Harvard engineering team fabricates new and improved optical tweezer

February 26, 2008, Cambridge, MA--Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have 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 18 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 100x100 microns.

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.

Get All the BioOptics World News Delivered to Your Inbox

Subscribe to BioOptics World Magazine or email newsletter today at no cost and receive the latest news and information.

 Subscribe Now
Related Articles

FDA authorizes emergency use of Zika virus molecular detection assay

The xMAP MultiFLEX Zika RNA assay combines optofluidics and digital signal processing to detect Zika virus in vitro.

'Lab on a stick' test optically and rapidly detects antibiotic resistance

A point-of-care test, based on the dipstick method, can rapidly detect bacterial resistance to antibiotics in urine.

Merz acquires laser tattoo removal device maker ON Light Sciences

Merz North America has acquired ON Light Sciences, which develops technologies to enhance laser-based dermatology procedures.

New bioimaging technique offers clear view of nervous system

Scientists at Ludwig-Maximilians University have developed a technique for turning the body of a deceased rodent entirely transparent, revealing the central nervous system in unprecedented clarity....
BLOGS

Neuro15 exhibitors meet exacting demands: Part 2

Increasingly, neuroscientists are working with researchers in disciplines such as chemistry and p...

Why be free?

A successful career contributed to keeping OpticalRayTracer—an optical design software program—fr...

LASER Munich 2015 is bio-bent

LASER World of Photonics 2015 included the European Conferences on Biomedical Optics among its si...

White Papers

Understanding Optical Filters

Optical filters can be used to attenuate or enhance an image, transmit or reflect specific wavele...

How can I find the right digital camera for my microscopy application?

Nowadays, image processing is found in a wide range of optical microscopy applications. Examples ...

CONNECT WITH US

            

Twitter- BioOptics World

Copyright © 2007-2016. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS