Ultrasonic particle trapping in microfluidic devices using soft lithography

Abstract

We report on the feasible fabrication of microfluidic devices for noncontact particle trapping. A half-wavelength resonator was constructed using standard soft lithography to generate ultrasonic standing waves through a miniature piezoelectric transducer. Microparticles (400 nm to 10 µm in diameter) flowing through polydimethylsiloxane microchannels were efficiently trapped to levitate in the middle depth of a resonance cavity. Such a device could potentially offer a flexible platform for particle-based assays for a large variety of applications.