Acoustic microbubble propulsion, train-like assembly and cargo transport

• Published in: Nature communications Vol. 14; no. 1; p. 4705
• Main Authors: Janiak, Jakub, Li, Yuyang, Ferry, Yann, Doinikov, Alexander A., Ahmed, Daniel
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.08.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/988; 639/766/25/3927; Acoustics; Automation; Biomedical materials; Cargo transportation; Humanities and Social Sciences; Incident waves; Manufacturing engineering; Microfluidics; Microparticles; multidisciplinary; Robotics; Science; Science (multidisciplinary); Self-assembly; Sound fields; Viscous fluids
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-40387-7

Achieving controlled mobility of microparticles in viscous fluids can become pivotal in biologics, biotechniques, and biomedical applications. The self-assembly, trapping, and transport of microparticles are being explored in active matter, micro and nanorobotics, and microfluidics; however, little work has been done in acoustics, particularly in active matter and robotics. This study reports the discovery and characterization of microbubble behaviors in a viscous gel that is confined to a slight opening between glass boundaries in an acoustic field. Where incident waves encounter a narrow slit, acoustic pressure is amplified, causing the microbubbles to nucleate and cavitate within it. Intermittent activation transforms microbubbles from spherical to ellipsoidal, allowing them to be trapped within the interstice. Continuous activation propels ellipsoidal microbubbles through shape and volume modes that is developed at their surfaces. Ensembles of microbubbles self-assemble into a train-like arrangement, which in turn capture, transport, and release microparticles. Experiments show how confined microbubbles in a viscous gel can be controllably moved by means of an acoustic field. Ensembles of such microbubbles can be made to self-assemble into a train-like arrangement, which can trap, transport and release microparticles.