Manipulating microscopic objects with sound

Researchers from the SNI network recently published their findings on using acoustic tweezers — devices that manipulate tiny objects using sound waves without solid contact— in a more efficient and sustainable manner. Rather than using a single chip, the researchers used a combination of a reusable sonic chip and a disposable microfluidic chip. This allowed them to conduct the experiments more cost-effectively and with minimized cross-contamination between experiments.

By carefully tuning the sound frequencies, the team from the Paul Scherrer Institute (PSI) and the Biozentrum at the University of Basel generated strong pressure waves (up to 2.1 MPa), with which living cells could be successfully captured and compressed. "This worked with fast swimmers such as the single-celled organism Tetrahymena as well as with human cells. “We also investigated how human cells deform under acoustic forces – which could help us to better understand cell mechanics,” explains the first author and a former SNI PhD student Dr. Shichao Jia. 

This new platform has great potential for investigating soft materials and biological samples – using the power of sound.

The work was primarily conducted as a doctoral thesis at the SNI PhD School and was supervised by Dr. Soichiro Tsujino (PSI) and Argovia- Professor Roderick Lim of the Biozentrum at the University of Basel. The researchers recently published their findings in the scientific journal IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

Original publication:
S. Jia, H. Guo, R. Y. H. Lim and S. Tsujino
Surface-Acoustic-Wave-Driven Acoustic Tweezing in a Silicon Microfluidic Chip
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 72, no. 8, pp. 1005-1014, August. 2025
doi: 10.1109/TUFFC.2025.3581642

Further information:
S. Tsujino, Laboratory for Multiscale Bioimaging, Ultrasound Mechanobiology
Research group Prof. R. Lim