New Type Of Optical Tweezer Demonstrated By Engineers
Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) demonstrated a new emblem of optical tweezer with the potential to make biological and microfluidic force measurements in integrated systems similar 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 exalted 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 gain 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 defective working distances — the snare is repeatedly ~200 mm or less from the make a front to 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 pincers 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 100×100μm.
Traditional tweezers, by the agency of contrast, would suffer from crippling aberrations in such locations. Moreover, in experimental trials, the optical tweezers exhibited trapping performance comparable to common 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 energy measurements and sorting particles based forward their size and refractive index. Particle-sorting chips based on broad arrays of tweezers could have being used to draw out the components of interest of a biological sample in a high-throughput manner.
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Article adapted by Medical News Today from eccentric person press let go.
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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.
Source: Michael Patrick Rutter
Harvard University
April 6th, 2008 at 11:26 pm
It’s amazing. I like it. Sounds good to me, even though I can’t agree with everything< that is written here
April 9th, 2008 at 5:57 pm
Looks perfectly straight to me. Of course, I’m also the type of person who allegedly [ahem! allegedly] agree with everything.