Acoustic trapping based on surface displacement of resonance modes

Björn Hammarström*, Nils R. Skov, Karl Olofsson, Henrik Bruus, Martin Wiklund

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

209 Downloads (Pure)


Acoustic trapping is a promising technique for aligning particles in two-dimensional arrays, as well as for dynamic manipulation of particles individually or in groups. The actuating principles used in current systems rely on either cavity modes in enclosures or complex arrangements for phase control. Therefore, available systems either require high power inputs and costly peripheral equipment or sacrifice flexibility. This work presents a different concept for acoustic trapping of particles and cells that enables dynamically defined trapping patterns inside a simple and inexpensive setup. Here, dynamic operation and dexterous trapping are realized through the use of a modified piezoelectric transducer in direct contact with the liquid sample. Physical modeling shows how the transducer induces an acoustic force potential where the conventional trapping in the axial direction is supplemented by surface displacement dependent lateral trapping. The lateral field is a horizontal array of pronounced potential minima with frequency-dependent locations. The resulting system enables dynamic arraying of levitated trapping sites at low power and can be manufactured at ultra-low cost, operated using low-cost electronics, and assembled in less than 5 min. We demonstrate dynamic patterning of particles and biological cells and exemplify potential uses of the technique for cell-based sample preparation and cell culture.

Original languageEnglish
JournalJournal of the Acoustical Society of America
Issue number3
Pages (from-to)1445-1453
Publication statusPublished - 2021

Bibliographical note

Funding Information:
The authors are grateful for financial support from the Olle Engkvist Foundation, Contract No. 2016/169, and from the Knut and Alice Wallenberg Foundation. N.R.S. was supported by a Technical University of Denmark Ph.D. Grant under the Nordic Five Tech Alliance.

Publisher Copyright:
© 2021 Acoustical Society of America.


Dive into the research topics of 'Acoustic trapping based on surface displacement of resonance modes'. Together they form a unique fingerprint.

Cite this