Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seeing the action

27.05.2015

UCSB researchers develop a novel device to image the minute forces and actions involved in cell membrane hemifusion

Cells are biological wonders. Throughout billions of years of existence on Earth, these tiny units of life have evolved to collaborate at the smallest levels in promoting, preserving and protecting the organism they comprise.


This is an artist's concept of cell hemifusion.

Credit: Peter Allen

Among these functions is the transport of lipids and other biomacromolecules between cells via membrane adhesion and fusion -- processes that occur in many biological functions, including waste transport, egg fertilization and digestion.

At the University of California, Santa Barbara, chemical engineers have developed a way to directly observe both the forces present and the behavior that occurs during cell hemifusion, a process by which only the outer layers of the lipid bilayer of cell membranes merge.

While many different techniques have been used to observe membrane hemifusion, simultaneous measurements of membrane thickness and interaction forces present a greater challenge, according to Dong Woog Lee, lead author of a paper that appears in the journal Nature Communications.

'It is hard to simultaneously image hemifusion and measure membrane thickness and interaction forces due to the technical limitations,' he said.

However, by combining the capabilities of the Surface Forces Apparatus (SFA) -- a device that can measure the tiny forces generated by the interaction of two surfaces at the sub-nano scale -- and simultaneous imaging using a fluorescence microscope, the researchers were able to see in real time how the cell membranes rearrange in order to connect and open a fusion conduit between them. The SFA was developed in Professor Jacob Israelachvili's Interfacial Sciences Lab at UCSB. Israelachvili is a faculty member in the Department of Chemical Engineering at UCSB.

To capture real time data on the behavior of cell membranes during hemifusion, the researchers pressed together two supported lipid bilayers on the opposing surfaces of the SFA. These bilayers consisted of lipid domains -- collections of lipids that in non-fusion circumstances are organized in more or less regularly occurring or mixed arrangements within the cell membrane.

'We monitored these lipid domains to see how they reorganize and relocate during hemifusion,' said Lee. The SFA measured the forces and distances between the two membrane surfaces as they were pushed together, visualized at the Ångstrom (one-tenth of a nanometer) level. Meanwhile, fluorescent imaging made it possible to see the action as the more ordered-phase (more solid) domains reorganized and allowed the more disordered-phase (more fluid) domains to concentrate at the point of contact.

'This is the first time observing fluorescent images during a hemifusion process simultaneously with how the combined thickness of the two bilayers evolve to form a single layer,' said Lee. This rearrangement of the domains, he added, lowers the amount of energy needed during the many processes that require membrane fusion. At higher pressures, according to the study, the extra energy activates faster hemifusion of the lipid layers.

Lipid domains have been seen in many biological cell membranes, and have been linked to various diseases such as multiple sclerosis, Alzheimer's disease and lung diseases. According to the researchers, this novel device could be used to diagnose, provide a marker for, or study dynamic transformations in situations involving lipid domains in pathological membranes. The fundamental insights provided by this device could also prove useful for other materials in which dynamic changes occur between membranes, including surfactant monolayers and bilayers, biomolecules, colloidal particles, surfactant-coated nanoparticles and smart materials.

Media Contact

Sonia Fernandez
sonia.fernandez@ucsb.edu
805-893-4765

 @ucsantabarbara

http://www.ucsb.edu 

Sonia Fernandez | EurekAlert!

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>