On-chip acoustic manipulation of single or arrayed microparticles via standing Scholte waves

Abstract

Contactless acoustic manipulation of suspended particles via radiation force control is a promising approach for microfluidic applications. Here, we introduce a method that uses standing Scholte waves to precisely transport and position microparticles within a disposable, low-cost microfluidic chip. The device, fabricated without cleanroom facilities, integrates a single piezoelectric transducer with a glass-based microchannel to generate tunable Scholte wave patterns through dynamic frequency modulation. Stepwise frequency adjustments enable controllable particle transport with micrometer-scale accuracy, allowing reversible trapping at any transverse location or propulsion to the channel boundary. Particle speeds are voltage-tunable from 0 to ∼60 μm/s (0–24 Vpp). Measured Scholte wave velocities (1200–1500 m/s) agree with dispersion modeling, validating the design. This approach establishes Scholte wave-based acoustomicrofluidics as an energy-efficient platform for active particle manipulation, overcoming limitations of conventional surface and bulk acoustic wave systems.