Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MIT reveals inner lives of red blood cells

24.10.2006
Work could aid research on sickle cell anemia and malaria

For the first time, researchers at MIT can see every vibration of a cell membrane, using a technique that could one day allow scientists to create three-dimensional images of the inner workings of living cells.

Studying cell membrane dynamics can help scientists gain insight into diseases such as sickle cell anemia, malaria and cancer. Using a technique known as quantitative phase imaging, researchers at MIT's George R. Harrison Spectroscopy Laboratory can see cell membrane vibrations as tiny as a few tens of nanometers (billionths of a meter).

But cell membrane dynamics are just the beginning.

Soon, the researchers hope to extend their view beyond the cell membrane into the cell, to create images of what is happening inside living cells -- including how cells communicate with each other and what causes them to become cancerous.

"One of our goals is create 3D tomographic images of the internal structure of a cell," said Michael Feld, MIT professor of physics and director of the Spectroscopy Lab. "The beauty is that with this technique, you can study dynamical processes in living cells in real time."

Scientists have long been able to peer into cells using electron microscopy, which offers a much higher magnification than a traditional light microscope. However, electron microscopy can only be used on cells that are dehydrated, frozen or treated in other ways. Thus it cannot be used to view living cells.

Quantitative phase imaging, on the other hand, allows researchers to observe living cells for as long a time period as they want. After years of fine tuning, the MIT researchers can now create images with a resolution of 0.2 nanometers. (A red blood cell has a diameter of about 8 microns, or 8,000 nanometers.)

So far, the team has focused its attention primarily on red blood cells and neurons. Red blood cells are an especially good model to study cell membrane dynamics because they are relatively simple cells, with no nuclei or internal cell structures, says Gabriel Popescu, a postdoctoral associate in the Spectroscopy Lab.

In work that is soon to be published in Physical Review Letters, the MIT researchers show that the frequency of cell membrane vibration is related to the elasticity of the cell membrane. Elasticity is important for red blood cells because they have to be able to squeeze through tiny capillaries in the brain and elsewhere, as they deliver oxygen.

"The elasticity of these cells is crucial for their function," said Popescu.

It has been known for more than a century that red blood cell membranes are continuously undulating, or as Popescu puts it, a red blood cell is "effectively a drum in perpetual vibration." This undulation offers a chance to study the mechanical properties of the membrane, including how the membrane provides the cell with both the softness and the elasticity needed to squeeze through narrow capillaries.

Red blood cell abnormalities, such as the twisting deformation seen in sickle cell anemia, also influence membrane dynamics. The researchers are now studying how sickle cell anemia and malaria infection affect the mechanical properties of red blood cell membranes.

Popescu gave a talk on the blood cell work earlier this month at a meeting of the Optical Society of America.

Another group in the Spectroscopy Lab is studying signal propagation in neurons. This project, a collaboration with Sebastian Seung, a professor of brain and cognitive sciences, and led by Chris Fang-Yen, a postdoctoral associate in the Spectroscopy Laboratory, is based on the fact that membranes undergo tiny mechanical deformations when an action potential (electrical current) travels along the neuron's axon.

The correlation between membrane vibration and electrical activity could "give us insight on how networks are organized on a neuron level," said Fang-Yen. They are especially interested in studying neural networks in the hippocampus, a brain area associated with memory.

Quantitative phase imaging builds on an optical phenomenon known as interferometry. With this method, a light wave passing through the cell is compared with a reference wave that doesn't pass through the sample. Combining those two waves creates an interference pattern that offers nanometer-scale images of individual cells.

The major problem with interferometry is that the apparatus is highly sensitive. Even breathing near the interferometer can disrupt the system, leading Popescu to observe that in a typical laboratory environment, trying to measure such tiny optical signals is "like trying to sense the waves of a jellyfish in a stormy ocean."

One way to overcome that is to mount the system in an isolated environment. Another technique, known as the "common path" approach, places both arms of the interferometer (through which the light waves are traveling) in close proximity so the noise in the signals cancel each other out.

Quantitative phase imaging has not yet reached the level of resolution that electron microscopy offers, but Feld said he believes it will someday.

Other Spectroscopy Laboratory researchers involved in the work are Wonshik Choi, a postdoctoral associate; Ramachandra Dasari, principal research scientist; Kamran Badizadegan, a faculty member in the MIT-Harvard Division of Health Sciences and Technology; Shahrooz Amin, a graduate student in electrical engineering and computer science; Seungeun Oh, a graduate student in physics; YongKeun Park, a graduate student in mechanical engineering; and Niyom Lue, a graduate student at the University of Massachusetts College of Engineering.

Michael Laposata and Catherine Best Popescu from Massachusetts General Hospital are also collaborating on the red blood cell studies.

This work was funded by the National Institutes of Health and Hamamatsu Photonics.

Elizabeth A. Thomson | MIT News Office
Further information:
http://www.mit.edu

Further reports about: Dynamics Neuron Popescu Researchers anemia mechanical spectroscopy

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 >>>