On-demand particle enrichment in a microfluidic channel by a locally controlled floating electrode

Yalcin, Sinan E. ; Sharma, Ashutosh ; Qian, Shizhi ; Joo, Sang W. ; Baysal, Oktay (2011) On-demand particle enrichment in a microfluidic channel by a locally controlled floating electrode Sensors and Actuators B: Chemical, 153 (1). pp. 277-283. ISSN 0925-4005

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/j.snb.2010.10.025

Abstract

A flexible strategy for the on-demand control of the particle enrichment and positioning in a microfluidic channel is proposed and demonstrated by the use of a locally controlled floating metal electrode attached to the channel bottom wall. The channel is subjected to an axially acting global DC electric field, but the degree of charge polarization of the floating electrode is governed largely by a local control of the voltage applied to two micron-sized control electrodes (CEs) on either side of the floating electrode (FE). This strategy allows an independent tuning of the electrokinetic phenomena engendered by the floating electrode regardless of the global electric field across the channel, thus making the method for particle manipulation far more versatile and flexible. In contrast to a dielectric microchannel wall possessing a nearly uniform surface charge (or zeta potential), the patterned metal strip (floating electrode) is polarized under electric field resulting in a non-uniform distribution of the induced surface charge with a zero net surface charge, and accordingly induced-charge electro-osmotic (ICEO) flow. The ICEO flow can be regulated by the control electric field through tuning the magnitude and polarity of the voltage applied to the CEs, which in turn affects both the hydrodynamic field as well as the particle motion. By controlling the control electric field, on-demand control of the particle enrichment and its position inside a microfluidic channel has been experimentally demonstrated.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Particle Enrichment; Floating Electrode; Polarization; Induced-Charge Electro-Osmosis (ICEO)
ID Code:96564
Deposited On:26 Dec 2012 10:42
Last Modified:26 Dec 2012 10:42

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