Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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


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:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

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...

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

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

Fluorescent holography: Upending the world of biological imaging

25.10.2016 | Power and Electrical Engineering

Etching Microstructures with Lasers

25.10.2016 | Process Engineering

More VideoLinks >>>