Observations and analysis of electrokinetically driven particle trapping in planar microelectrode arrays

Abstract

In situ observations of submicron fluorescent tracers suspended in high ionic strength media sealed in a confined geometry are combined with 3-D simulations in order to provide a better understanding of the synergism between dielectrophoresis and electrothermal flows that cause rapid particle transport and trapping on the surface of planar quadrupolar microelectrodes. The influence of electrode design on the microfluidic patterns and observed particle collection is examined by employing two different types of microelectrodes in the experiments. The potential use of quadrupolar microelectrodes as means for achieving accelerated sampling and signal amplification in future surface based biosensor devices is illustrated with an experiment involving stable capture of antigen-coated polystyrene particles on the surface of an antibody-functionalized microelectrode array.Des observations in situ de traceurs fluorescents submicroniques en suspension dans des milieuxà force ioniqueélevée enfermés dans une configuration confinée sont combinéesà des simulations en 3-D dans le but de mieux comprendre la synergie entre lesécoulements de type diélectrophorèse etélectrothermique qui entraînent un transport rapide des particules et le piégeageà la surface des microélectrodes quadrupolaires planaires. On examine l'influence de la conception desélectrodes sur les schémas microfluidiques et la collecte des particules observées en employant deux types différents de microélectrodes dans les expériences. L'utilisation potentielle des microélectrodes quadrupolaires comme moyen de réaliser unéchantillonnage accéléré et l'amplification des signaux dans les biosenseurs futurs basés sur des surfaces, est illustréeà l'aide d'une expérience faisant appelà la saisie stable de particules de polystyrène enduites d'antigèneà la surface d'une rangée de microélectrodes fonctionnalisées par un anticorps.

Enhancing the Performance of Surface-based Biosensors by AC Electrokinetic Effects - a Review

“…The circulation zones appear to be similar to a microfluidic system subjected to AC electroosmotic flow. (Tomkins et al, 2008).…”

Microelectrode Design for Particle Trapping on Bioanalysis Platform

“…In recent years, dielectrophoresis (DEP) has contributed to the recent advancements of particle trapping technologies. The common microelectrode geometries for DEP are planar electrode arrays [1], quadruple [2], interdigitated (IDE) [3] or planar ring arrays [4][5][6]. Each design is customized to accommodate electric field non-uniformity, size of particles and type of physical manipulations required.…”

“…These models work in 2D geometric domains using time-dependent mode utilizing electrostatics model for faster and more accurate results [11]. Results show that the designed V-shaped microelectrode tips provide the largest electric field gradient and consequently the highest DEP force to trap particles [1]. This is crucial especially in applications where continuous fluid flows that regulate the suspension media.…”

Trapping Single Cells: Comparison between Sandwiched Insulation with Back Contact (SIBC) and Planar Biochip

“…However, particle movements away from the microelectrode i.e. either in vertical or horizontal directions, have significant impact over the DEP holding force exerted on it [6].…”