Acoustofluidic Patterning in Glass Capillaries Using Travelling Acoustic waves based on Thin Film Flexible Platform

Qiaoyun Wang, Sadaf Maramizonouz, Mercedes Stringer Martin, Jikai Zhang, Hui Ling Ong, Qiang Liu, Xin Yang, Mohammad Rahmati, Hamdi Torun, Wai Pang Ng, Qiang Wu, Richard Binns, Yongqing (Richard) Fu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Surface acoustic wave (SAW) technology has been widely used to manipulate microparticles and biological species, based on acoustic radiation force (ARF) and drag force induced by acoustic streaming, either by standing SAWs (SSAWs) or travelling SAWs (TSAWs). These acoustofluidic patterning functions can be achieved within a polymer chamber or a glass capillary with various cross-sections positioned along the wave propagating paths. In this paper, we demonstrated that microparticles can be aligned, patterned, and concentrated within both circular and rectangular glass capillaries using TSAWs based on a piezoelectric thin film acoustic wave platform. The glass capillary was placed at different angles along with the interdigital transducer
directions. We systematically investigated effects of tilting angles and wave
characteristics using numerical simulations in both circular and square shaped capillaries, and the patterning mechanisms were discussed and compared with those agitated under the SSAWs. We then experimentally verified the particle patterns within different glass capillaries using thin film ZnO SAW devices on aluminum (Al) sheets. Results show that the propagating SAWs can generate acoustic pressures and patterns in the fluid due to the diffractive effects, drag forces and ARF, as functions of the SAW device’s resonant frequency and tilting angle. We demonstrated potential applications using this multiplexing, integrated, and flexible thin film-based platform, including patterning particles (1) inside multiple and successively positioned circular tubes; (2) inside a solidified hydrogel in the glass capillary; and (3) by wrapping a flexible ZnO/Al SAW device around the glass capillary.
Original languageEnglish
Article number107149
Number of pages12
Early online date3 Sept 2023
Publication statusPublished - 1 Jan 2024

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