Ultrasound Manipulation and Extrusion of Active Nanorods

Journal Article · 27 May 2023 · Small

DOI: https://doi.org/10.1002/smll.202300028 · OSTI ID:1975464

Rubio, Leonardo Dominguez  ^[1]; Collins, Matthew ^[2]; Sen, Ayusman  ^[2]; Aranson, Igor S.  ^[1]

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1. Department of Biomedical Engineering The Pennsylvania State University University Park PA 18602 USA
2. Department of Chemistry The Pennsylvania State University University Park PA 16802 USA

Abstract Synthetic self‐propelled nano and microparticles have a growing appeal for targeted drug delivery, collective functionality, and manipulation at the nanoscale. However, it is challenging to control their positions and orientations under confinement, e.g., in microchannels, nozzles, and microcapillaries. This study reports on the synergistic effect of acoustic and flow‐induced focusing in microfluidic nozzles. In a microchannel with a nozzle, the balance between the acoustophoretic forces and the fluid drag due to streaming flows generated by the acoustic field controls the microparticle's dynamics. This study manipulates the positions and orientations of dispersed particles and dense clusters inside the channel at a fixed frequency by tuning the acoustic intensity. The main findings are: first, this study successfully manipulates the positions and orientations of individual particles and dense clusters inside the channel at a fixed frequency by tuning the acoustic intensity. Second, when an external flow is applied, the acoustic field separates and selectively extrudes shape‐anisotropic passive particles and self‐propelled active nanorods. Finally, the observed phenomena are explained by multiphysics finite‐element modeling. The results shed light on the control and extrusion of active particles in confined geometries and enable applications for acoustic cargo (e.g., drug) delivery, particle injection, and additive manufacturing via printed self‐propelled active particles.

• Research Organization: Pennsylvania State Univ., University Park, PA (United States); Pennsylvania State University, University Park, PA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0020964
• OSTI ID: 1975464
• Journal Information: Small, Journal Name: Small Journal Issue: 38 Vol. 19; ISSN 1613-6810
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English