High-Frequency Ultrasonic Tweezers using DPLUS

Abstract

The ultrasonic manipulation technology has drawn widely attention recently due to efficient manipulation process. This report presents a high frequency operation to manipulate micro objects in the water, by ultrasonic tweezers. A low-loss and high-power ultrasonic device DPLUS (Double Parabolic reflectors wave-guided high-power ultrasonic transducer) was used as the ultrasonic tweezers. During the manipulation, a needle probe of DPLUS, which vibrates along the axis of needle, was immersed in the water and vertical to the substrate. When the distance between needle tip and substrate was a certain value, micro objects could be suspended between the substrate and vibrating needle tip, and transported by moving the vibrating needle horizontally. In our experiments, micro object samples include single copper wire with a diameter 60 μm and length of 0.5-2 mm, the cluster of yeast cell with a diameter about 15 μm (single cell has a diameter of 3-10 μm). With finite element analyses about the distribution of sound pressure, it was clarified the copper wires and cluster of yeast cells are suspended near the sound pressure nodal plane of the standing wave excited between the substrate and needle tip.