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Research in Microfluidic Transport at Sandia National Laboratories

Insulative (Electrodless)
Dielectrophoresis (iDEP) of Live and Dead E.Coli

Live and dead E.Coli
Live and dead E.Coli

Dielectrophoresis separates the living from the dead. Live and dead E. coli, respectively labeled to fluoresce green and red, collect into separate bands when a voltage of 600 V/cm is applied across a microfabricated array of 200-micron diameter circular posts. Being less conductive than the liquid, flowing around them from right to left, these bacteria particles are dielectrophoretically repelled from the electric field concentration that occurs between the posts. Because live cells have a membrane that is less conductive than that of dead cells, they are more strongly repelled. This results in a clear and dramatic separation between the live and dead cells.

This phenomena is being used by Blanca Lapizco, Blake Simmons, Yolanda Fintschenko, and Eric Cummings to make a selective concentrator for live pathogens in drinking water for an E&CI (Energy and Critical Infrastructure) LDRD.

As for the green cells in the red zones---well, even happy California E. coli do not live forever.

Recent Refereed Publications

 

Lapizco Encinas, B.H., Simmons, B.A., Cummings, E.B., Fintschenko, Y.
Insulator-Based Dielectrophoresis for the Selective Concentration and Separation of Live Bacteria in Water,
Electrophoresis, 25, 1695-1704, 2004.

 

Cummings, E.
Streaming Dielectrophoresis for Continuous-Flow Microfluidic Devices
IEEE Eng. Med. Biol. Mag. 22, 75-84, 2003

 

Lapizco Encinas, B.H., Simmons, B.A., Cummings, E.B., Fintschenko,Y.
Dielectrophoretic Concentration and Separation of Live and Dead Bacteria in an Array of Insulators
Analytical Chemistry, 76 (6), 1571-1579, 2004.
Publication awarded with the cover of the journal.

 

Cummings, E. B.; Singh, A. K.;
Dielectrophoresis in Microchips Containing Arrays of Insulating Posts: Theoretical and Experimental Results
Anal. Chem.; (Article); 2003; 75(18); 4724-4731.

 

E. B. Cummings; A. K. Singh
"Dielectrophoretic Trapping Without Embedded Electrodes"
Sandia National Laboratories, P. O. Box 969, Livermore, CA, U.S.A.

Recent Proceeding Publications

 

Fintschenko, Y., Lapizco-Encinas, B.H., Simmons, B.A., Cummings, E.B.,
Insulator-Based (Electrodeless) Dielectrophoresis for the Selective Concentration of Bacteria and Viruses
Proceedings of The Second Joint Conference on Point Detection for Chemical and Biological Defense, 2004, Williamsburg, VA, USA, Paper O2, Sample Collection & Preparation section.

 

Simmons, B.A., Lapizco-Encinas, B.H., Shediac, R., Hachman, J., Chames, J., Fiechtner, G., Cummings, E., Fintschenko, Y.,
2004, Polymeric Insulating Post Electrodeless Dielectrophoresis (Idep) for the Monitoring Of Water-Borne Pathogens.
The 27th ACS National Meeting, Anaheim, CA,
Polymer Preprints, vol. 451(1), pp. 527-528.

 

Lapizco-Encinas, B.H., Simmons, B.A., Cummings, E.B., Fintschenko, Y.,
High-Throughput Electrodeless Dielectrophoresis of Viruses in Polymeric Microdevices, Proceedings of mTAS 2003, Squaw Valley California, 2003, vol. 1, pp. 607-610.

 

Cummings, E.B., Fiechtner, G.J., Singh, A.K., Simmons, B.A., Fintschenko, Y., Lapizco-Encinas, B.H.,
Continuous Streaming Dielectrophoretic Filter/Concentrators, Proceedings of µTAS 2003, Squaw Valley California, 2003, vol. 1, pp. 44-47.

 

Fintschenko, Y., Simmons, B.A., Lapizco-Encinas, B.H., Cummings, E.B.,
Insulating post Electrodeless Dielectrophoresis for the Concentration of Bacteria,
Proceedings of µTAS 2003, Squaw Valley California, 2003, vol. 1, pp. 65-68.

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