Patent ID: 8425749

Claim:
A microfabricated particle focusing device, comprising: a substrate having a front side and a back side; and an enclosed channel, on the front side of the substrate for flow of a particle-containing fluid therein, the channel comprising: an upstream acoustic portion comprising a piezoelectric transducer acoustically coupled to the back side of the substrate that couples acoustic energy straight through the substrate into the fluid for establishing an ultrasonic standing wave field in the fluid having one or more pressure nodes or anti-nodes in plane with the front side of the substrate in the fluid flow direction, and a downstream dielectrophoretic portion, separate from the upstream acoustic portion, comprising a microelectrode array disposed on the front side of the substrate for establishing one or more electric field gradient minima in the fluid in the fluid flow direction; wherein the particles in the particle-containing fluid are preconcentrated into one or more streams of particles along the pressure nodes or anti-nodes in the upstream acoustic portion when the piezoelectric transducer is energized with a radiofrequency voltage and the streams are focused into one or more columns of flowing particles near the electric field gradient minima in the downstream dielectrophoretic portion when the microelectrode array is energized with an alternating current voltage.