Featured Research

from universities, journals, and other organizations

New Type Of Tiny Optical Tweezer Developed

Date:
March 3, 2008
Source:
Harvard University
Summary:
A new type of optical tweezer with the potential to make biological and microfluidic force measurements in integrated systems such as microfluidic chips has been developed. The tweezer, consisting of a Fresnel Zone Plate microfabricated on a glass slide, has the ability to trap particles without the need for high performance objective lenses.

(a). Photograph of microfabricated Fresnel Zone Plate optical tweezer, consisting of concentric gold rings (50 nm thick) on a microscope slide. The Zone Plate outer diameter is 100m, and the focal length is 8m. (b). CCD camera image of fluorescent bead (2m diameter) trapped in Zone Plate focus.
Credit: Ken Crozier, Harvard School of Engineering and Applied Sciences

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 as microfluidic chips. The tweezer, consisting of a Fresnel Zone Plate microfabricated on a glass slide, has the ability to trap particles without the need for high performance objective lenses.

The device was designed, fabricated, and tested by postdoctoral fellow Ethan Schonbrun and undergraduate researcher Charles Rinzler under the direction of Assistant Professor of Electrical Engineering Ken Crozier (all are affiliated with SEAS). The team's results were published in the February 18th edition of Applied Physics Letters and the researchers have filed a U.S. provisional patent covering this new device.

"The microfabricated nature of the new optical tweezer offers an important advantage over conventional optical tweezers based on microscope objective lenses," says Crozier. "High performance objective lenses usually have very short working distances -- the trap is often ~200 mm or less from the front surface of the lens. This prevents their use in many microfluidic chips since these frequently have glass walls that are thicker than this."

The researchers note that the Fresnel Zone Plate optical tweezers could be fabricated on the inner walls of microfluidic channels or even inside cylindrical or spherical chambers and could perform calibrated force measurements in a footprint of only 100x100m.

Traditional tweezers, by contrast, would suffer from crippling aberrations in such locations. Moreover, in experimental trials, the optical tweezers exhibited trapping performance comparable to conventional optical tweezers when the diffraction efficiency was taken into account.

The researchers envision using their new tweezer inside microfluidic chips to carry out fluid velocity, refractive index, and local viscosity measurements. Additional applications include biological force measurements and sorting particles based on their size and refractive index. Particle-sorting chips based on large arrays of tweezers could be used to extract the components of interest of a biological sample in a high-throughput manner.

The work was supported by the Microsystems Technology Office of the Defense Advanced Research Projects Agency and the Harvard Nanoscale Science and Engineering Center of the National Science Foundation.


Story Source:

The above story is based on materials provided by Harvard University. Note: Materials may be edited for content and length.


Cite This Page:

Harvard University. "New Type Of Tiny Optical Tweezer Developed." ScienceDaily. ScienceDaily, 3 March 2008. <www.sciencedaily.com/releases/2008/02/080225101114.htm>.
Harvard University. (2008, March 3). New Type Of Tiny Optical Tweezer Developed. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2008/02/080225101114.htm
Harvard University. "New Type Of Tiny Optical Tweezer Developed." ScienceDaily. www.sciencedaily.com/releases/2008/02/080225101114.htm (accessed July 22, 2014).

Share This




More Matter & Energy News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins