Improvement of microchannel geometry subject to electrokinesis and dielectrophoresis using numerical simulations

Abstract

This paper addresses the effects of microchannel geometry with electrically insulating posts on a particle flow driven by electrokinesis and dielectrophoresis. An in-house numerical program is developed using a numerical model proposed in literature to predict particle flows in a microchannel with a circular post array. The numerical program is validated by comparing the results of the present study to those in the literature. Results obtained from a Monte-Carlo simulation confirm the three particle flow types driven by an external DC electric field: electrokinetic flow, streaming dielectrophoretic flow, and trapping dielectrophoretic flow. In addition, we study the effects of electrokinetic and dielectrophoretic forces on particle transports by introducing a ratio of lateral to longitudinal forces exerted on a particle. As a result, we propose an improved microchannel geometry to enhance particle transports across electrokinetic streamlines for a given power dissipation. The improved microchannel has a shorter longitudinal spacing between the circular posts than a reference microchannel. We also discuss the critical values of dimensionless variables that distinguish the three particle flow types for both improved and reference microchannels.

Tuning direct current streaming dielectrophoresis of proteins

“…We thus suspect that protein aggregation-barely resolvable in fluorescence microscopy studies-can enhance DEP forces leading to trapping at even lower electric fields. We furthermore find from calculations of the trapping criterion as developed previously [58][59][60] that the trapping condition is not satisfied in either iDEP device (see supplementary material 61 ).…”

A new approach to design an efficient micropost array for enhanced direct-current insulator-based dielectrophoretic trapping

“…Cummings and Singh already meantioned the importance of the post array distribution on the efficiency of iDEP trapping in 2003 [11], later Barbulovic-Nad et al in 2006 proposed an active method using oil droplets to adjust the insulating structure to be able to modify the trapping efficiency [19]. The idea of proving the microfluidics designers with simple equations or relationships between post array parameters started to be explored by Kwon et al in 2007 who proposed that when the longitudinal spacing between the posts was 0.6 times the post radius then the lateral-to-longitudinal force ratio was larger [20], this study ensure a maximum in area between posts, but it could be that the maximum trapping value occurred near the post walls without a guarantee that the trapping path was completely blocked. Saucedo et al in their recent study [26] already introduce the idea that to achieve filtration/trapping, trapping has to be guarantee in the line between the two posts.…”

“…Kwon et al in 2007 presented a study focused on the improvement of the circular-post geometry subject to electrokinetic (EK) and dielectrophoretic forces using a mathematical model. Their results indicated that when the longitudinal spacing between the posts was 0.6 times the post radius then the lateral-tolongitudinal force ratio was larger [20]. Nakano et al in 2011 demonstrated iDEP-based manipulation of proteins using ellipsoidal and triangular shaped posts.…”

Isolation and enrichment of low abundant particles with insulator-based dielectrophoresis

“…24,[35][36][37] For further information on the mathematical modeling of iDEP systems, we refer the reader to studies available in the literature. 24,35,38 …”