Integrated optical trap holds particles for on-chip analysis

June 30, 2009
The integrated optical trap allows independent manipulation of trapped microbeads as shown in this view of two microbeads trapped by two different dual-beam traps. Image courtesy of H. Schmidt.

(PhysOrg.com) -- A new type of optical particle trap can be used to manipulate bacteria, viruses and other particles on a chip as part of an integrated optofluidic platform. The optical trap is the latest innovation from researchers at the Jack Baskin School of Engineering at the University of California, Santa Cruz, who are developing new sensor technology for biomedical analysis and other applications.

"Ultimately, it could have applications for rapid detection of bacteria and viruses in hospitals, for cell sorting in research labs, and for process monitoring in chemical engineering," said Holger Schmidt, professor of electrical engineering and director of the W. M. Keck Center for Nanoscale Optofluidics at UCSC.

The new technique offers the potential to create a smaller, cheaper version of the sophisticated equipment used to perform fluorescence-activated cell sorting (FACS), Schmidt said.

"The capabilities of our optofluidic platform are continuing to grow. We have gone from the detection of single molecules and single viruses to now being able to control the movement of particles," he said.

Schmidt's group has received a $400,000 grant from the National Institutes of Health to explore particle trapping and sorting and other applications of the optofluidics platform. An article describing the optical trap for on-chip particle analysis has been published online by the journal Lab on a Chip. First author Sergei Kuhn was a postdoctoral researcher in Schmidt's lab and is now at the Max-Born Institute in Berlin. Coauthors include David Deamer and Philip Measor at UCSC and E. J. Lunt, B. S. Phillips, and A. R. Hawkins of Brigham Young University, where the optofluidic chips are fabricated.

Optical traps and "" use the momentum carried by the photons in a beam of light to exert forces on microscopic objects, enabling researchers to manipulate objects ranging from biological molecules to living cells. Schmidt's group developed a new way to perform optical trapping on a chip-based platform.

The technique relies on an earlier innovation from Schmidt's lab: a hollow-core optical waveguide that can direct a beam of light through a liquid-filled channel on a chip. To trap particles, the researchers used two laser beams at opposite ends of a channel. A particle gets trapped at the point where the forces exerted by the two beams are equal, and the particle can be moved by changing the relative power of the two laser beams.

"We can also use this like an optical leaf blower to push all the particles in a sample to the same spot and increase the concentration," Schmidt said. "The goal is to control the position and movement of particles through channels on a chip so they can be studied using fluorescence analysis and other optical methods."

Provided by University of California, Santa Cruz

Explore further: White-light laser is basis of new optical tweezers and microscope

Related Stories

Researchers achieve atomic spectroscopy on a chip

June 1, 2007

Researchers at the University of California, Santa Cruz, have performed atomic spectroscopy with integrated optics on a chip for the first time, guiding a beam of light through a rubidium vapor cell integrated into a semiconductor ...

Team 'tractor beam' for manipulation of cells on silicon

October 30, 2007

In a feat that seems like something out of a microscopic version of Star Trek, MIT researchers have found a way to use a “tractor beam” of light to pick up, hold, and move around individual cells and other objects on ...

Researchers demonstrate a new type of optical tweezer

February 25, 2008

Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) demonstrated a new type of optical tweezer with the potential to make biological and microfluidic force measurements in integrated systems such ...

Using light to move and trap DNA molecules

January 2, 2009

(PhysOrg.com) -- A major goal of nanotechnology research is to create a "lab on a chip," in which a tiny biological sample would be carried through microscopic channels for processing. This could make possible portable, fast-acting ...

Recommended for you

Graphene under pressure

August 25, 2016

Small balloons made from one-atom-thick material graphene can withstand enormous pressures, much higher than those at the bottom of the deepest ocean, scientists at the University of Manchester report.

Designing ultrasound tools with Lego-like proteins

August 25, 2016

Ultrasound imaging is used around the world to help visualize developing babies and diagnose disease. Sound waves bounce off the tissues, revealing their different densities and shapes. The next step in ultrasound technology ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.