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 A new potential biomarker for cancer imaging
05.02.2016 | Universiti Putra Malaysia (UPM)

nachricht NIH researchers identify striking genomic signature shared by 5 types of cancer
05.02.2016 | NIH/National Human Genome Research Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Automated driving: Steering without limits

OmniSteer project to increase automobiles’ urban maneuverability begins with a € 3.4 million budget

Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...

Im Focus: Microscopy: Nine at one blow

Advance in biomedical imaging: The University of Würzburg's Biocenter has enhanced fluorescence microscopy to label and visualise up to nine different cell structures simultaneously.

Fluorescence microscopy allows researchers to visualise biomolecules in cells. They label the molecules using fluorescent probes, excite them with light and...

Im Focus: NASA's ICESat-2 equipped with unique 3-D manufactured part

NASA's follow-on to the successful ICESat mission will employ a never-before-flown technique for determining the topography of ice sheets and the thickness of sea ice, but that won't be the only first for this mission.

Slated for launch in 2018, NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) also will carry a 3-D printed part made of polyetherketoneketone (PEKK),...

Im Focus: Sinking islands: Does the rise of sea level endanger the Takuu Atoll in the Pacific?

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister...

Im Focus: Energy-saving minicomputers for the ‘Internet of Things’

The ‘Internet of Things’ is growing rapidly. Mobile phones, washing machines and the milk bottle in the fridge: the idea is that minicomputers connected to these will be able to process information, receive and send data. This requires electrical power. Transistors that are capable of switching information with a single electron use far less power than field effect transistors that are commonly used in computers. However, these innovative electronic switches do not yet work at room temperature. Scientists working on the new EU research project ‘Ions4Set’ intend to change this. The program will be launched on February 1. It is coordinated by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR).

“Billions of tiny computers will in future communicate with each other via the Internet or locally. Yet power consumption currently remains a great obstacle”,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

DATE 2016 Highlighting Automotive and Secure Systems

26.01.2016 | Event News

 
Latest News

A new potential biomarker for cancer imaging

05.02.2016 | Life Sciences

Graphene is strong, but is it tough?

05.02.2016 | Materials Sciences

Tiniest Particles Shrink Before Exploding When Hit With SLAC's X-ray Laser

05.02.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>