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Apparatus and method for concentrating and filtering particles suspended in a fluid

United States Patent

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May 19, 2009
View the Complete Patent at the US Patent & Trademark Office
Insulating Dielectrophoresis (iDEP)
Microfluidic Devices
Disclosed is a device for separating and concentrating particles suspended in a fluid stream by using dielectrophoresis (DEP) to trap and/or deflect those particles as they migrate through a fluid channel. The method uses fluid channels designed to constrain a liquid flowing through it to uniform electrokinetic flow velocities. This behavior is achieved by connecting deep and shallow sections of channels, with the channel depth varying abruptly along an interface. By careful design of abrupt changes in specific permeability at the interface, an abrupt and spatially uniform change in electrokinetic force can be selected. Because these abrupt interfaces also cause a sharp gradient in applied electric fields, a DEP force also can be established along the interface. Depending on the complex conductivity of the suspended particles and the immersion liquid, the DEP force can controllably complement or oppose the local electrokinetic force transporting the fluid through the channel allowing for manipulation of particles suspended in the transporting liquid.
Fiechtner; Gregory J. (Bethesda, MD), Cummings; Eric B. (Livermore, CA), Singh; Anup K. (Danville, CA)
Sandia Corporation (Livermore, CA)
September 30, 2004
204/547 ; 204/451; 422/527; 436/180;
B01D 57/02 (20060101); B01L 11/00 (20060101); B01D 59/42 (20060101);
STATEMENT OF GOVERNMENT INTEREST This invention was made with Government support under government contract no. DE-AC04-94AL85000 awarded by the U.S. Department of Energy to Sandia Corporation. The Government has certain rights in the invention, including a paid-up license and the right, in limited circumstances, to require the owner of any patent issuing in this invention to license others on reasonable terms.