Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

With optical ’tweezers,’ researchers pinpoint the rhythmic rigidity of cell skeletons

04.12.2003


Laser tool makes it possible to study the interior of an endothelial cell in a non-invasive way



Endothelial cells, which line the body’s blood vessels and regulate the exchange of material between the blood stream and surrounding tissue, are one of the most closely studied types of cell in the body.

The cells play an important role in cardiovascular disease. And a greater knowledge of their interior functions may help scientists develop new cancer treatments that curb or suppress the growth of tumors by cutting off their blood supply.


Daniel Ou-Yang’s research group at Lehigh University is the first to use a laser tool known as optical tweezers to study the interior of an endothelial cell in a non-invasive way without introducing foreign particles into the cell or around it.

Achieving a resolution of 0.5 microns, Ou-Yang and his group can pinpoint and "trap" an organelle - a specialized part of a cell that resembles and functions like an organ - without damaging it.

They have discovered that the rigidity of the cytoskeleton, or cell skeleton, in the vicinity of the cell’s organelles, appears to change by a factor of four in a rhythmical pattern with a periodicity of 20 to 30 seconds.

"This rhythm tells us something is alive," says Ou-Yang, a professor of physics, co-director of Lehigh’s bioengineering program and a member of Lehigh’s Center for Optical Technologies. "But it raises other questions. What triggers this rhythm? And what is its significance?"

Ou-Yang is collaborating with Linda Lowe-Krentz, professor of biological sciences. He also works with Profs. Ivan Biaggio and Volkmar Dierolf of the physics department and the COT, who specialize in the advanced imaging techniques necessary to measure the intracellular molecular signals.

Dierolf incorporates Raman spectroscopy scattering to see molecules without labeling (dyeing) them. Biaggio measure the mechanical properties of cells using nonlinear optical effects, which generate ultrasound waves to measure mechanical properties.

The work of Ou-Yang, Biaggio and Dierolf is supported by the COT. Ou-Yang and Lowe-Krentz are seeking a grant from the National Science Foundation.

Ou-Yang’s group also includes several students. Meron Mengistu is a graduate student in molecular biology. Elizabeth Rickter, a graduate student in physics, was the first person to observe the rhythmic behaviors that appear to originate from endothelial cytoskeletons. And Laura Morkowchuk, a sophomore bioengineering major, is studying the effect of the cytoskeletal rhythm on the transport of proteins from the blood stream to a cell’s interior substrate tissues.

The overall goal of Ou-Yang’s group is to understand the mechanisms and functions of a cell in a quantitative way, and to map cell functions as scientists have already mapped such major body functions as respiration and digestion.

Ou-Yang has used optical tweezers in his research for more than 10 years, and is one of the pioneers in the technique. The tweezers, also called laser tweezers or optical traps, focus a laser beam through an optical microscope to trap micron-sized dielectric objects, which can then be manipulated by externally steering the laser beams.

Optical tweezers can pinpoint organelles at a resolution of 0.5 microns. The resulting vibration of the cell part is 0.5 nanometers, a measurement that Ou-Yang’s group makes with an innovative application of optical diffraction.

The researchers are interested in cytoskeletal rigidity for several reasons. The cytoskeleton plays an important role in cell division. If scientists can learn how to suppress the rearrangement of the cytoskeleton that is necessary for mitosis to occur, they might be able to obstruct the growth of cancerous tumors, which depends on the often runaway rate of mitosis in cancerous cells.

Cytoskeletal rigidity has also been observed as a response to the chemical treatments used on cancer patients, Ou-Yang says. And tumor growth can be choked by depriving cancer cells of their blood supply, which is regulated by endothelial cells.

Two other Lehigh students have contributed to Ou-Yang’s work with laser tweezers. Larry Hough, who received his Ph.D. in physics in August, is now a research scientist at the University of Pennsylvania. Megan Valentine, earned a B.S. in physics from Lehigh in 1996, recently completed a Ph.D. in physics at Harvard, and is going to Stanford to become a research scientist in biophysics.

Kurt Pfitzer | EurekAlert!
Further information:
http://www.lehigh.edu/

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

Metallic nanoparticles will help to determine the percentage of volatile compounds

20.10.2017 | Materials Sciences

Shallow soils promote savannas in South America

20.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>