Ultrasonic separation in microfluidic capillaries

We present a new actuator based on glass capillary bonded to laser-cut PZT plate, for ultrasonic control of microparticles inside microfluidic channels. The actuator generates high velocity bending mode at low CMOS compatible 5-10 Vpp drive. The high velocity enables focusing of samples at the nodes and the antinodes of the bending waves in the capillary. Separation of 3 and 10 microns polystyrene microbeads in space by 800 /spl mu/m is achieved. E. Coli cells and blood cells can also be separated with particles with lower density than water being placed at the transverse velocity nodes and heavier particles at the antinodes.