Navigation Links
'Two-Faced' Particles Act Like Tiny Submarines
Date:2/29/2008

RALEIGH, N.C., Feb. 29 /PRNewswire-USNewswire/ -- For the first time, researchers at North Carolina State University have demonstrated that microscopic "two-faced" spheres whose halves are physically or chemically different -- so-called Janus particles -- will move like stealthy submarines when an alternating electrical field is applied to liquid surrounding the particles.

A paper describing the research, published in the Feb. 8, 2008, edition of Physical Review Letters, advances knowledge about how potential "smart" materials -- think of tiny engines or sensors -- can move around and respond to changes in their environment. Janus particles could be used as microscopic mixers, molecular "shuttles," self-propelling microsensors or means of targeted drug delivery.

The researchers -- Dr. Orlin Velev, associate professor of chemical and biomolecular engineering at NC State and lead author of the paper; Sumit Gangwal, an NC State graduate student; Dr. Olivier Cayre, a post-doctoral researcher in Velev's lab; and Dr. Martin Bazant from Massachusetts Institute of Technology -- created tiny two-faced gold and plastic particles and applied low frequency alternating current to the water containing the particles. The electric field was of voltage and frequency similar to the ones you'd get if you plugged a device into a socket in your home or office.

Velev says the micrometer-sized particles convert the electrical field into liquid motion around them and then unexpectedly propel themselves perpendicular to the direction of the powered electrodes -- not in the direction of the electrical field, as would be expected. The particles always travel in the same orientation: with the plastic "face" as the front of the mini-submarine and the metallic "face" in the rear, Velev added.

The phenomenon -- called "induced-charge electrophoresis," which had been predicted in a theoretical model by the MIT collaborator -- had not been demonstrated previously.

The term "Janus particle" comes from the name of a Roman god with two faces. Velev says that these materials have the potential to perform a variety of applications.

"You can imagine other types of Janus particles comprising a 'smart gel' that responds to a change in its environment and then releases drugs, for example," Velev says. Fabricating these responsive materials on the microscale and nanoscale is an exciting and rapidly developing area of science, he adds.

"We are able to create tiny Janus particles of the same size and shape and are beginning to learn how to give them functionality," Velev said. "The next step is to create more complex particles that are able to perform more specialized functions in addition to propelling themselves around."

The research is funded by the National Science Foundation and a Camile and Henry Dreyfus Teacher-Scholar grant.

Note to editors: The abstract of the paper follows.

"Induced Charge Electrophoresis of Metallodielectric Particles"

Authors: Sumit Gangwal, Olivier J. Cayre and Dr. Orlin D. Velev, NC State University; Dr. Martin Z. Bazant, Massachusetts Institute of Technology Published: Feb. 4, 2008, in Physical Review Letters

Abstract: The application of ac electric fields in aqueous suspensions of anisotropic particles leads to unbalanced liquid flows and nonlinear, induced-charge electrophoretic motion. We report experimental observations of the motion of Janus microparticles with one dielectric and one metal-coated hemisphere induced by uniform fields of frequency 100Hz-10kHz in NaCl solutions. The motion is perpendicular to the field axis and persists after particles are attracted to a glass wall. This phenomenon may find application in microactuators, microsensors and microfluidic devices.

Dr. Orlin Velev, (919) 513-4318 or odvelev@unity.ncsu.edu

This news release was issued on behalf of Newswise(TM). For more information, visit http://www.newswise.com.


'/>"/>
SOURCE North Carolina State University
Copyright©2008 PR Newswire.
All rights reserved

Related biology technology :

1. Two-faced miniatures
2. 2-faced particles act like tiny submarines
3. Strengthening fluids with nanoparticles
4. DNA technique yields 3-D crystalline organization of nanoparticles
5. Anthrax vaccine produces immunity with nanoparticles, not needles
6. New DNA-based technique for assembly of nano- and micro-sized particles
7. CeloNova BioSciences Announces Worlds First Line of Fully Color-Coded Embolic Particles at CIRSE: Embozene(TM) Color-Advanced Microspheres
8. Anthrax vaccine produces immunity with nanoparticles, not needles
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/23/2016)... , June 23, 2016   EpiBiome , a ... $1 million in debt financing from Silicon Valley Bank ... automation and to advance its drug development efforts, as ... facility. "SVB has been an incredible strategic ... services a traditional bank would provide," said Dr. ...
(Date:6/23/2016)... NEWPORT BEACH, Calif. , June 23, 2016 /PRNewswire/ ... offering new biological discoveries to the medical community, has ... and co-founder Matthew Nunez . "We ... provide us with the capital we need to meet ... funding will essentially provide us the runway to complete ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... a new line of intelligent tools designed, tuned and optimized exclusively for Okuma ... 12–17 in Chicago. The result of a collaboration among several companies with expertise ...
(Date:6/22/2016)... , June 22, 2016  According to Kalorama ... generation sequencing (NGS) market include significant efforts in ... sequencers.  More accessible and affordable sequencers, say the ... demand for consumables including sample prep materials.  The ... for Sample Preparation for Next Generation Sequencing (NGS) ...
Breaking Biology Technology:
(Date:4/28/2016)... SAN FRANCISCO and BANGALORE, India ... part of EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... service provider, today announced a global partnership that ... convenient way to use mobile banking and payment services. ... Mobility is a key innovation area for financial services, but ...
(Date:4/26/2016)... BANGALORE, India and LONDON ... Infosys Finacle, part of EdgeVerve Systems, a ... ), and Onegini today announced a partnership to ... banking solutions.      (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ... banks to provide their customers enhanced security to ...
(Date:4/19/2016)... , UAE, April 20, 2016 ... be implemented as a compact web-based "all-in-one" system solution ... the biometric fingerprint reader or the door interface with ... of modern access control systems. The minimal dimensions of ... ID readers into the building installations offer considerable freedom ...
Breaking Biology News(10 mins):