Combination Ultrasonic- Dielectrophoretic Particle Traps for Particle Trapping and Sample Purification in a Microfluidic Channel

Ultrasonic and dielectrophoretic particle manipulation have been studied for particle trajectory modification and particle trapping in microfluidic channels. We report an approach that combines dielectrophoresis (DEP) and ultrasonic fields to trap and concentrate particles and cells in an aqueous suspension. By simultaneously applying electric and ultrasonic fields to the sample, the favorable attributes of each field-based manipulation technique can be utilized. Additionally, the parameter space for sorting particles by intrinsic properties spans both acoustic (density and compressibility) and dielectric properties. Particle sorting and trapping efficiency against on-chip flow are evaluated. Two different experimental situations are presented (i) non-resonant ultrasonic excitation, and (ii) resonant ultrasonic excitation.