Transducer arrays for ultrasonic particle manipulation

Ultrasonic particle manipulation tools have many promising applications in life sciences research, expanding on the capabilities of current manipulation technologies. In this paper the feasibility of ultrasonic manipulation of particles and cells along a microfluidic channel with an array is investigated. An array integrated into a multilayer resonator structure drives particles towards the pressure nodal plane along the axis of the channel, then towards the acoustic velocity maximum centered above the driven elements. Switching the active elements along the array moves trapped particles along the microfluidic channel. A 1-D array coupled to a rectangular capillary has been simulated and fabricated for experimental testing. The device has a 300 μm thick channel for a half wavelength resonance near 2.5 MHz, and 500 μm element pitch. Simulation and experiment confirm the expected trapping of particles at the centre of the channel and above the set of driven elements. Experiments demonstrated the feasibility of controlling the position of particles along the length of the channel by switching the driven array elements.