Acoustic manipulation of microparticles using a two-dimensional phononic crystal plate

Abstract

Acoustic waves can manipulate particles without contact or damage, and has received increasing attention due to their potential applications in various fields, such as cell sorting, organoid construction, and material assembly. In general, high-throughput manipulation of microparticles relies on a large number of active transducers and phase-shifting circuits to create standing wave patterns, thus significantly inducing system complexity. Recently, we realized the parallel manipulation of microparticles by using an acoustic field modulated by a one-dimensional phononic crystal plate. The concept is based on the fact that phononic crystal plate can resonantly excite the zero-order asymmetric (<i>A</i><sub>0</sub>) Lamb wave, inducing highly localized periodic radiation force on the particles. In this paper, we further show that by using a two-dimensional phononic crystal plate (TDPCP), parallel manipulation of massive particles can be achieved only with a single transducer. The <i>A</i><sub>0</sub> Lamb wave can be excited by a TDPCP, forming a two-dimensional periodic localized field, and then particles can suffer negative vertical force and stable zero horizontal force, inducing two-dimensional periodic trapping on the surface of the plate. Combining a PZT source with a TDPCP consisting of a brass plate patterned with periodical brass stubs, we observe the capture and arrangement of glass microspheres, achieving two-dimensional arrangement manipulation of particles on the TDPCP. This system represents a significant advancement in developing high-throughput, rapid, and flexible devices for particles and cell manipulation.