Wireless Frequency-Multiplexed Acoustic Array-based Acoustofluidics

Acoustofluidics has shown great potential in enabling on-chip technologies for driving liquid flows and manipulating particles and cells for engineering, chemical, and biomedical applications. To introduce on-demand liquid sample processing and micro/nano-object manipulation functions to wearable and embeddable electronics, wireless acoustofluidic chips are highly desired. This paper presents wireless acoustofluidic chips to generate acoustic waves carrying sufficient energy and achieve key acoustofluidic functions, including arranging particles and cells, generating fluid streaming, and enriching in-droplet particles. To enable these functions, our wireless acoustofluidic chips leverage mechanisms, including inductive coupling-based wireless power transfer (WPT), frequency multiplexing-based control of multiple acoustic waves, and the resultant acoustic radiation and drag forces. For validation, the wirelessly generated acoustic waves are measured using laser vibrometry when different materials (e.g., bone, tissue, and hand) are inserted between the WPT transmitter and receiver. Moreover, our wireless acoustofluidic chips successfully arrange nanoparticles into different patterns, align cells into parallel pearl chains, generate streaming, and enrich in-droplet microparticles. We anticipate this research to facilitate the development of embeddable wireless on-chip flow generators, wearable sensors with liquid sample processing functions, and implantable devices with flow generation and acoustic stimulation abilities for engineering, veterinary, and biomedical applications.