Particle Accumulation by AC Electroosmosis in Microfluidic Device with Co-Planar Electrodes

Abstract

This paper reports a particle accumulation driven by alternating-current electroosmosis (ACEO) in a microfluidic device with co-planar electrode. Accumulation processes of particles in single-and double-gap electrode device were investigated. The flow field of ACEO and flow-induced particle accumulation process were measured by the micron-resolution particle tracking velocimetry and fluorescent intensity analysis, respectively. Particles in a solution are concentrated gradually from an electrode edge close to gap at the entrance and converged into a certain location downstream. Contribution of ACEO to particle transportation and eventual accumulation was discussed, and dependences of experimental parameters on the accumulating position were evaluated as well. The particle concentration behavior can be classified into two types; one has similar accumulating characteristics in both gap patterns, the other is the case in which particles are concentrated at the center span of the channel. Consequently, it is indicated from the results in this study that an estimation of the particle concentration is possible in a device with more complicated electrode geometry based on that in the single-gap device. The particle focusing method by ACEO can contribute to an improvement of detection sensitivity in the microfluidic system.

Tuning AC Electrokinetic Flow to Enhance Nanoparticle Accumulation in Low‐Conductivity Solutions

“…The accumulation of particles in these high CF spots is caused by the ACEO flow, which entrains particles from the bulk toward the electrode surface. [ 27 ] The CF values in these regions reached up to five times the initial concentration. The intensity distribution after applying voltage was normalized by using the image obtained without voltage.…”

“…Eventually, the particles experienced a combination of DEP and ACEO forces, which caused them to accumulate along the electrode in two different area, which were far from the edge. [ 27 ] In contrast, at high frequencies, the advective forces pushed the particles toward the gap center, where they accumulated in a single area. This accumulation mode inside the electrode gap has not been reported previously.…”

“…The AC method offers various advantages over the DC method, including a lower temperature rise due to Joule heating and less electrolysis of the solution. [7] AC electrokinetics is an efficient approach for particle manipulation, [25] concentration [26] and focusing, [27][28][29] demonstrating its potential for use in various applications. In AC electrokinetic techniques, particles are driven through a microfluidic device, and forces, such as dielectrophoretic (DEP), AC electroosmosis (ACEO), or AC electrothermal flow (ACET), are applied to the particles or solution to manipulate the particles.…”

Bionanotechnology and bioMEMS (BNM): state-of-the-art applications, opportunities, and challenges

“…This effect works both under static flow conditions and in an imposed flow. 176,177 Importantly, the effect is sizeindependent, working as well (and at the same speed) with macromolecules and viruses as it does with bacteria and cells of all sizes. 178 Furthermore, it serves multiple functions.…”

Review: Electric field driven pumping in microfluidic device

“…For instance, ACEO pumping is combined with dielectrophoresis for the collection of cells [122] and particles [123], separation of colloids [124], rotation [125] and manipulation [126] of particles in a microfluidic chip. Similarly, by combining with other microfluidic-based actuation technique, ACEO pumping is used for separation and concentration [127-130] and detection [131-134].…”