Acoustic 3D trapping of microparticles in flowing liquid using circular cavity

Abstract

We report a simple and compact microchip capable of stable 3D trapping of single and multiple microparticles in the flowing liquid. The chip is constructed by attaching a piezoelectric plate transducer to a silicon-glass bonding plate with circular cavity. The cavity works as a resonant unit, excited at frequency of both half wave resonance in main plane and inverted quarter wave resonance in depth direction. The chip can provide nN level trapping force and ms level trapping time for micron sized particles moving at velocity of mm/s level. The time consumption of 3 µm polystyrene particles trapping under 15Vpp driving amplitude is 103 ms. Red blood cells cluster can be trapped at flow rate of 32 μL/min which corresponds to flow velocity of 60 mm/s. This circular cavity resonance based acoustic trap is simple, low cost, biocompatible, and with its high throughput trapping ability, which may be of interest for applications such as Reman analysis and seed particle-enabled nanoparticles enrichment.