Particle Manipulation by a Novel Lamb Wave Resonator Array with Grating Reflectors

Acoustic methods based on lamb waves are expected to be a promising tool for the manipulation of bio-particles, by virtue of the miniaturization and low-power consumption of lamb wave resonators (LWRs). We utilize the streaming effects induced by acoustic waves propagating in the fluid to concentrate particles in a circular trajectory. However, multiple vortices which gather particles can be generated by a normal L WR, reducing the capture efficiency. In this device, the L WR was optimized into a novel structure with reflection gratings on one side, preventing the propagation of acoustic waves to the liquid from both sides simultaneously. By means of the ring array comprising eight L WRs with novel structures, only one vortex with the linear speed exceeding 80mm/s under the applied power of 30mW was generated in the center of the array. The acoustic pressure and flow field of the novel array were simulated by an FEA model. The proposed novel L WR structure provides a viable approach for the flexible generation of streaming patterns, which is of great significance for building more complex manipulation platforms for particles and cells in a bio-compatible and contactless manner.