A novel density-based dielectrophoretic particle focusing technique for digital microfluidics

In the present study a particle focusing technique has been developed for digital microfluidics (DMF) based on cumulative effects of negative dielectrophoretic (nDEP) and gravitational forces. The mechanism of the proposed technique has been studied for different particles, and different magnitudes and frequencies of the applied voltage. Particle focusing using the proposed technique was found to be more efficient for particles with a large diameter and high density. To show a potential application of this method, it was applied to collect particles on one side of a large droplet which was split on a DMF platform into two daughter droplets with very low and very high particle concentrations.