavior, where the same lipid can coexist in two different phases, offers a new mechanism for modulating stiffness in membranes.

In future work, the researchers plan to study the effects of smaller, charged nanoparticles; the effects of charged nanoparticles on living cells; and novel ways to stabilize lipid membranes for targeted drug delivery.

"These experiments are helping us better understand both the structure of phospholipid membranes and the potential biological effects of exposure to nanoparticles found in our normal, everyday environment," Granick said.

James E. Kloeppel | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>