Acoustic Particle Manipulation Along Three Orthogonal Directions in Laser Engraved Microfluidic Channels

Acoustofluidic particle manipulation in three orthogonal directions was performed in simple and low-budget microfluidic chips that were laser-engraved and laser-cut out of polymethylmethacrylate sheets. Besides the focusing and separation of particles orthogonal to the channel axis, which can be used in so-called flow through separators, we were also able to accumulate the particles at acoustic vibration nodes along the channel axis and to lift them up in vertical direction in the same experimental configuration. An application of the latter effect is demonstrated, by considering particles that are slowly dragged along the bottom of a microfluidic channel by the streaming fluid and which move significantly faster as they are lifted upwards.