Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Liquid or solid? Charged nanoparticles in lipid membrane decide

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:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

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

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>