Exploiting Particle Mutual Interactions To Enable Challenging Dielectrophoretic Processes

Dielectrophoresis (DEP) is the motion of particles under the influence of a nonuniform electric field. In insulator-based dielectrophoresis (iDEP), the required nonuniform electric fields are generated with insulating structures embedded in a microchannel. These structures distort the electric field distribution when an electric potential is applied. This contribution presents an experimental characterization of the electrokinetic (EK) and DEP velocities of a set of target particles, under DC potentials, when additional innocuous particles are used as fillers. Streak-based particle velocimetry in a tapered channel was used to assess particle motion. Filler particles of various sizes were added at different volume fractions (ϕ) to suspending media containing the target particles/cells. The presence of the filler particles resulted in electric field distortions and dissimilar particle behaviors caused by particle–particle interactions. These particle mutual interactions were exploited to improve the enrichment of low-abundance yeast cells in an iDEP channel. It was shown that the smallest studied filler particles (500 nm) have the potential to aid the enrichment of low-abundance yeast cells when filler volume fractions ∼1 × 10^–5 v/v are used. Enrichment factors of ∼115 were achieved by applying electric potentials as low as 500 V