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Press Release 05-123

High-Tech Tool Maneuvers Microscopic Particles

Optical conveyor belt moves 15,000 micron-sized objects all at once

Walls of light confine and transport tiny particles on an optical conveyor belt.
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Walls of light confine and transport tiny particles on an optical conveyor belt.
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July 20, 2005

Researchers have invented so-called optoelectronic tweezers that can maneuver microscopic particles as small as living cells without damaging them. The tool uses optical energy from a low-intensity laser beam to create an electric field on a photoconductive glass slide. Similar to magnets sticking together or pushing apart according to their orientation, a particle inside the charged electric field is attracted or repelled depending on its own charge. Moving the laser beam moves the electric field, taking the object along with it.

University of California, Berkeley professor, Ming Wu, together with graduate students Pei Yu Chiou and Aaron Ohta, describe the new device in the July 21 issue of the journal, Nature.

The light from the laser can be projected into a variety of shapes and sizes providing imaginative scientists with all sorts of possibilities for moving, sorting and trapping micron-sized objects. Wu has even developed an optical conveyor belt with individual compartments to transport particles.

Ohta, whose research and training is supported by the National Science Foundation, works closely with Chiou on this project. Together, they were graduate finalists in the 2004 Collegiate Inventors Competition. The international contest, sponsored by the U.S. Patent and Trademark Office, encourages students to actively practice science, engineering and mathematics for creative invention of patentable products.

For more information, see the complete story at the University of California, Berkeley news center.


Media Contacts
Richard (Randy) Vines, NSF, (703) 292-7963,
Sarah Yang, University of California, Berkeley, (510) 643-7741,

Principal Investigators
Ming Wu, University of California, Berkeley, 510 643-0808,

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2016, its budget is $7.5 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives more than 48,000 competitive proposals for funding and makes about 12,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.

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