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Research - Per Augustsson

Acoustic focusing in microchannels

Sound carries energy that can push particles and cells. Vibrations from a piezoceramic element is bonded onto a microfluidic acoustic resonator chip. Vibrations in the MHz-range build up a standing wave across the microchannel. When the sound is turned on, particles or cells are brought to a pressure node by sound scattering forces that arise because the particles have different density and compressibility relative to the suspending liquid.


Iso-acoustic focusing cytometry                                                                                                                                                                  While flowing through a channel cells are pushed sideways by an acoustic field into media of gradually increasing density and speed of sound. Near the end, the sideways position of each cell depends on its phenotype-specific effective acoustic impedance.

Acoustic control of nanoparticles
Acoustic streaming is a steady mixing flow induced by ultrasound. By introducing liquids of slightly different density and compressibility into an ultrasound resonator we can control the streaming flow field. This enables us to focus and separate particles down to a few hundreds of nanometers in size.

CTC isolation by cell alignment and separation
Cell or particles can be precisely aligned and separated by ultrasonic fields. At the end of the separation channel 5- and 7-µm particles exit through different outlets.

Shaping flows by acoustic fields
Liquids of different density and compressibility will relocate in a predictable way when exposed to ultrasound standing wave fields.

Thermal acoustofluidics
By combining a thermal gradient and a sound field we can generate a local streaming flow.